far - Page 450 - Developer IT

Setting up a server that routes local traffic through vpn, while still being able to access internet directly

- by Kazuo

The goal is to setup a local server that routes local traffic through an uncontrolled remote vpn service while still being able to access the internet directly (not tunneled via vpn) and provide services through that direct connection. It is supposed to look like this: http://i.stack.imgur.com/74dGC.png Note: There is another router with modem between the local server and the internet. What is the easiest (best?) way to get this network setup working? I'm planning to setup the connection between the local router and the local server with simple ip forwarding. The problem now is that all the server's traffic is routed through the vpn tunnel as soon as I connect the server's openvpn client to the remote service so there is no direct internet connection available. My first idea was to setup a virtual machine (lxc container or something) and run the vpn client and local networking stuff in the vm. So that the vm receives all the incoming traffic from the local router and tunnels it through the vpn. This, as far as I understand, should not affect the physical server's network connection and should allow it to provide services to the internet. Before I start trying to set this up (I don't have much experience in networking), is there any easier or better way to do this? I would be thankful for every suggestion. Edit: Let's say the interface connected to the internet is eth0 and the interface connected to the local router is eth1. Another idea would be to create a virtual interface eth0:0 and specifiy it as openvpn's local endpoint and then force any traffic coming from eth1 through eth0:0. I'm not sure how I would force the traffic through eth0:0, though (possibly by adding routes).

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How to turn a DSL wireless modem to a wifi hub

- by my_question

I used to use DSL for my home internet and used Qwest Q1000 wireless modem. Now I switched to cable and use wireless router to cover the home. One problem is I just bought a desktop and I like to put it in a place far away from the router. The desktop only has cable interface, it does not receive wifi. The obvious solution is I go buy that little USB dongle which can receive wifi and plug it to the desktop. But before doig that, I am wondering if somehow I can re-use the Q1000 modem. The modem has 4 LAN ports and it has wifi antenna. I tried connecting the desktop to Q1000's LAN port, the system shows wire connection is in place, but I cannot access internet. It seems to me Q1000's wifi function is to broadcast the wifi signal out instead of receiving signal. I went to the Q1000 configuration page by going to web page of "192.168.0.1", it is not clear how to set it up. I also wonder one thing, my home wifi is encrypted, so if I want to let Q1000 to join the wifi, I need to somehow type in the password, I am not sure how to do that either. Anyway, maybe this thing cannot be used in this fashion. If you have any suggestion, please shed some light. Thanks.

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cannot connect to my nginx server from remote machine

- by margincall

I thought that it's iptables problem.. but it seems not. I really have no idea about this situation. I'm getting a server hosting(CentOS). I installed Nginx + Django and nginx uses 8080 port. A domain is connected to the server. When I executed "wget [domain]:8080/[app name]/" in the server, it worked. Of course, "wget 127.0.0.1:8080/[app name]/" has no problem. (wget [server ip]:8080/[app name]/, either) However, from other computers, connecting was failed. (message says, no route) I checked my firewall setting. I excuted these commands. iptables -I INPUT -p tcp --dport 8080 -j ACCEPT iptables -I OUTPUT -p tcp --sport 8080 -j ACCEPT iptables -A RH-Firewall-1-INPUT -m state --state NEW -m tcp -p tcp --dport 8080 -j ACCEPT /etc/init.d/iptables restart I don't really understand all options of commands and I think there were useless commands, but I just tried all googled iptables settings. But still I cannot connect to my server. What should I check, first? I don't know this is important, but add to this post. On 80 port, an apache server is running. It works fine, I can connect to apache from other computers. There is DB connecting issue, (PHP to MySQL) but I think that it is just PHP coding bug. please excuse my low-level English. I'm not native English speaker.. but I tried to explane well as far as possible. Thank you for reading this question.

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Adding a 2008 server to a 2003 Domain with DNS devolution?

- by mvdwege

I'm running into a problem adding a 2008 server to our existing 2003 domain, and as I am not a Windows admin, I'm not getting the problem here. Some reading around on Technet seems to indicate that DNS devolution is the issue. Here's the setup: DNS for the entire company is hosted on a Unix server running Bind, including the service records for the Windows domain. Our toplevel is company.local, and functional domains are in subdomains, such as mgt.company.local (our management servers). Our Windows servers live mostly in office.company.local, but some of them live in .mgt.company.local and .customers.company.local. The 2003 servers all succesfully authenticate against company.local as the Windows domain. Their position in the infrastructure is set by setting the primary DNS suffix under the network settings and the computer name dialog. Trying to do the same with a brand new 2008 install throws an error though: "Changing the Primary Domain DNS name of this computer to office.company.local failed [...] The specified server cannot perform the requested operation" I tried googling, but the closest I came was the Technet article on DNS Devolution, and I can't make heads nor tails on how to apply that to my case. Addendum 2012-10-23: The problem is not joining the domain, that works, the problem is that it joins with the wrong name, as .company.local, instead of .office.company.local. So far everything works, but I'm rather afraid to run production like this, because sooner or later something is going to complain about the AD name not matching DNS.

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Two video card on one Mobo

- by InfinityKing

I recently purchased a new HP Pavilion p6-2265eo. It was then that I realised that it has only one DVI and one HDMI output.. I will connect my TV with the HDMI. so I am letft with only one DVI output. I need to have two monitors. Please help. Should I purchase a new video card and install it? My knowledge is limited. The specifications of my comp says that there is 1 x PCI-E x16, 3 x PCI-E x1. 1) I suppose that the video card already present in my purchase is connected on the PCI-E x16. Am I right? I dont want to open my desktop right now and check it for myself as it can void the warrenty. so I need an experienced person to tell me that. 2) I have an old nvidia geforce 7200 gt. Is it possible for me to connect it to my left over PCI-E x1? I searched for PCI-E x1 on the net and as far as I can understand the slot is too small for my old nvidia geforce 7200 gt graphic card. 3) what are the options? Please help this dummo :) Thankign you in advance,

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Fedora 13 becomes unresponsive when too many applications running.

- by user61766

I am using Fedora 13 64bit on Dell Vostro full 4GB RAM system with default Gnome GUI. This is very annoying problem that I don't how to fix except by rebooting the whole PC. When I have too many applications running ( like browser windows), the system start acting sluggish. The fist symptoms appear in Eclipse IDE which becomes so terrible it just becomes frozen for sometime one whole minute after I try to edit something in the editor. Then Firefox seems like it has crashed. Google Chrome becomes very unresponsive as well. All GUI applications including File manager becomes unresponsive. When I check System Monitor, the CPU is still around 20% and memory is at 80% but the system seems getting fried up. This progressively becomes worse until I soft reboot it or if I dont do it evetually the whole system is fried, no response to any keyboard key or mouse and I have to hit the hardware turn off button. I regularly yum update the system but this makes no difference. Please don't tell not to run too many applications because I need those for my work. I thought Linux is well designed Operating System but I am very disappointed so far. Can some one here help ?

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Linux Server partitioning

- by user1717735

There's a lot of infos about this out there, but there's also a lot of contradictory infos… That's why i need some advices about it. So far, on the servers i had home for test (or even "home production") purposes i didn't really care about partitioning and i configured all in / + a swap partition, over RAID 0. Nevertheless, this pattern can't apply to production servers. I have found a good starting point here, but also it depends on what the servers will be used for… So basically, i have a server on which there will be apache, php, mysql. It will have to handle file uploads (up to 2GB) and has 2*2TB hard drive. I plan to set : / 100GB, /var 1000GB (apache files and mysql files will be here), /tmp 800GB (handles the php tmp file) /home 96GB swap 4GB All of this if of course over RAID 1. But actually, it's not a big deal if I lose data being uploaded, so would it be interesting mounting /tmp over raid 0 while maintaining the rest over raid 1? Sounds complicated…

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Mysql: Working With 192 Trillion Records... (Yes, 192 Trillion)

- by Sarah

Here's the question... Considering 192 trillion records, what should my considerations be? My main concern is speed. Here's the table... CREATE TABLE `ref` ( `id` INTEGER(13) AUTO_INCREMENT DEFAULT NOT NULL, `rel_id` INTEGER(13) NOT NULL, `p1` INTEGER(13) NOT NULL, `p2` INTEGER(13) DEFAULT NULL, `p3` INTEGER(13) DEFAULT NULL, `s` INTEGER(13) NOT NULL, `p4` INTEGER(13) DEFAULT NULL, `p5` INTEGER(13) DEFAULT NULL, `p6` INTEGER(13) DEFAULT NULL, PRIMARY KEY (`id`), KEY (`s`), KEY (`rel_id`), KEY (`p3`), KEY (`p4`) ); Here's the queries... SELECT id, s FROM ref WHERE red_id="$rel_id" AND p3="$p3" AND p4="$p4" SELECT rel_id, p1, p2, p3, p4, p5, p6 FROM ref WHERE id="$id" INSERT INTO rel (rel_id, p1, p2, p3, s, p4, p5, p6) VALUES ("$rel_id", "$p1", "$p2", "$p3", "$s", "$p4", "$p5", "$p6") Here's some notes... The SELECT's will be done much more frequently than the INSERT. However, occasionally I want to add a few hundred records at a time. Load-wise, there will be nothing for hours then maybe a few thousand queries all at once. Don't think I can normalize any more (need the p values in a combination) The database as a whole is very relational. This will be the largest table by far (next largest is about 900k) UPDATE (08/11/2010) Interestingly, I've been given a second option... Instead of 192 trillion I could store 2.6*10^16 (15 zeros, meaning 26 Quadrillion)... But in this second option I would only need to store one bigint(18) as the index in a table. That's it - just the one column. So I would just be checking for the existence of a value. Occasionally adding records, never deleting them. So that makes me think there must be a better solution then mysql for simply storing numbers... Given this second option, should I take it or stick with the first... [edit] Just got news of some testing that's been done - 100 million rows with this setup returns the query in 0.0004 seconds [/edit]

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SSH access to VM on windows 8 hyper-v

- by samw

I'm currently attending University and prefer a Linux environment to do much of my work, but all I have is a ThinkPad running Windows 8 Pro. Cygwin is nice, but it leaves me missing things like apt-get. My latest solution is to run an Ubuntu 12.04 VM with Windows 8's Client Hyper-V and use Cygwin for SSH access. I've looked everywhere online trying to set this up, but I haven't found much help. I've done this before using VirtualBox, so I figured this would be possible as well. Could anyone provide advice for setting up this environment? I'm completely uninitiated to Linux networking, virtual networking, and... pretty much all networking configuration, so this has been quite a challenge for me. What I've done so far: Created an external virtual switch to my wireless NIC. With this, I could successfully SSH to the VM with the leased IP address. But without a static IP, I would soon get disconnected. Created an internal virtual switch and attempt to "share" my main internet connection. (I was following the description on this page) Thank you all in advance!

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Reporting SQL Vulnerability [migrated]

- by Ciaran87Bel

My first post here so i'll hopefully keep it simple. I have just finished building a CMS targeted at a certain industry and built a test site to see how everything works. Anyway I wrote a program to check for sql injection vulnerabilities and the program followed a blog link to an external website. The program discovered that the external site had a massive vulnerability that left it open to practically anyone who could then access every bit of data on their MYSQL Server and run queries etc. The thing is this external site is the brand leader in their industry and do millions upon millions of sales per annum. I have tried contacting them to let them know and even went as far as contacting the company that built their platform but I was pretty much brushed off and haven't heard back from them. Their database would contain the details of hundreds of thousands of customers and all their data. I could easily make myself site admin etc in a few seconds but they won't listen to me even though I have offered to share the vulnerability with them and help in anyway I can. Is there anything else I can do because it is one of the biggest security risks I have ever personally come across. Is there any other steps I should take to report this? Thanks

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Silverlight Recruiting Application Part 6 - Adding an Interview Scheduling Module/View

Between the last post and this one I went ahead and carried the ideas for the Jobs module and view into the Applicants module and view- they're both doing more or less the same thing, except with different objects being at their core. Made for an easy cut-and-paste operation with a few items being switched from one to another. Now that we have the ability to add postings and applicants, wouldn't it be nice if we could schedule an interview? Of course it would! Scheduling Module I think you get the drift from previous posts that these project structures start looking somewhat similar. The interview scheduling module is no different than the rest- it gets a SchedulingModule.cs file at the root that inherits from IModule, and there is a single SchedulerView.xsml and SchedulerViewModel.cs setup for our V+VM. We have one unique concern as we enter into this- RadScheduler deals with AppointmentsSource, not ItemsSource, so there are some special considerations to take into account when planning this module. First, I need something which inherits from AppointmentBase. This is the core of the RadScheduler appointment, and if you are planning to do any form of custom appointment, you'll want it to inherit from this. Then you can add-on functionality as needed. Here is my addition to the mix, the InterviewAppointment: 01.public class InterviewAppointment : AppointmentBase 02.{ 03. private int _applicantID; 04. public int ApplicantID 05. { 06. get { return this._applicantID; } 07. set 08. { 09. if (_applicantID != value) 10. { 11. _applicantID = value; 12. OnPropertyChanged("ApplicantID"); 13. } 14. } 15. } 16. 17. private int _postingID; 18. public int PostingID 19. { 20. get { return _postingID; } 21. set 22. { 23. if (_postingID != value) 24. { 25. _postingID = value; 26. OnPropertyChanged("PostingID"); 27. } 28. } 29. } 30. 31. private string _body; 32. public string Body 33. { 34. get { return _body; } 35. set 36. { 37. if (_body != value) 38. { 39. _body = value; 40. OnPropertyChanged("Body"); 41. } 42. } 43. } 44. 45. private int _interviewID; 46. public int InterviewID 47. { 48. get { return _interviewID; } 49. set 50. { 51. if (_interviewID != value) 52. { 53. _interviewID = value; 54. OnPropertyChanged("InterviewID"); 55. } 56. } 57. } 58. 59. public override IAppointment Copy() 60. { 61. IAppointment appointment = new InterviewAppointment(); 62. appointment.CopyFrom(this); 63. return appointment; 64. } 65. 66. public override void CopyFrom(IAppointment other) 67. { 68. base.CopyFrom(other); 69. var appointment = other as InterviewAppointment; 70. if (appointment != null) 71. { 72. ApplicantID = appointment.ApplicantID; 73. PostingID = appointment.PostingID; 74. Body = appointment.Body; 75. InterviewID = appointment.InterviewID; 76. } 77. } 78.} Nothing too exciting going on here, we just make sure that our custom fields are persisted (specifically set in CopyFrom at the bottom) and notifications are fired- otherwise this ends up exactly like the standard appointment as far as interactions, etc. But if we've got custom appointment items... that also means we need to customize what our appointment dialog window will look like. Customizing the Edit Appointment Dialog This initially sounds a lot more intimidating than it really is. The first step here depends on what you're dealing with for theming, but for ease of everything I went ahead and extracted my templates in Blend for RadScheduler so I could modify it as I pleased. For the faint of heart, the RadScheduler template is a few thousand lines of goodness since there are some very complex things going on in that control. I've gone ahead and trimmed down the template parts I don't need as much as possible, so what is left is all that is relevant to the Edit Appointment Dialog. Here's the resulting Xaml, with line numbers, so I can explain further: 001.<UserControl.Resources> 002.  003. <helpers:DataContextProxy x:Key="DataContextProxy" /> 004. 005. <telerik:Windows7Theme x:Key="Theme" /> 006. <SolidColorBrush x:Key="DialogWindowBackground" 007. Color="White" /> 008. <SolidColorBrush x:Key="CategorySelectorBorderBrush" 009. Color="#FFB1B1B1" /> 010. <LinearGradientBrush x:Key="RadToolBar_InnerBackground" 011. EndPoint="0.5,1" 012. StartPoint="0.5,0"> 013. <GradientStop Color="#FFFDFEFF" 014. Offset="0" /> 015. <GradientStop Color="#FFDDE9F7" 016. Offset="1" /> 017. <GradientStop Color="#FFE6F0FA" 018. Offset="0.5" /> 019. <GradientStop Color="#FFDCE6F4" 020. Offset="0.5" /> 021. </LinearGradientBrush> 022. <Style x:Key="FormElementTextBlockStyle" 023. TargetType="TextBlock"> 024. <Setter Property="HorizontalAlignment" 025. Value="Right" /> 026. <Setter Property="VerticalAlignment" 027. Value="Top" /> 028. <Setter Property="Margin" 029. Value="15, 15, 0, 2" /> 030. </Style> 031. <Style x:Key="FormElementStyle" 032. TargetType="FrameworkElement"> 033. <Setter Property="Margin" 034. Value="10, 10, 0, 2" /> 035. </Style> 036. <SolidColorBrush x:Key="GenericShallowBorderBrush" 037. Color="#FF979994" /> 038. <telerik:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" /> 039. <telerikScheduler:ImportanceToBooleanConverter x:Key="ImportanceToBooleanConverter" /> 040. <telerikScheduler:NullToVisibilityConverter x:Key="NullToVisibilityConverter" /> 041. <telerikScheduler:InvertedNullToVisibilityConverter x:Key="InvertedNullToVisibilityConverter" /> 042. <scheduler:ResourcesSeparatorConverter x:Key="ResourcesSeparatorConverter" /> 043. <DataTemplate x:Key="IconDataEditTemplate"> 044. <Image Source="/Telerik.Windows.Controls.Scheduler;component/Themes/Office/Images/cal.png" 045. Margin="3,3,0,0" 046. Width="16" 047. Height="16" /> 048. </DataTemplate> 049. <DataTemplate x:Key="SingleSelectionTemplate"> 050. <Grid VerticalAlignment="Stretch" 051. HorizontalAlignment="Stretch"> 052. <Grid.RowDefinitions> 053. <RowDefinition Height="Auto" /> 054. </Grid.RowDefinitions> 055. <Grid.ColumnDefinitions> 056. <ColumnDefinition Width="Auto" 057. MinWidth="84" /> 058. <ColumnDefinition Width="Auto" 059. MinWidth="200" /> 060. </Grid.ColumnDefinitions> 061. <TextBlock x:Name="SelectionNameLabel" 062. Margin="0,13,4,2" 063. Text="{Binding ResourceType.DisplayName}" 064. Style="{StaticResource FormElementTextBlockStyle}" 065. Grid.Column="0" /> 066. <telerikInput:RadComboBox ItemsSource="{Binding ResourceItems}" 067. Width="185" 068. Margin="5,10,20,2" 069. HorizontalAlignment="Left" 070. Grid.Column="1" 071. ClearSelectionButtonVisibility="Visible" 072. ClearSelectionButtonContent="Clear All" 073. DisplayMemberPath="Resource.DisplayName" 074. telerik:StyleManager.Theme="{StaticResource Theme}" 075. SelectedItem="{Binding SelectedItem, Mode=TwoWay}" /> 076. </Grid> 077. </DataTemplate> 078. <DataTemplate x:Key="MultipleSelectionTemplate"> 079. <Grid VerticalAlignment="Stretch" 080. HorizontalAlignment="Stretch"> 081. <Grid.RowDefinitions> 082. <RowDefinition Height="Auto" /> 083. </Grid.RowDefinitions> 084. <Grid.ColumnDefinitions> 085. <ColumnDefinition Width="Auto" 086. MinWidth="84" /> 087. <ColumnDefinition Width="Auto" 088. MinWidth="200" /> 089. </Grid.ColumnDefinitions> 090. <TextBlock x:Name="SelectionNameLabel" 091. Grid.Column="0" 092. Text="{Binding ResourceType.DisplayName}" 093. Margin="0,13,4,2" 094. Style="{StaticResource FormElementTextBlockStyle}" /> 095. <telerikInput:RadComboBox Grid.Column="1" 096. Width="185" 097. HorizontalAlignment="Left" 098. Margin="5,10,20,2" 099. ItemsSource="{Binding ResourceItems}" 100. SelectedIndex="{Binding SelectedIndex, Mode=TwoWay}" 101. ClearSelectionButtonVisibility="Visible" 102. ClearSelectionButtonContent="Clear All" 103. telerik:StyleManager.Theme="{StaticResource Theme}"> 104. <telerikInput:RadComboBox.ItemTemplate> 105. <DataTemplate> 106. <Grid HorizontalAlignment="Stretch" 107. VerticalAlignment="Stretch"> 108. <CheckBox VerticalAlignment="Center" 109. HorizontalContentAlignment="Stretch" 110. VerticalContentAlignment="Center" 111. IsChecked="{Binding IsChecked, Mode=TwoWay}" 112. Content="{Binding Resource.DisplayName}"> 113. <CheckBox.ContentTemplate> 114. <DataTemplate> 115. <TextBlock HorizontalAlignment="Stretch" 116. VerticalAlignment="Stretch" 117. Text="{Binding Content, RelativeSource={RelativeSource TemplatedParent}}" /> 118. </DataTemplate> 119. </CheckBox.ContentTemplate> 120. </CheckBox> 121. </Grid> 122. </DataTemplate> 123. </telerikInput:RadComboBox.ItemTemplate> 124. </telerikInput:RadComboBox> 125. </Grid> 126. </DataTemplate> 127. <scheduler:ResourceTypeTemplateSelector x:Key="ItemTemplateSelector" 128. MultipleSelectionTemplate="{StaticResource MultipleSelectionTemplate}" 129. SingleSelectionTemplate="{StaticResource SingleSelectionTemplate}" /> 130.  131. 132. <ControlTemplate x:Key="EditAppointmentTemplate" 133. TargetType="telerikScheduler:AppointmentDialogWindow"> 134. <StackPanel Background="{TemplateBinding Background}" 135. UseLayoutRounding="True"> 136. <StackPanel Grid.Row="0" 137. Orientation="Horizontal" 138. Background="{StaticResource RadToolBar_InnerBackground}" 139. Grid.ColumnSpan="2" 140. Height="0"> 141.  142. <Border Margin="1,1,0,0" 143. Background="#50000000" 144. HorizontalAlignment="Left" 145. VerticalAlignment="Center" 146. Width="2" 147. Height="16"> 148. <Border Margin="0,0,1,1" 149. Background="#80FFFFFF" 150. HorizontalAlignment="Left" 151. Width="1" /> 152. </Border> 153. <Border Margin="1,1,0,0" 154. Background="#50000000" 155. HorizontalAlignment="Left" 156. VerticalAlignment="Center" 157. Width="2" 158. Height="16"> 159. <Border Margin="0,0,1,1" 160. Background="#80FFFFFF" 161. HorizontalAlignment="Left" 162. Width="1" /> 163. </Border> 164. <TextBlock telerik:LocalizationManager.ResourceKey="ShowAs" 165. VerticalAlignment="Center" 166. Margin="5,0,0,0" /> 167. <telerikInput:RadComboBox ItemsSource="{TemplateBinding TimeMarkers}" 168. Width="100" 169. Height="20" 170. VerticalAlignment="Center" 171. Margin="5,0,0,0" 172. ClearSelectionButtonVisibility="Visible" 173. ClearSelectionButtonContent="Clear" 174. SelectedItem="{Binding TimeMarker,RelativeSource={RelativeSource TemplatedParent},Mode=TwoWay}" 175. telerik:StyleManager.Theme="{StaticResource Theme}"> 176. <telerikInput:RadComboBox.ItemTemplate> 177. <DataTemplate> 178. <StackPanel Orientation="Horizontal"> 179. <Rectangle Fill="{Binding TimeMarkerBrush}" 180. Margin="2" 181. Width="12" 182. Height="12" /> 183. <TextBlock Text="{Binding TimeMarkerName}" 184. Margin="2" /> 185. </StackPanel> 186. </DataTemplate> 187. </telerikInput:RadComboBox.ItemTemplate> 188. </telerikInput:RadComboBox> 189. <telerik:RadToggleButton x:Name="High" 190. BorderThickness="0" 191. Background="{StaticResource RadToolBar_InnerBackground}" 192. DataContext="{TemplateBinding EditedAppointment}" 193. telerik:StyleManager.Theme="{StaticResource Theme}" 194. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=High}" 195. Margin="2,2,0,2" 196. Width="23" 197. Height="23" 198. HorizontalContentAlignment="Center" 199. ToolTipService.ToolTip="High importance" 200. CommandParameter="High" 201. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 202. <StackPanel HorizontalAlignment="Center"> 203. <Path Stretch="Fill" 204. Height="10" 205. HorizontalAlignment="Center" 206. VerticalAlignment="Top" 207. Width="5.451" 208. Data="M200.39647,58.840393 C200.39337,58.336426 201.14566,57.683922 202.56244,57.684292 C204.06589,57.684685 204.73764,58.357765 204.72783,58.992363 C205.04649,61.795574 203.04713,64.181099 202.47388,66.133446 C201.93753,64.154961 199.9471,61.560352 200.39647,58.840393 z"> 209. <Path.Fill> 210. <LinearGradientBrush EndPoint="1.059,0.375" 211. StartPoint="-0.457,0.519"> 212. <GradientStop Color="#FFFF0606" 213. Offset="0.609" /> 214. <GradientStop Color="#FFBF0303" 215. Offset="0.927" /> 216. </LinearGradientBrush> 217. </Path.Fill> 218. </Path> 219. <Ellipse Height="3" 220. HorizontalAlignment="Center" 221. Margin="0,-1,0,0" 222. VerticalAlignment="Top" 223. Width="3"> 224. <Ellipse.Fill> 225. <RadialGradientBrush> 226. <GradientStop Color="#FFFF0606" 227. Offset="0" /> 228. <GradientStop Color="#FFBF0303" 229. Offset="1" /> 230. </RadialGradientBrush> 231. </Ellipse.Fill> 232. </Ellipse> 233. </StackPanel> 234. </telerik:RadToggleButton> 235. <telerik:RadToggleButton x:Name="Low" 236. HorizontalContentAlignment="Center" 237. BorderThickness="0" 238. Background="{StaticResource RadToolBar_InnerBackground}" 239. DataContext="{TemplateBinding EditedAppointment}" 240. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=Low}" 241. Margin="0,2,0,2" 242. Width="23" 243. Height="23" 244. ToolTipService.ToolTip="Low importance" 245. CommandParameter="Low" 246. telerik:StyleManager.Theme="{StaticResource Theme}" 247. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 248. <Path Stretch="Fill" 249. Height="12" 250. HorizontalAlignment="Center" 251. VerticalAlignment="Top" 252. Width="9" 253. Data="M222.40353,60.139881 L226.65768,60.139843 L226.63687,67.240196 L229.15347,67.240196 L224.37816,71.394943 L219.65274,67.240196 L222.37572,67.219345 z" 254. Stroke="#FF0365A7"> 255. <Path.Fill> 256. <LinearGradientBrush EndPoint="1.059,0.375" 257. StartPoint="-0.457,0.519"> 258. <GradientStop Color="#FFBBE4FF" /> 259. <GradientStop Color="#FF024572" 260. Offset="0.836" /> 261. <GradientStop Color="#FF43ADF4" 262. Offset="0.466" /> 263. </LinearGradientBrush> 264. </Path.Fill> 265. </Path> 266. </telerik:RadToggleButton> 267. </StackPanel > 268. <Border DataContext="{TemplateBinding EditedAppointment}" 269. Background="{Binding Category.CategoryBrush}" 270. Visibility="{Binding Category,Converter={StaticResource NullToVisibilityConverter}}" 271. CornerRadius="3" 272. Height="20" 273. Margin="5,10,5,0"> 274. <TextBlock Text="{Binding Category.DisplayName}" 275. VerticalAlignment="Center" 276. Margin="5,0,0,0" /> 277. </Border> 278. <Grid VerticalAlignment="Stretch" 279. HorizontalAlignment="Stretch" 280. DataContext="{TemplateBinding EditedAppointment}" 281. Background="{TemplateBinding Background}"> 282. <Grid.RowDefinitions> 283. <RowDefinition Height="Auto" /> 284. <RowDefinition Height="Auto" /> 285. <RowDefinition Height="Auto" /> 286. <RowDefinition Height="Auto" /> 287. <RowDefinition Height="Auto" /> 288. <RowDefinition Height="Auto" /> 289. <RowDefinition Height="Auto" /> 290. <RowDefinition Height="Auto" /> 291. <RowDefinition Height="Auto" /> 292. <RowDefinition Height="Auto" /> 293. </Grid.RowDefinitions> 294. <Grid.ColumnDefinitions> 295. <ColumnDefinition Width="Auto" 296. MinWidth="100" /> 297. <ColumnDefinition Width="Auto" 298. MinWidth="200" /> 299. </Grid.ColumnDefinitions> 300.  301. <TextBlock x:Name="SubjectLabel" 302. Grid.Row="0" 303. Grid.Column="0" 304. Margin="0,15,0,2" 305. telerik:LocalizationManager.ResourceKey="Subject" 306. Style="{StaticResource FormElementTextBlockStyle}" /> 307. <TextBox x:Name="Subject" 308. Grid.Row="0" 309. Grid.Column="1" 310. MinHeight="22" 311. Padding="4 2" 312. Width="340" 313. HorizontalAlignment="Left" 314. Text="{Binding Subject, Mode=TwoWay}" 315. MaxLength="255" 316. telerik:StyleManager.Theme="{StaticResource Theme}" 317. Margin="10,12,20,2" /> 318.  319. <TextBlock x:Name="DescriptionLabel" 320. Grid.Row="1" 321. Grid.Column="0" 322. Margin="0,13,0,2" 323. telerik:LocalizationManager.ResourceKey="Body" 324. Style="{StaticResource FormElementTextBlockStyle}" /> 325. <TextBox x:Name="Body" 326. VerticalAlignment="top" 327. Grid.Row="1" 328. Grid.Column="1" 329. Height="Auto" 330. MaxHeight="82" 331. Width="340" 332. HorizontalAlignment="Left" 333. MinHeight="22" 334. Padding="4 2" 335. TextWrapping="Wrap" 336. telerik:StyleManager.Theme="{StaticResource Theme}" 337. Text="{Binding Body, Mode=TwoWay}" 338. AcceptsReturn="true" 339. Margin="10,10,20,2" 340. HorizontalScrollBarVisibility="Auto" 341. VerticalScrollBarVisibility="Auto" /> 342.  343. <TextBlock x:Name="StartDateLabel" 344. Grid.Row="2" 345. Grid.Column="0" 346. Margin="0,13,0,2" 347. telerik:LocalizationManager.ResourceKey="StartTime" 348. Style="{StaticResource FormElementTextBlockStyle}" /> 349. <telerikScheduler:DateTimePicker x:Name="StartDateTime" 350. Height="22" 351. Grid.Row="2" 352. Grid.Column="1" 353. HorizontalAlignment="Left" 354. Margin="10,10,20,2" 355. Style="{StaticResource FormElementStyle}" 356. SelectedDateTime="{Binding Start, Mode=TwoWay}" 357. telerikScheduler:StartEndDatePicker.EndPicker="{Binding ElementName=EndDateTime}" 358. IsTabStop="False" 359. IsEnabled="False" /> 360. <TextBlock x:Name="EndDateLabel" 361. Grid.Row="3" 362. Grid.Column="0" 363. Margin="0,13,0,2" 364. telerik:LocalizationManager.ResourceKey="EndTime" 365. Style="{StaticResource FormElementTextBlockStyle}" /> 366. <telerikScheduler:DateTimePicker x:Name="EndDateTime" 367. Height="22" 368. Grid.Row="3" 369. Grid.Column="1" 370. HorizontalAlignment="Left" 371. Margin="10,10,20,2" 372. Style="{StaticResource FormElementStyle}" 373. IsTabStop="False" 374. IsEnabled="False" 375. SelectedDateTime="{Binding End, Mode=TwoWay}" /> 376.  377. <CheckBox x:Name="AllDayEventCheckbox" 378. IsChecked="{Binding IsAllDayEvent, Mode=TwoWay}" 379. Grid.Row="4" 380. Grid.Column="1" 381. Margin="10,10,20,2" 382. HorizontalAlignment="Left" 383. telerik:StyleManager.Theme="{StaticResource Theme}" 384. telerik:LocalizationManager.ResourceKey="AllDayEvent"> 385. <telerik:CommandManager.InputBindings> 386. <telerik:InputBindingCollection> 387. <telerik:MouseBinding Command="telerikScheduler:RadSchedulerCommands.ChangeTimePickersVisibility" 388. Gesture="LeftClick" /> 389. </telerik:InputBindingCollection> 390. </telerik:CommandManager.InputBindings> 391. </CheckBox> 392. <Grid Grid.Row="5" 393. Grid.ColumnSpan="2"> 394. <Grid.ColumnDefinitions> 395. <ColumnDefinition Width="Auto" 396. MinWidth="100" /> 397. <ColumnDefinition Width="Auto" 398. MinWidth="200" /> 399. </Grid.ColumnDefinitions> 400. <Grid.RowDefinitions> 401. <RowDefinition Height="Auto" /> 402. <RowDefinition Height="Auto" /> 403. </Grid.RowDefinitions> 404. <TextBlock Text="Applicant" 405. Margin="0,13,0,2" 406. Style="{StaticResource FormElementTextBlockStyle}" /> 407. <telerikInput:RadComboBox IsEditable="False" 408. Grid.Column="1" 409. Height="24" 410. VerticalAlignment="Center" 411. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.ApplicantList}" 412. SelectedValue="{Binding ApplicantID, Mode=TwoWay}" 413. SelectedValuePath="ApplicantID" 414. DisplayMemberPath="FirstName" /> 415. 416. <TextBlock Text="Job" 417. Margin="0,13,0,2" 418. Grid.Row="1" 419. Style="{StaticResource FormElementTextBlockStyle}" /> 420. <telerikInput:RadComboBox IsEditable="False" 421. Grid.Column="1" 422. Grid.Row="1" 423. Height="24" 424. VerticalAlignment="Center" 425. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.JobsList}" 426. SelectedValue="{Binding PostingID, Mode=TwoWay}" 427. SelectedValuePath="PostingID" 428. DisplayMemberPath="JobTitle"/> 429. </Grid> 430.  431. <Grid x:Name="ResourcesLayout" 432. Grid.Row="7" 433. Grid.Column="0" 434. Grid.ColumnSpan="2" 435. MaxHeight="130" 436. Margin="20,5,20,0"> 437. <Border Margin="0" 438. BorderThickness="1" 439. BorderBrush="{StaticResource GenericShallowBorderBrush}" 440. Visibility="{Binding ElementName=ResourcesScrollViewer, Path=ComputedVerticalScrollBarVisibility}"></Border> 441. <ScrollViewer x:Name="ResourcesScrollViewer" 442. IsTabStop="false" 443. Grid.Row="6" 444. Grid.Column="0" 445. Grid.ColumnSpan="2" 446. Margin="1" 447. telerik:StyleManager.Theme="{StaticResource Theme}" 448. VerticalScrollBarVisibility="Auto"> 449. <scheduler:ResourcesItemsControl x:Name="PART_Resources" 450. HorizontalAlignment="Left" 451. Padding="0,2,0,5" 452. IsTabStop="false" 453. ItemsSource="{TemplateBinding ResourceTypeModels}" 454. ItemTemplateSelector="{StaticResource ItemTemplateSelector}" /> 455. </ScrollViewer> 456. </Grid> 457. <StackPanel x:Name="FooterControls" 458. Margin="5 10 10 10" 459. Grid.Row="8" 460. Grid.Column="1" 461. HorizontalAlignment="Left" 462. Orientation="Horizontal"> 463. <telerik:RadButton x:Name="OKButton" 464. Margin="5" 465. Padding="10 0" 466. MinWidth="80" 467. Command="telerikScheduler:RadSchedulerCommands.SaveAppointment" 468. telerik:StyleManager.Theme="{StaticResource Theme}" 469. telerikNavigation:RadWindow.ResponseButton="Accept" 470. telerik:LocalizationManager.ResourceKey="SaveAndCloseCommandText"> 471. </telerik:RadButton> 472. <telerik:RadButton x:Name="CancelButton" 473. Margin="5" 474. Padding="10 0" 475. MinWidth="80" 476. telerik:LocalizationManager.ResourceKey="Cancel" 477. telerik:StyleManager.Theme="{StaticResource Theme}" 478. telerikNavigation:RadWindow.ResponseButton="Cancel" 479. Command="telerik:WindowCommands.Close"> 480. </telerik:RadButton> 481. </StackPanel> 482. </Grid> 483. <vsm:VisualStateManager.VisualStateGroups> 484. <vsm:VisualStateGroup x:Name="RecurrenceRuleState"> 485. <vsm:VisualState x:Name="RecurrenceRuleIsNull"> 486. <Storyboard> 487. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 488. Storyboard.TargetProperty="IsEnabled" 489. Duration="0"> 490. <DiscreteObjectKeyFrame KeyTime="0" 491. Value="True" /> 492. </ObjectAnimationUsingKeyFrames> 493. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 494. Storyboard.TargetProperty="IsEnabled" 495. Duration="0"> 496. <DiscreteObjectKeyFrame KeyTime="0" 497. Value="True" /> 498. </ObjectAnimationUsingKeyFrames> 499. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 500. Storyboard.TargetProperty="IsEnabled" 501. Duration="0"> 502. <DiscreteObjectKeyFrame KeyTime="0" 503. Value="True" /> 504. </ObjectAnimationUsingKeyFrames> 505. </Storyboard> 506. </vsm:VisualState> 507. <vsm:VisualState x:Name="RecurrenceRuleIsNotNull"> 508. <Storyboard> 509. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 510. Storyboard.TargetProperty="IsEnabled" 511. Duration="0"> 512. <DiscreteObjectKeyFrame KeyTime="0" 513. Value="False" /> 514. </ObjectAnimationUsingKeyFrames> 515. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 516. Storyboard.TargetProperty="IsEnabled" 517. Duration="0"> 518. <DiscreteObjectKeyFrame KeyTime="0" 519. Value="False" /> 520. </ObjectAnimationUsingKeyFrames> 521. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 522. Storyboard.TargetProperty="IsEnabled" 523. Duration="0"> 524. <DiscreteObjectKeyFrame KeyTime="0" 525. Value="False" /> 526. </ObjectAnimationUsingKeyFrames> 527. </Storyboard> 528. </vsm:VisualState> 529. </vsm:VisualStateGroup> 530. </vsm:VisualStateManager.VisualStateGroups> 531. </StackPanel> 532. </ControlTemplate> 533. <DataTemplate x:Key="AppointmentDialogWindowHeaderDataTemplate"> 534. <StackPanel Orientation="Horizontal" 535. MaxWidth="400"> 536. <TextBlock telerik:LocalizationManager.ResourceKey="Event" 537. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource BooleanToVisibilityConverter}}" /> 538. <TextBlock telerik:LocalizationManager.ResourceKey="Appointment" 539. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource InvertedBooleanToVisibilityConverter}}" /> 540. <TextBlock Text=" - " /> 541. <TextBlock x:Name="SubjectTextBlock" 542. Visibility="{Binding Appointment.Subject, Converter={StaticResource NullToVisibilityConverter}}" 543. Text="{Binding Appointment.Subject}" /> 544. <TextBlock telerik:LocalizationManager.ResourceKey="Untitled" 545. Visibility="{Binding Appointment.Subject, Converter={StaticResource InvertedNullToVisibilityConverter}}" /> 546. </StackPanel> 547. </DataTemplate> 548. <Style x:Key="EditAppointmentStyle" 549. TargetType="telerikScheduler:AppointmentDialogWindow"> 550. <Setter Property="IconTemplate" 551. Value="{StaticResource IconDataEditTemplate}" /> 552. <Setter Property="HeaderTemplate" 553. Value="{StaticResource AppointmentDialogWindowHeaderDataTemplate}" /> 554. <Setter Property="Background" 555. Value="{StaticResource DialogWindowBackground}" /> 556. <Setter Property="Template" 557. Value="{StaticResource EditAppointmentTemplate}" /> 558. </Style> 559.</UserControl.Resources> The first line there is the DataContextProxy I mentioned previously- we use that again to work a bit of magic in this template. Where we start getting into the dialog in question is line 132, but line 407 is where things start getting interesting. The ItemsSource is pointing at a list that exists in my ViewModel (or code-behind, if it is used as a DataContext), the SelectedValue is the item I am actually binding from the applicant (note the TwoWay binding), and SelectedValuePath and DisplayMemberPath ensure the proper applicant is being displayed from the collection. You will also see similar starting on line 420 where I do the same for the Jobs we'll be displaying. Just to wrap-up the Xaml, here's the RadScheduler declaraction that ties this all together and will be the main focus of our view: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. AppointmentsSource="{Binding Interviews}" 09. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 10. command:AppointmentAddedEventClass.Command="{Binding AddAppointmentCommand}" 11. command:ApptCreatedEventClass.Command="{Binding ApptCreatingCommand}" 12. command:ApptEditedEventClass.Command="{Binding ApptEditedCommand}" 13. command:ApptDeletedEventClass.Command="{Binding ApptDeletedCommand}"> 14.</telerikScheduler:RadScheduler> Now, we get to the ViewModel and what it takes to get that rigged up. And for those of you who remember the jobs post, those command:s in the Xaml are pointing to attached behavior commands that reproduce the respective events. This becomes very handy when we're setting up the code-behind version. ;) ViewModel I've been liking this approach so far, so I'm going to put the entire ViewModel here and then go into the lines of interest. Of course, feel free to ask me questions about anything that isn't clear (by line number, ideally) so I can help out if I have missed anything important: 001.public class SchedulerViewModel : ViewModelBase 002.{ 003. private readonly IEventAggregator eventAggregator; 004. private readonly IRegionManager regionManager; 005. 006. public RecruitingContext context; 007. 008. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 009. public ObservableItemCollection<InterviewAppointment> Interviews 010. { 011. get { return _interviews; } 012. set 013. { 014. if (_interviews != value) 015. { 016. _interviews = value; 017. NotifyChanged("Interviews"); 018. } 019. } 020. } 021. 022. private QueryableCollectionView _jobsList; 023. public QueryableCollectionView JobsList 024. { 025. get { return this._jobsList; } 026. set 027. { 028. if (this._jobsList != value) 029. { 030. this._jobsList = value; 031. this.NotifyChanged("JobsList"); 032. } 033. } 034. } 035. 036. private QueryableCollectionView _applicantList; 037. public QueryableCollectionView ApplicantList 038. { 039. get { return _applicantList; } 040. set 041. { 042. if (_applicantList != value) 043. { 044. _applicantList = value; 045. NotifyChanged("ApplicantList"); 046. } 047. } 048. } 049. 050. public DelegateCommand<object> AddAppointmentCommand { get; set; } 051. public DelegateCommand<object> ApptCreatingCommand { get; set; } 052. public DelegateCommand<object> ApptEditedCommand { get; set; } 053. public DelegateCommand<object> ApptDeletedCommand { get; set; } 054. 055. public SchedulerViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 056. { 057. // set Unity items 058. this.eventAggregator = eventAgg; 059. this.regionManager = regionmanager; 060. 061. // load our context 062. context = new RecruitingContext(); 063. LoadOperation<Interview> loadOp = context.Load(context.GetInterviewsQuery()); 064. loadOp.Completed += new EventHandler(loadOp_Completed); 065. 066. this._jobsList = new QueryableCollectionView(context.JobPostings); 067. context.Load(context.GetJobPostingsQuery()); 068. 069. this._applicantList = new QueryableCollectionView(context.Applicants); 070. context.Load(context.GetApplicantsQuery()); 071. 072. AddAppointmentCommand = new DelegateCommand<object>(this.AddAppt); 073. ApptCreatingCommand = new DelegateCommand<object>(this.ApptCreating); 074. ApptEditedCommand = new DelegateCommand<object>(this.ApptEdited); 075. ApptDeletedCommand = new DelegateCommand<object>(this.ApptDeleted); 076. 077. } 078. 079. void loadOp_Completed(object sender, EventArgs e) 080. { 081. LoadOperation loadop = sender as LoadOperation; 082. 083. foreach (var ent in loadop.Entities) 084. { 085. _interviews.Add(EntityToAppointment(ent as Interview)); 086. } 087. } 088. 089. #region Appointment Adding 090. 091. public void AddAppt(object obj) 092. { 093. // now we have a new InterviewAppointment to add to our QCV :) 094. InterviewAppointment newInterview = obj as InterviewAppointment; 095. 096. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 097. this.context.SubmitChanges((s) => 098. { 099. ActionHistory myAction = new ActionHistory(); 100. myAction.InterviewID = newInterview.InterviewID; 101. myAction.PostingID = newInterview.PostingID; 102. myAction.ApplicantID = newInterview.ApplicantID; 103. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 104. myAction.TimeStamp = DateTime.Now; 105. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 106. } 107. , null); 108. } 109. 110. public void ApptCreating(object obj) 111. { 112. // handled in the behavior, just a placeholder to ensure it runs :) 113. } 114. 115. #endregion 116. 117. #region Appointment Editing 118. 119. public void ApptEdited(object obj) 120. { 121. Interview editedInterview = (from x in context.Interviews 122. where x.InterviewID == (obj as InterviewAppointment).InterviewID 123. select x).SingleOrDefault(); 124. 125. CopyAppointmentEdit(editedInterview, obj as InterviewAppointment); 126. 127. context.SubmitChanges((s) => { 128. ActionHistory myAction = new ActionHistory(); 129. myAction.InterviewID = editedInterview.InterviewID; 130. myAction.PostingID = editedInterview.PostingID; 131. myAction.ApplicantID = editedInterview.ApplicantID; 132. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 133. myAction.TimeStamp = DateTime.Now; 134. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); } 135. , null); 136. } 137. 138. #endregion 139. 140. #region Appointment Deleting 141. 142. public void ApptDeleted(object obj) 143. { 144. Interview deletedInterview = (from x in context.Interviews 145. where x.InterviewID == (obj as InterviewAppointment).InterviewID 146. select x).SingleOrDefault(); 147. 148. context.Interviews.Remove(deletedInterview); 149. context.SubmitChanges((s) => 150. { 151. ActionHistory myAction = new ActionHistory(); 152. myAction.InterviewID = deletedInterview.InterviewID; 153. myAction.PostingID = deletedInterview.PostingID; 154. myAction.ApplicantID = deletedInterview.ApplicantID; 155. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 156. myAction.TimeStamp = DateTime.Now; 157. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 158. } 159. , null); 160. } 161. 162. #endregion 163. 164. #region Appointment Helpers :) 165. 166. public Interview AppointmentToEntity(InterviewAppointment ia) 167. { 168. Interview newInterview = new Interview(); 169. newInterview.Subject = ia.Subject; 170. newInterview.Body = ia.Body; 171. newInterview.Start = ia.Start; 172. newInterview.End = ia.End; 173. newInterview.ApplicantID = ia.ApplicantID; 174. newInterview.PostingID = ia.PostingID; 175. newInterview.InterviewID = ia.InterviewID; 176. 177. return newInterview; 178. } 179. 180. public InterviewAppointment EntityToAppointment(Interview ia) 181. { 182. InterviewAppointment newInterview = new InterviewAppointment(); 183. newInterview.Subject = ia.Subject; 184. newInterview.Body = ia.Body; 185. newInterview.Start = ia.Start; 186. newInterview.End = ia.End; 187. newInterview.ApplicantID = ia.ApplicantID; 188. newInterview.PostingID = ia.PostingID; 189. newInterview.InterviewID = ia.InterviewID; 190. 191. return newInterview; 192. } 193. 194. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 195. { 196. entityInterview.Subject = appointmentInterview.Subject; 197. entityInterview.Body = appointmentInterview.Body; 198. entityInterview.Start = appointmentInterview.Start; 199. entityInterview.End = appointmentInterview.End; 200. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 201. entityInterview.PostingID = appointmentInterview.PostingID; 202. } 203. 204. #endregion 205.} One thing we're doing here which you won't see in any of the other ViewModels is creating a duplicate collection. I know this is something which will be fixed down the line for using RadScheduler, simplifying this process, but with WCF RIA changing as it does I wanted to ensure functionality would remain consistent as I continued development on this application. So, I do a little bit of duplication, but for the greater good. This all takes place starting on line 79, so for every entity that comes back we add it to the collection that is bound to RadScheduler. Otherwise, the DelegateCommands that you see correspond directly to the events they are named after. In each case, rather than sending over the full event arguments, I just send in the appointment in question (coming through as the object obj in all cases) so I can add (line 91), edit (line 119), and delete appointments (line 142) like normal. This just ensures they get updated back to my database. Also, the one bit of code you won't see is for the Appointment Creating (line 110) event- that is because in the command I've created I simply make the replacement I need to: 1.void element_AppointmentCreating(object sender, AppointmentCreatingEventArgs e) 2.{ 3. e.NewAppointment = new InterviewAppointment(); 4. base.ExecuteCommand(); 5.} And the ViewModel is none the wiser, the appointments just work as far as it is concerned since as they are created they become InterviewAppointments. End result? I've customized my EditAppointmentDialog as follows: And adding, editing, and deleting appointments works like a charm. I can even 'edit' by moving appointments around RadScheduler, so as they are dropped into a timeslot they perform their full edit routine and things get updated. And then, the Code-Behind Version Perhaps the thing I like the most about doing one then the other is I get to steal 90% or more of the code from the MVVM version. For example, the only real changes to the Code-Behind Xaml file exist in the control declaration, in which I use events instead of attached-behavior-event-commands: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 09. AppointmentAdded="xJobsScheduler_AppointmentAdded" 10. AppointmentCreating="xJobsScheduler_AppointmentCreating" 11. AppointmentEdited="xJobsScheduler_AppointmentEdited" 12. AppointmentDeleted="xJobsScheduler_AppointmentDeleted"> 13.</telerikScheduler:RadScheduler> Easy, right? Otherwise, all the same styling in UserControl.Resources was re-used, right down to the DataContextProxy that lets us bind to a collection from our viewmodel (in this case, our code-behind) to use within the DataTemplate. The code conversion gets even easier, as I could literally copy and paste almost everything from the ViewModel to my Code-Behind, just a matter of pasting the right section into the right event. Here's the code-behind as proof: 001.public partial class SchedulingView : UserControl, INotifyPropertyChanged 002.{ 003. public RecruitingContext context; 004. 005. private QueryableCollectionView _jobsList; 006. public QueryableCollectionView JobsList 007. { 008. get { return this._jobsList; } 009. set 010. { 011. if (this._jobsList != value) 012. { 013. this._jobsList = value; 014. this.NotifyChanged("JobsList"); 015. } 016. } 017. } 018. 019. private QueryableCollectionView _applicantList; 020. public QueryableCollectionView ApplicantList 021. { 022. get { return _applicantList; } 023. set 024. { 025. if (_applicantList != value) 026. { 027. _applicantList = value; 028. NotifyChanged("ApplicantList"); 029. } 030. } 031. } 032. 033. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 034. public ObservableItemCollection<InterviewAppointment> Interviews 035. { 036. get { return _interviews; } 037. set 038. { 039. if (_interviews != value) 040. { 041. _interviews = value; 042. NotifyChanged("Interviews"); 043. } 044. } 045. } 046. 047. public SchedulingView() 048. { 049. InitializeComponent(); 050. 051. this.DataContext = this; 052. 053. this.Loaded += new RoutedEventHandler(SchedulingView_Loaded); 054. } 055. 056. void SchedulingView_Loaded(object sender, RoutedEventArgs e) 057. { 058. this.xJobsScheduler.AppointmentsSource = Interviews; 059. 060. context = new RecruitingContext(); 061. 062. LoadOperation loadop = context.Load(context.GetInterviewsQuery()); 063. loadop.Completed += new EventHandler(loadop_Completed); 064. 065. this._applicantList = new QueryableCollectionView(context.Applicants); 066. context.Load(context.GetApplicantsQuery()); 067. 068. this._jobsList = new QueryableCollectionView(context.JobPostings); 069. context.Load(context.GetJobPostingsQuery()); 070. } 071. 072. void loadop_Completed(object sender, EventArgs e) 073. { 074. LoadOperation loadop = sender as LoadOperation; 075. 076. _interviews.Clear(); 077. 078. foreach (var ent in loadop.Entities) 079. { 080. _interviews.Add(EntityToAppointment(ent as Interview)); 081. } 082. } 083. 084. private void xJobsScheduler_AppointmentAdded(object sender, Telerik.Windows.Controls.AppointmentAddedEventArgs e) 085. { 086. // now we have a new InterviewAppointment to add to our QCV :) 087. InterviewAppointment newInterview = e.Appointment as InterviewAppointment; 088. 089. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 090. this.context.SubmitChanges((s) => 091. { 092. ActionHistory myAction = new ActionHistory(); 093. myAction.InterviewID = newInterview.InterviewID; 094. myAction.PostingID = newInterview.PostingID; 095. myAction.ApplicantID = newInterview.ApplicantID; 096. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 097. myAction.TimeStamp = DateTime.Now; 098. context.ActionHistories.Add(myAction); 099. context.SubmitChanges(); 100. } 101. , null); 102. } 103. 104. private void xJobsScheduler_AppointmentCreating(object sender, Telerik.Windows.Controls.AppointmentCreatingEventArgs e) 105. { 106. e.NewAppointment = new InterviewAppointment(); 107. } 108. 109. private void xJobsScheduler_AppointmentEdited(object sender, Telerik.Windows.Controls.AppointmentEditedEventArgs e) 110. { 111. Interview editedInterview = (from x in context.Interviews 112. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 113. select x).SingleOrDefault(); 114. 115. CopyAppointmentEdit(editedInterview, e.Appointment as InterviewAppointment); 116. 117. context.SubmitChanges((s) => 118. { 119. ActionHistory myAction = new ActionHistory(); 120. myAction.InterviewID = editedInterview.InterviewID; 121. myAction.PostingID = editedInterview.PostingID; 122. myAction.ApplicantID = editedInterview.ApplicantID; 123. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 124. myAction.TimeStamp = DateTime.Now; 125. context.ActionHistories.Add(myAction); 126. context.SubmitChanges(); 127. } 128. , null); 129. } 130. 131. private void xJobsScheduler_AppointmentDeleted(object sender, Telerik.Windows.Controls.AppointmentDeletedEventArgs e) 132. { 133. Interview deletedInterview = (from x in context.Interviews 134. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 135. select x).SingleOrDefault(); 136. 137. context.Interviews.Remove(deletedInterview); 138. context.SubmitChanges((s) => 139. { 140. ActionHistory myAction = new ActionHistory(); 141. myAction.InterviewID = deletedInterview.InterviewID; 142. myAction.PostingID = deletedInterview.PostingID; 143. myAction.ApplicantID = deletedInterview.ApplicantID; 144. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 145. myAction.TimeStamp = DateTime.Now; 146. context.ActionHistories.Add(myAction); 147. context.SubmitChanges(); 148. } 149. , null); 150. } 151. 152. #region Appointment Helpers :) 153. 154. public Interview AppointmentToEntity(InterviewAppointment ia) 155. { 156. Interview newInterview = new Interview(); 157. newInterview.Subject = ia.Subject; 158. newInterview.Body = ia.Body; 159. newInterview.Start = ia.Start; 160. newInterview.End = ia.End; 161. newInterview.ApplicantID = ia.ApplicantID; 162. newInterview.PostingID = ia.PostingID; 163. newInterview.InterviewID = ia.InterviewID; 164. 165. return newInterview; 166. } 167. 168. public InterviewAppointment EntityToAppointment(Interview ia) 169. { 170. InterviewAppointment newInterview = new InterviewAppointment(); 171. newInterview.Subject = ia.Subject; 172. newInterview.Body = ia.Body; 173. newInterview.Start = ia.Start; 174. newInterview.End = ia.End; 175. newInterview.ApplicantID = ia.ApplicantID; 176. newInterview.PostingID = ia.PostingID; 177. newInterview.InterviewID = ia.InterviewID; 178. 179. return newInterview; 180. } 181. 182. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 183. { 184. entityInterview.Subject = appointmentInterview.Subject; 185. entityInterview.Body = appointmentInterview.Body; 186. entityInterview.Start = appointmentInterview.Start; 187. entityInterview.End = appointmentInterview.End; 188. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 189. entityInterview.PostingID = appointmentInterview.PostingID; 190. } 191. 192. #endregion 193. 194. #region INotifyPropertyChanged Members 195. 196. public event PropertyChangedEventHandler PropertyChanged; 197. 198. public void NotifyChanged(string propertyName) 199. { 200. if (string.IsNullOrEmpty(propertyName)) 201. throw new ArgumentException("propertyName"); 202. 203. PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 204. } 205. 206. #endregion 207.} Nice... right? :) One really important thing to note as well. See on line 51 where I set the DataContext before the Loaded event? This is super important, as if you don't have this set before the usercontrol is loaded, the DataContextProxy has no context to use and your EditAppointmentDialog Job/Applicant dropdowns will be blank and empty. Trust me on this, took a little bit of debugging to figure out that by setting the DataContext post-loaded would only lead to disaster and frustration. Otherwise, the only other real difference is that instead of sending an ActionHistory item through an event to get added to the database and saved, I do those right in the callback from submitting. The Result Again, I only have to post one picture because these bad boys used nearly identical code for both the MVVM and the code-behind views, so our end result is... So what have we learned here today? One, for the most part this MVVM thing is somewhat easy. Yeah, you sometimes have to write a bunch of extra code, but with the help of a few useful snippits you can turn the process into a pretty streamlined little workflow. Heck, this story gets even easier as you can see in this blog post by Michael Washington- specifically run a find on 'InvokeCommandAction' and you'll see the section regarding the command on TreeView in Blend 4. Brilliant! MVVM never looked so sweet! Otherwise, it is business as usual with RadScheduler for Silverlight whichever path you're choosing for your development. Between now and the next post, I'll be cleaning up styles a bit (those RadComboBoxes are a little too close to my labels!) and adding some to the RowDetailsViews for Applicants and Jobs, so you can see all the info for an appointment in the dropdown tab view. Otherwise, we're about ready to call a wrap on this oneDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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AngularJS on top of ASP.NET: Moving the MVC framework out to the browser

- by Varun Chatterji

Heavily drawing inspiration from Ruby on Rails, MVC4’s convention over configuration model of development soon became the Holy Grail of .NET web development. The MVC model brought with it the goodness of proper separation of concerns between business logic, data, and the presentation logic. However, the MVC paradigm, was still one in which server side .NET code could be mixed with presentation code. The Razor templating engine, though cleaner than its predecessors, still encouraged and allowed you to mix .NET server side code with presentation logic. Thus, for example, if the developer required a certain <div> tag to be shown if a particular variable ShowDiv was true in the View’s model, the code could look like the following: Fig 1: To show a div or not. Server side .NET code is used in the View Mixing .NET code with HTML in views can soon get very messy. Wouldn’t it be nice if the presentation layer (HTML) could be pure HTML? Also, in the ASP.NET MVC model, some of the business logic invariably resides in the controller. It is tempting to use an antipattern like the one shown above to control whether a div should be shown or not. However, best practice would indicate that the Controller should not be aware of the div. The ShowDiv variable in the model should not exist. A controller should ideally, only be used to do the plumbing of getting the data populated in the model and nothing else. The view (ideally pure HTML) should render the presentation layer based on the model. In this article we will see how Angular JS, a new JavaScript framework by Google can be used effectively to build web applications where: 1. Views are pure HTML 2. Controllers (in the server sense) are pure REST based API calls 3. The presentation layer is loaded as needed from partial HTML only files. What is MVVM? MVVM short for Model View View Model is a new paradigm in web development. In this paradigm, the Model and View stuff exists on the client side through javascript instead of being processed on the server through postbacks. These frameworks are JavaScript frameworks that facilitate the clear separation of the “frontend” or the data rendering logic from the “backend” which is typically just a REST based API that loads and processes data through a resource model. The frameworks are called MVVM as a change to the Model (through javascript) gets reflected in the view immediately i.e. Model > View. Also, a change on the view (through manual input) gets reflected in the model immediately i.e. View > Model. The following figure shows this conceptually (comments are shown in red): Fig 2: Demonstration of MVVM in action In Fig 2, two text boxes are bound to the same variable model.myInt. Thus, changing the view manually (changing one text box through keyboard input) also changes the other textbox in real time demonstrating V > M property of a MVVM framework. Furthermore, clicking the button adds 1 to the value of model.myInt thus changing the model through JavaScript. This immediately updates the view (the value in the two textboxes) thus demonstrating the M > V property of a MVVM framework. Thus we see that the model in a MVVM JavaScript framework can be regarded as “the single source of truth“. This is an important concept. Angular is one such MVVM framework. We shall use it to build a simple app that sends SMS messages to a particular number. Application, Routes, Views, Controllers, Scope and Models Angular can be used in many ways to construct web applications. For this article, we shall only focus on building Single Page Applications (SPAs). Many of the approaches we will follow in this article have alternatives. It is beyond the scope of this article to explain every nuance in detail but we shall try to touch upon the basic concepts and end up with a working application that can be used to send SMS messages using Sent.ly Plus (a service that is itself built using Angular). Before you read on, we would like to urge you to forget what you know about Models, Views, Controllers and Routes in the ASP.NET MVC4 framework. All these words have different meanings in the Angular world. Whenever these words are used in this article, they will refer to Angular concepts and not ASP.NET MVC4 concepts. The following figure shows the skeleton of the root page of an SPA: Fig 3: The skeleton of a SPA The skeleton of the application is based on the Bootstrap starter template which can be found at: http://getbootstrap.com/examples/startertemplate/ Apart from loading the Angular, jQuery and Bootstrap JavaScript libraries, it also loads our custom scripts /app/js/controllers.js /app/js/app.js These scripts define the routes, views and controllers which we shall come to in a moment. Application Notice that the body tag (Fig. 3) has an extra attribute: ngapp=”smsApp” Providing this tag “bootstraps” our single page application. It tells Angular to load a “module” called smsApp. This “module” is defined /app/js/app.js angular.module('smsApp', ['smsApp.controllers', function () {}]) Fig 4: The definition of our application module The line shows above, declares a module called smsApp. It also declares that this module “depends” on another module called “smsApp.controllers”. The smsApp.controllers module will contain all the controllers for our SPA. Routing and Views Notice that in the Navbar (in Fig 3) we have included two hyperlinks to: “#/app” “#/help” This is how Angular handles routing. Since the URLs start with “#”, they are actually just bookmarks (and not server side resources). However, our route definition (in /app/js/app.js) gives these URLs a special meaning within the Angular framework. angular.module('smsApp', ['smsApp.controllers', function () { }]) //Configure the routes .config(['$routeProvider', function ($routeProvider) { $routeProvider.when('/binding', { templateUrl: '/app/partials/bindingexample.html', controller: 'BindingController' }); }]); Fig 5: The definition of a route with an associated partial view and controller As we can see from the previous code sample, we are using the $routeProvider object in the configuration of our smsApp module. Notice how the code “asks for” the $routeProvider object by specifying it as a dependency in the [] braces and then defining a function that accepts it as a parameter. This is known as dependency injection. Please refer to the following link if you want to delve into this topic: http://docs.angularjs.org/guide/di What the above code snippet is doing is that it is telling Angular that when the URL is “#/binding”, then it should load the HTML snippet (“partial view”) found at /app/partials/bindingexample.html. Also, for this URL, Angular should load the controller called “BindingController”. We have also marked the div with the class “container” (in Fig 3) with the ngview attribute. This attribute tells Angular that views (partial HTML pages) defined in the routes will be loaded within this div. You can see that the Angular JavaScript framework, unlike many other frameworks, works purely by extending HTML tags and attributes. It also allows you to extend HTML with your own tags and attributes (through directives) if you so desire, you can find out more about directives at the following URL: http://www.codeproject.com/Articles/607873/ExtendingHTMLwithAngularJSDirectives Controllers and Models We have seen how we define what views and controllers should be loaded for a particular route. Let us now consider how controllers are defined. Our controllers are defined in the file /app/js/controllers.js. The following snippet shows the definition of the “BindingController” which is loaded when we hit the URL http://localhost:port/index.html#/binding (as we have defined in the route earlier as shown in Fig 5). Remember that we had defined that our application module “smsApp” depends on the “smsApp.controllers” module (see Fig 4). The code snippet below shows how the “BindingController” defined in the route shown in Fig 5 is defined in the module smsApp.controllers: angular.module('smsApp.controllers', [function () { }]) .controller('BindingController', ['$scope', function ($scope) { $scope.model = {}; $scope.model.myInt = 6; $scope.addOne = function () { $scope.model.myInt++; } }]); Fig 6: The definition of a controller in the “smsApp.controllers” module. The pieces are falling in place! Remember Fig.2? That was the code of a partial view that was loaded within the container div of the skeleton SPA shown in Fig 3. The route definition shown in Fig 5 also defined that the controller called “BindingController” (shown in Fig 6.) was loaded when we loaded the URL: http://localhost:22544/index.html#/binding The button in Fig 2 was marked with the attribute ngclick=”addOne()” which added 1 to the value of model.myInt. In Fig 6, we can see that this function is actually defined in the “BindingController”. Scope We can see from Fig 6, that in the definition of “BindingController”, we defined a dependency on $scope and then, as usual, defined a function which “asks for” $scope as per the dependency injection pattern. So what is $scope? Any guesses? As you might have guessed a scope is a particular “address space” where variables and functions may be defined. This has a similar meaning to scope in a programming language like C#. Model: The Scope is not the Model It is tempting to assign variables in the scope directly. For example, we could have defined myInt as $scope.myInt = 6 in Fig 6 instead of $scope.model.myInt = 6. The reason why this is a bad idea is that scope in hierarchical in Angular. Thus if we were to define a controller which was defined within the another controller (nested controllers), then the inner controller would inherit the scope of the parent controller. This inheritance would follow JavaScript prototypal inheritance. Let’s say the parent controller defined a variable through $scope.myInt = 6. The child controller would inherit the scope through java prototypical inheritance. This basically means that the child scope has a variable myInt that points to the parent scopes myInt variable. Now if we assigned the value of myInt in the parent, the child scope would be updated with the same value as the child scope’s myInt variable points to the parent scope’s myInt variable. However, if we were to assign the value of the myInt variable in the child scope, then the link of that variable to the parent scope would be broken as the variable myInt in the child scope now points to the value 6 and not to the parent scope’s myInt variable. But, if we defined a variable model in the parent scope, then the child scope will also have a variable model that points to the model variable in the parent scope. Updating the value of $scope.model.myInt in the parent scope would change the model variable in the child scope too as the variable is pointed to the model variable in the parent scope. Now changing the value of $scope.model.myInt in the child scope would ALSO change the value in the parent scope. This is because the model reference in the child scope is pointed to the scope variable in the parent. We did no new assignment to the model variable in the child scope. We only changed an attribute of the model variable. Since the model variable (in the child scope) points to the model variable in the parent scope, we have successfully changed the value of myInt in the parent scope. Thus the value of $scope.model.myInt in the parent scope becomes the “single source of truth“. This is a tricky concept, thus it is considered good practice to NOT use scope inheritance. More info on prototypal inheritance in Angular can be found in the “JavaScript Prototypal Inheritance” section at the following URL: https://github.com/angular/angular.js/wiki/UnderstandingScopes. Building It: An Angular JS application using a .NET Web API Backend Now that we have a perspective on the basic components of an MVVM application built using Angular, let’s build something useful. We will build an application that can be used to send out SMS messages to a given phone number. The following diagram describes the architecture of the application we are going to build: Fig 7: Broad application architecture We are going to add an HTML Partial to our project. This partial will contain the form fields that will accept the phone number and message that needs to be sent as an SMS. It will also display all the messages that have previously been sent. All the executable code that is run on the occurrence of events (button clicks etc.) in the view resides in the controller. The controller interacts with the ASP.NET WebAPI to get a history of SMS messages, add a message etc. through a REST based API. For the purposes of simplicity, we will use an in memory data structure for the purposes of creating this application. Thus, the tasks ahead of us are: Creating the REST WebApi with GET, PUT, POST, DELETE methods. Creating the SmsView.html partial Creating the SmsController controller with methods that are called from the SmsView.html partial Add a new route that loads the controller and the partial. 1. Creating the REST WebAPI This is a simple task that should be quite straightforward to any .NET developer. The following listing shows our ApiController: public class SmsMessage { public string to { get; set; } public string message { get; set; } } public class SmsResource : SmsMessage { public int smsId { get; set; } } public class SmsResourceController : ApiController { public static Dictionary<int, SmsResource> messages = new Dictionary<int, SmsResource>(); public static int currentId = 0; // GET api/<controller> public List<SmsResource> Get() { List<SmsResource> result = new List<SmsResource>(); foreach (int key in messages.Keys) { result.Add(messages[key]); } return result; } // GET api/<controller>/5 public SmsResource Get(int id) { if (messages.ContainsKey(id)) return messages[id]; return null; } // POST api/<controller> public List<SmsResource> Post([FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { SmsResource res = (SmsResource) value; res.smsId = currentId++; messages.Add(res.smsId, res); //SentlyPlusSmsSender.SendMessage(value.to, value.message); return Get(); } } // PUT api/<controller>/5 public List<SmsResource> Put(int id, [FromBody] SmsMessage value) { //Synchronize on messages so we don't have id collisions lock (messages) { if (messages.ContainsKey(id)) { //Update the message messages[id].message = value.message; messages[id].to = value.message; } return Get(); } } // DELETE api/<controller>/5 public List<SmsResource> Delete(int id) { if (messages.ContainsKey(id)) { messages.Remove(id); } return Get(); } } Once this class is defined, we should be able to access the WebAPI by a simple GET request using the browser: http://localhost:port/api/SmsResource Notice the commented line: //SentlyPlusSmsSender.SendMessage The SentlyPlusSmsSender class is defined in the attached solution. We have shown this line as commented as we want to explain the core Angular concepts. If you load the attached solution, this line is uncommented in the source and an actual SMS will be sent! By default, the API returns XML. For consumption of the API in Angular, we would like it to return JSON. To change the default to JSON, we make the following change to WebApiConfig.cs file located in the App_Start folder. public static class WebApiConfig { public static void Register(HttpConfiguration config) { config.Routes.MapHttpRoute( name: "DefaultApi", routeTemplate: "api/{controller}/{id}", defaults: new { id = RouteParameter.Optional } ); var appXmlType = config.Formatters.XmlFormatter. SupportedMediaTypes. FirstOrDefault( t => t.MediaType == "application/xml"); config.Formatters.XmlFormatter.SupportedMediaTypes.Remove(appXmlType); } } We now have our backend REST Api which we can consume from Angular! 2. Creating the SmsView.html partial This simple partial will define two fields: the destination phone number (international format starting with a +) and the message. These fields will be bound to model.phoneNumber and model.message. We will also add a button that we shall hook up to sendMessage() in the controller. A list of all previously sent messages (bound to model.allMessages) will also be displayed below the form input. The following code shows the code for the partial:  <div class="well" style="margin-top: 30px;"> <table style="width: 100%;"> <tr> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Phone number (eg; +44 7778 609466)" ng-model="model.phoneNumber" class="form-control" style="width: 90%" onkeypress="return checkPhoneInput();" /> </td> <td style="width: 45%; text-align: center;"> <input type="text" placeholder="Message" ng-model="model.message" class="form-control" style="width: 90%" /> </td> <td style="text-align: center;"> <button class="btn btn-danger" ng-click="sendMessage();" ng-disabled="model.isAjaxInProgress" style="marginright: 5px;">Send</button> <img src="/Content/ajax-loader.gif" ng-show="model.isAjaxInProgress" /> </td> </tr> </table> </div>  <div style="margin-top: 30px;">  <div ng-show="model.allMessages.length == 0"> No messages have been sent yet! </div>  <div ng-show="model.allMessages.length == 0"> <table style="width: 100%;" class="table table-striped"> <tr> <td>Phone Number</td> <td>Message</td> <td></td> </tr>  <tr ng-repeat="message in model.allMessages"> <td>{{ message.to }}</td> <td>{{ message.message }}</td> <td> <button class="btn btn-danger" ng-click="delete(message.smsId);" ng-disabled="model.isAjaxInProgress">Delete</button> </td> </tr> </table> </div> </div> The above code is commented and should be self explanatory. Conditional rendering is achieved through using the ng-show=”condition” attribute on various div tags. Input fields are bound to the model and the send button is bound to the sendMessage() function in the controller as through the ngclick=”sendMessage()” attribute defined on the button tag. While AJAX calls are taking place, the controller sets model.isAjaxInProgress to true. Based on this variable, buttons are disabled through the ng-disabled directive which is added as an attribute to the buttons. The ng-repeat directive added as an attribute to the tr tag causes the table row to be rendered multiple times much like an ASP.NET repeater. 3. Creating the SmsController controller The penultimate piece of our application is the controller which responds to events from our view and interacts with our MVC4 REST WebAPI. The following listing shows the code we need to add to /app/js/controllers.js. Note that controller definitions can be chained. Also note that this controller “asks for” the $http service. The $http service is a simple way in Angular to do AJAX. So far we have only encountered modules, controllers, views and directives in Angular. The $http is new entity in Angular called a service. More information on Angular services can be found at the following URL: http://docs.angularjs.org/guide/dev_guide.services.understanding_services. .controller('SmsController', ['$scope', '$http', function ($scope, $http) { //We define the model $scope.model = {}; //We define the allMessages array in the model //that will contain all the messages sent so far $scope.model.allMessages = []; //The error if any $scope.model.errorMessage = undefined; //We initially load data so set the isAjaxInProgress = true; $scope.model.isAjaxInProgress = true; //Load all the messages $http({ url: '/api/smsresource', method: "GET" }). success(function (data, status, headers, config) { this callback will be called asynchronously //when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { //called asynchronously if an error occurs //or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); $scope.delete = function (id) { //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource/' + id, method: "DELETE" }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } $scope.sendMessage = function () { $scope.model.errorMessage = undefined; var message = ''; if($scope.model.message != undefined) message = $scope.model.message.trim(); if ($scope.model.phoneNumber == undefined || $scope.model.phoneNumber == '' || $scope.model.phoneNumber.length < 10 || $scope.model.phoneNumber[0] != '+') { $scope.model.errorMessage = "You must enter a valid phone number in international format. Eg: +44 7778 609466"; return; } if (message.length == 0) { $scope.model.errorMessage = "You must specify a message!"; return; } //We are making an ajax call so we set this to true $scope.model.isAjaxInProgress = true; $http({ url: '/api/smsresource', method: "POST", data: { to: $scope.model.phoneNumber, message: $scope.model.message } }). success(function (data, status, headers, config) { // this callback will be called asynchronously // when the response is available $scope.model.allMessages = data; //We are done with AJAX loading $scope.model.isAjaxInProgress = false; }). error(function (data, status, headers, config) { // called asynchronously if an error occurs // or server returns response with an error status. $scope.model.errorMessage = "Error occurred status:" + status // We are done with AJAX loading $scope.model.isAjaxInProgress = false; }); } }]); We can see from the previous listing how the functions that are called from the view are defined in the controller. It should also be evident how easy it is to make AJAX calls to consume our MVC4 REST WebAPI. Now we are left with the final piece. We need to define a route that associates a particular path with the view we have defined and the controller we have defined. 4. Add a new route that loads the controller and the partial This is the easiest part of the puzzle. We simply define another route in the /app/js/app.js file: $routeProvider.when('/sms', { templateUrl: '/app/partials/smsview.html', controller: 'SmsController' }); Conclusion In this article we have seen how much of the server side functionality in the MVC4 framework can be moved to the browser thus delivering a snappy and fast user interface. We have seen how we can build client side HTML only views that avoid the messy syntax offered by server side Razor views. We have built a functioning app from the ground up. The significant advantage of this approach to building web apps is that the front end can be completely platform independent. Even though we used ASP.NET to create our REST API, we could just easily have used any other language such as Node.js, Ruby etc without changing a single line of our front end code. Angular is a rich framework and we have only touched on basic functionality required to create a SPA. For readers who wish to delve further into the Angular framework, we would recommend the following URL as a starting point: http://docs.angularjs.org/misc/started. To get started with the code for this project: Sign up for an account at http://plus.sent.ly (free) Add your phone number Go to the “My Identies Page” Note Down your Sender ID, Consumer Key and Consumer Secret Download the code for this article at: https://docs.google.com/file/d/0BzjEWqSE31yoZjZlV0d0R2Y3eW8/edit?usp=sharing Change the values of Sender Id, Consumer Key and Consumer Secret in the web.config file Run the project through Visual Studio!

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Silverlight Recruiting Application Part 6 - Adding an Interview Scheduling Module/View

Between the last post and this one I went ahead and carried the ideas for the Jobs module and view into the Applicants module and view- they're both doing more or less the same thing, except with different objects being at their core. Made for an easy cut-and-paste operation with a few items being switched from one to another. Now that we have the ability to add postings and applicants, wouldn't it be nice if we could schedule an interview? Of course it would! Scheduling Module I think you get the drift from previous posts that these project structures start looking somewhat similar. The interview scheduling module is no different than the rest- it gets a SchedulingModule.cs file at the root that inherits from IModule, and there is a single SchedulerView.xsml and SchedulerViewModel.cs setup for our V+VM. We have one unique concern as we enter into this- RadScheduler deals with AppointmentsSource, not ItemsSource, so there are some special considerations to take into account when planning this module. First, I need something which inherits from AppointmentBase. This is the core of the RadScheduler appointment, and if you are planning to do any form of custom appointment, you'll want it to inherit from this. Then you can add-on functionality as needed. Here is my addition to the mix, the InterviewAppointment: 01.public class InterviewAppointment : AppointmentBase 02.{ 03. private int _applicantID; 04. public int ApplicantID 05. { 06. get { return this._applicantID; } 07. set 08. { 09. if (_applicantID != value) 10. { 11. _applicantID = value; 12. OnPropertyChanged("ApplicantID"); 13. } 14. } 15. } 16. 17. private int _postingID; 18. public int PostingID 19. { 20. get { return _postingID; } 21. set 22. { 23. if (_postingID != value) 24. { 25. _postingID = value; 26. OnPropertyChanged("PostingID"); 27. } 28. } 29. } 30. 31. private string _body; 32. public string Body 33. { 34. get { return _body; } 35. set 36. { 37. if (_body != value) 38. { 39. _body = value; 40. OnPropertyChanged("Body"); 41. } 42. } 43. } 44. 45. private int _interviewID; 46. public int InterviewID 47. { 48. get { return _interviewID; } 49. set 50. { 51. if (_interviewID != value) 52. { 53. _interviewID = value; 54. OnPropertyChanged("InterviewID"); 55. } 56. } 57. } 58. 59. public override IAppointment Copy() 60. { 61. IAppointment appointment = new InterviewAppointment(); 62. appointment.CopyFrom(this); 63. return appointment; 64. } 65. 66. public override void CopyFrom(IAppointment other) 67. { 68. base.CopyFrom(other); 69. var appointment = other as InterviewAppointment; 70. if (appointment != null) 71. { 72. ApplicantID = appointment.ApplicantID; 73. PostingID = appointment.PostingID; 74. Body = appointment.Body; 75. InterviewID = appointment.InterviewID; 76. } 77. } 78.} Nothing too exciting going on here, we just make sure that our custom fields are persisted (specifically set in CopyFrom at the bottom) and notifications are fired- otherwise this ends up exactly like the standard appointment as far as interactions, etc. But if we've got custom appointment items... that also means we need to customize what our appointment dialog window will look like. Customizing the Edit Appointment Dialog This initially sounds a lot more intimidating than it really is. The first step here depends on what you're dealing with for theming, but for ease of everything I went ahead and extracted my templates in Blend for RadScheduler so I could modify it as I pleased. For the faint of heart, the RadScheduler template is a few thousand lines of goodness since there are some very complex things going on in that control. I've gone ahead and trimmed down the template parts I don't need as much as possible, so what is left is all that is relevant to the Edit Appointment Dialog. Here's the resulting Xaml, with line numbers, so I can explain further: 001.<UserControl.Resources> 002.  003. <helpers:DataContextProxy x:Key="DataContextProxy" /> 004. 005. <telerik:Windows7Theme x:Key="Theme" /> 006. <SolidColorBrush x:Key="DialogWindowBackground" 007. Color="White" /> 008. <SolidColorBrush x:Key="CategorySelectorBorderBrush" 009. Color="#FFB1B1B1" /> 010. <LinearGradientBrush x:Key="RadToolBar_InnerBackground" 011. EndPoint="0.5,1" 012. StartPoint="0.5,0"> 013. <GradientStop Color="#FFFDFEFF" 014. Offset="0" /> 015. <GradientStop Color="#FFDDE9F7" 016. Offset="1" /> 017. <GradientStop Color="#FFE6F0FA" 018. Offset="0.5" /> 019. <GradientStop Color="#FFDCE6F4" 020. Offset="0.5" /> 021. </LinearGradientBrush> 022. <Style x:Key="FormElementTextBlockStyle" 023. TargetType="TextBlock"> 024. <Setter Property="HorizontalAlignment" 025. Value="Right" /> 026. <Setter Property="VerticalAlignment" 027. Value="Top" /> 028. <Setter Property="Margin" 029. Value="15, 15, 0, 2" /> 030. </Style> 031. <Style x:Key="FormElementStyle" 032. TargetType="FrameworkElement"> 033. <Setter Property="Margin" 034. Value="10, 10, 0, 2" /> 035. </Style> 036. <SolidColorBrush x:Key="GenericShallowBorderBrush" 037. Color="#FF979994" /> 038. <telerik:BooleanToVisibilityConverter x:Key="BooleanToVisibilityConverter" /> 039. <telerikScheduler:ImportanceToBooleanConverter x:Key="ImportanceToBooleanConverter" /> 040. <telerikScheduler:NullToVisibilityConverter x:Key="NullToVisibilityConverter" /> 041. <telerikScheduler:InvertedNullToVisibilityConverter x:Key="InvertedNullToVisibilityConverter" /> 042. <scheduler:ResourcesSeparatorConverter x:Key="ResourcesSeparatorConverter" /> 043. <DataTemplate x:Key="IconDataEditTemplate"> 044. <Image Source="/Telerik.Windows.Controls.Scheduler;component/Themes/Office/Images/cal.png" 045. Margin="3,3,0,0" 046. Width="16" 047. Height="16" /> 048. </DataTemplate> 049. <DataTemplate x:Key="SingleSelectionTemplate"> 050. <Grid VerticalAlignment="Stretch" 051. HorizontalAlignment="Stretch"> 052. <Grid.RowDefinitions> 053. <RowDefinition Height="Auto" /> 054. </Grid.RowDefinitions> 055. <Grid.ColumnDefinitions> 056. <ColumnDefinition Width="Auto" 057. MinWidth="84" /> 058. <ColumnDefinition Width="Auto" 059. MinWidth="200" /> 060. </Grid.ColumnDefinitions> 061. <TextBlock x:Name="SelectionNameLabel" 062. Margin="0,13,4,2" 063. Text="{Binding ResourceType.DisplayName}" 064. Style="{StaticResource FormElementTextBlockStyle}" 065. Grid.Column="0" /> 066. <telerikInput:RadComboBox ItemsSource="{Binding ResourceItems}" 067. Width="185" 068. Margin="5,10,20,2" 069. HorizontalAlignment="Left" 070. Grid.Column="1" 071. ClearSelectionButtonVisibility="Visible" 072. ClearSelectionButtonContent="Clear All" 073. DisplayMemberPath="Resource.DisplayName" 074. telerik:StyleManager.Theme="{StaticResource Theme}" 075. SelectedItem="{Binding SelectedItem, Mode=TwoWay}" /> 076. </Grid> 077. </DataTemplate> 078. <DataTemplate x:Key="MultipleSelectionTemplate"> 079. <Grid VerticalAlignment="Stretch" 080. HorizontalAlignment="Stretch"> 081. <Grid.RowDefinitions> 082. <RowDefinition Height="Auto" /> 083. </Grid.RowDefinitions> 084. <Grid.ColumnDefinitions> 085. <ColumnDefinition Width="Auto" 086. MinWidth="84" /> 087. <ColumnDefinition Width="Auto" 088. MinWidth="200" /> 089. </Grid.ColumnDefinitions> 090. <TextBlock x:Name="SelectionNameLabel" 091. Grid.Column="0" 092. Text="{Binding ResourceType.DisplayName}" 093. Margin="0,13,4,2" 094. Style="{StaticResource FormElementTextBlockStyle}" /> 095. <telerikInput:RadComboBox Grid.Column="1" 096. Width="185" 097. HorizontalAlignment="Left" 098. Margin="5,10,20,2" 099. ItemsSource="{Binding ResourceItems}" 100. SelectedIndex="{Binding SelectedIndex, Mode=TwoWay}" 101. ClearSelectionButtonVisibility="Visible" 102. ClearSelectionButtonContent="Clear All" 103. telerik:StyleManager.Theme="{StaticResource Theme}"> 104. <telerikInput:RadComboBox.ItemTemplate> 105. <DataTemplate> 106. <Grid HorizontalAlignment="Stretch" 107. VerticalAlignment="Stretch"> 108. <CheckBox VerticalAlignment="Center" 109. HorizontalContentAlignment="Stretch" 110. VerticalContentAlignment="Center" 111. IsChecked="{Binding IsChecked, Mode=TwoWay}" 112. Content="{Binding Resource.DisplayName}"> 113. <CheckBox.ContentTemplate> 114. <DataTemplate> 115. <TextBlock HorizontalAlignment="Stretch" 116. VerticalAlignment="Stretch" 117. Text="{Binding Content, RelativeSource={RelativeSource TemplatedParent}}" /> 118. </DataTemplate> 119. </CheckBox.ContentTemplate> 120. </CheckBox> 121. </Grid> 122. </DataTemplate> 123. </telerikInput:RadComboBox.ItemTemplate> 124. </telerikInput:RadComboBox> 125. </Grid> 126. </DataTemplate> 127. <scheduler:ResourceTypeTemplateSelector x:Key="ItemTemplateSelector" 128. MultipleSelectionTemplate="{StaticResource MultipleSelectionTemplate}" 129. SingleSelectionTemplate="{StaticResource SingleSelectionTemplate}" /> 130.  131. 132. <ControlTemplate x:Key="EditAppointmentTemplate" 133. TargetType="telerikScheduler:AppointmentDialogWindow"> 134. <StackPanel Background="{TemplateBinding Background}" 135. UseLayoutRounding="True"> 136. <StackPanel Grid.Row="0" 137. Orientation="Horizontal" 138. Background="{StaticResource RadToolBar_InnerBackground}" 139. Grid.ColumnSpan="2" 140. Height="0"> 141.  142. <Border Margin="1,1,0,0" 143. Background="#50000000" 144. HorizontalAlignment="Left" 145. VerticalAlignment="Center" 146. Width="2" 147. Height="16"> 148. <Border Margin="0,0,1,1" 149. Background="#80FFFFFF" 150. HorizontalAlignment="Left" 151. Width="1" /> 152. </Border> 153. <Border Margin="1,1,0,0" 154. Background="#50000000" 155. HorizontalAlignment="Left" 156. VerticalAlignment="Center" 157. Width="2" 158. Height="16"> 159. <Border Margin="0,0,1,1" 160. Background="#80FFFFFF" 161. HorizontalAlignment="Left" 162. Width="1" /> 163. </Border> 164. <TextBlock telerik:LocalizationManager.ResourceKey="ShowAs" 165. VerticalAlignment="Center" 166. Margin="5,0,0,0" /> 167. <telerikInput:RadComboBox ItemsSource="{TemplateBinding TimeMarkers}" 168. Width="100" 169. Height="20" 170. VerticalAlignment="Center" 171. Margin="5,0,0,0" 172. ClearSelectionButtonVisibility="Visible" 173. ClearSelectionButtonContent="Clear" 174. SelectedItem="{Binding TimeMarker,RelativeSource={RelativeSource TemplatedParent},Mode=TwoWay}" 175. telerik:StyleManager.Theme="{StaticResource Theme}"> 176. <telerikInput:RadComboBox.ItemTemplate> 177. <DataTemplate> 178. <StackPanel Orientation="Horizontal"> 179. <Rectangle Fill="{Binding TimeMarkerBrush}" 180. Margin="2" 181. Width="12" 182. Height="12" /> 183. <TextBlock Text="{Binding TimeMarkerName}" 184. Margin="2" /> 185. </StackPanel> 186. </DataTemplate> 187. </telerikInput:RadComboBox.ItemTemplate> 188. </telerikInput:RadComboBox> 189. <telerik:RadToggleButton x:Name="High" 190. BorderThickness="0" 191. Background="{StaticResource RadToolBar_InnerBackground}" 192. DataContext="{TemplateBinding EditedAppointment}" 193. telerik:StyleManager.Theme="{StaticResource Theme}" 194. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=High}" 195. Margin="2,2,0,2" 196. Width="23" 197. Height="23" 198. HorizontalContentAlignment="Center" 199. ToolTipService.ToolTip="High importance" 200. CommandParameter="High" 201. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 202. <StackPanel HorizontalAlignment="Center"> 203. <Path Stretch="Fill" 204. Height="10" 205. HorizontalAlignment="Center" 206. VerticalAlignment="Top" 207. Width="5.451" 208. Data="M200.39647,58.840393 C200.39337,58.336426 201.14566,57.683922 202.56244,57.684292 C204.06589,57.684685 204.73764,58.357765 204.72783,58.992363 C205.04649,61.795574 203.04713,64.181099 202.47388,66.133446 C201.93753,64.154961 199.9471,61.560352 200.39647,58.840393 z"> 209. <Path.Fill> 210. <LinearGradientBrush EndPoint="1.059,0.375" 211. StartPoint="-0.457,0.519"> 212. <GradientStop Color="#FFFF0606" 213. Offset="0.609" /> 214. <GradientStop Color="#FFBF0303" 215. Offset="0.927" /> 216. </LinearGradientBrush> 217. </Path.Fill> 218. </Path> 219. <Ellipse Height="3" 220. HorizontalAlignment="Center" 221. Margin="0,-1,0,0" 222. VerticalAlignment="Top" 223. Width="3"> 224. <Ellipse.Fill> 225. <RadialGradientBrush> 226. <GradientStop Color="#FFFF0606" 227. Offset="0" /> 228. <GradientStop Color="#FFBF0303" 229. Offset="1" /> 230. </RadialGradientBrush> 231. </Ellipse.Fill> 232. </Ellipse> 233. </StackPanel> 234. </telerik:RadToggleButton> 235. <telerik:RadToggleButton x:Name="Low" 236. HorizontalContentAlignment="Center" 237. BorderThickness="0" 238. Background="{StaticResource RadToolBar_InnerBackground}" 239. DataContext="{TemplateBinding EditedAppointment}" 240. IsChecked="{Binding Importance,Mode=TwoWay, Converter={StaticResource ImportanceToBooleanConverter},ConverterParameter=Low}" 241. Margin="0,2,0,2" 242. Width="23" 243. Height="23" 244. ToolTipService.ToolTip="Low importance" 245. CommandParameter="Low" 246. telerik:StyleManager.Theme="{StaticResource Theme}" 247. Command="telerikScheduler:RadSchedulerCommands.SetAppointmentImportance"> 248. <Path Stretch="Fill" 249. Height="12" 250. HorizontalAlignment="Center" 251. VerticalAlignment="Top" 252. Width="9" 253. Data="M222.40353,60.139881 L226.65768,60.139843 L226.63687,67.240196 L229.15347,67.240196 L224.37816,71.394943 L219.65274,67.240196 L222.37572,67.219345 z" 254. Stroke="#FF0365A7"> 255. <Path.Fill> 256. <LinearGradientBrush EndPoint="1.059,0.375" 257. StartPoint="-0.457,0.519"> 258. <GradientStop Color="#FFBBE4FF" /> 259. <GradientStop Color="#FF024572" 260. Offset="0.836" /> 261. <GradientStop Color="#FF43ADF4" 262. Offset="0.466" /> 263. </LinearGradientBrush> 264. </Path.Fill> 265. </Path> 266. </telerik:RadToggleButton> 267. </StackPanel > 268. <Border DataContext="{TemplateBinding EditedAppointment}" 269. Background="{Binding Category.CategoryBrush}" 270. Visibility="{Binding Category,Converter={StaticResource NullToVisibilityConverter}}" 271. CornerRadius="3" 272. Height="20" 273. Margin="5,10,5,0"> 274. <TextBlock Text="{Binding Category.DisplayName}" 275. VerticalAlignment="Center" 276. Margin="5,0,0,0" /> 277. </Border> 278. <Grid VerticalAlignment="Stretch" 279. HorizontalAlignment="Stretch" 280. DataContext="{TemplateBinding EditedAppointment}" 281. Background="{TemplateBinding Background}"> 282. <Grid.RowDefinitions> 283. <RowDefinition Height="Auto" /> 284. <RowDefinition Height="Auto" /> 285. <RowDefinition Height="Auto" /> 286. <RowDefinition Height="Auto" /> 287. <RowDefinition Height="Auto" /> 288. <RowDefinition Height="Auto" /> 289. <RowDefinition Height="Auto" /> 290. <RowDefinition Height="Auto" /> 291. <RowDefinition Height="Auto" /> 292. <RowDefinition Height="Auto" /> 293. </Grid.RowDefinitions> 294. <Grid.ColumnDefinitions> 295. <ColumnDefinition Width="Auto" 296. MinWidth="100" /> 297. <ColumnDefinition Width="Auto" 298. MinWidth="200" /> 299. </Grid.ColumnDefinitions> 300.  301. <TextBlock x:Name="SubjectLabel" 302. Grid.Row="0" 303. Grid.Column="0" 304. Margin="0,15,0,2" 305. telerik:LocalizationManager.ResourceKey="Subject" 306. Style="{StaticResource FormElementTextBlockStyle}" /> 307. <TextBox x:Name="Subject" 308. Grid.Row="0" 309. Grid.Column="1" 310. MinHeight="22" 311. Padding="4 2" 312. Width="340" 313. HorizontalAlignment="Left" 314. Text="{Binding Subject, Mode=TwoWay}" 315. MaxLength="255" 316. telerik:StyleManager.Theme="{StaticResource Theme}" 317. Margin="10,12,20,2" /> 318.  319. <TextBlock x:Name="DescriptionLabel" 320. Grid.Row="1" 321. Grid.Column="0" 322. Margin="0,13,0,2" 323. telerik:LocalizationManager.ResourceKey="Body" 324. Style="{StaticResource FormElementTextBlockStyle}" /> 325. <TextBox x:Name="Body" 326. VerticalAlignment="top" 327. Grid.Row="1" 328. Grid.Column="1" 329. Height="Auto" 330. MaxHeight="82" 331. Width="340" 332. HorizontalAlignment="Left" 333. MinHeight="22" 334. Padding="4 2" 335. TextWrapping="Wrap" 336. telerik:StyleManager.Theme="{StaticResource Theme}" 337. Text="{Binding Body, Mode=TwoWay}" 338. AcceptsReturn="true" 339. Margin="10,10,20,2" 340. HorizontalScrollBarVisibility="Auto" 341. VerticalScrollBarVisibility="Auto" /> 342.  343. <TextBlock x:Name="StartDateLabel" 344. Grid.Row="2" 345. Grid.Column="0" 346. Margin="0,13,0,2" 347. telerik:LocalizationManager.ResourceKey="StartTime" 348. Style="{StaticResource FormElementTextBlockStyle}" /> 349. <telerikScheduler:DateTimePicker x:Name="StartDateTime" 350. Height="22" 351. Grid.Row="2" 352. Grid.Column="1" 353. HorizontalAlignment="Left" 354. Margin="10,10,20,2" 355. Style="{StaticResource FormElementStyle}" 356. SelectedDateTime="{Binding Start, Mode=TwoWay}" 357. telerikScheduler:StartEndDatePicker.EndPicker="{Binding ElementName=EndDateTime}" 358. IsTabStop="False" 359. IsEnabled="False" /> 360. <TextBlock x:Name="EndDateLabel" 361. Grid.Row="3" 362. Grid.Column="0" 363. Margin="0,13,0,2" 364. telerik:LocalizationManager.ResourceKey="EndTime" 365. Style="{StaticResource FormElementTextBlockStyle}" /> 366. <telerikScheduler:DateTimePicker x:Name="EndDateTime" 367. Height="22" 368. Grid.Row="3" 369. Grid.Column="1" 370. HorizontalAlignment="Left" 371. Margin="10,10,20,2" 372. Style="{StaticResource FormElementStyle}" 373. IsTabStop="False" 374. IsEnabled="False" 375. SelectedDateTime="{Binding End, Mode=TwoWay}" /> 376.  377. <CheckBox x:Name="AllDayEventCheckbox" 378. IsChecked="{Binding IsAllDayEvent, Mode=TwoWay}" 379. Grid.Row="4" 380. Grid.Column="1" 381. Margin="10,10,20,2" 382. HorizontalAlignment="Left" 383. telerik:StyleManager.Theme="{StaticResource Theme}" 384. telerik:LocalizationManager.ResourceKey="AllDayEvent"> 385. <telerik:CommandManager.InputBindings> 386. <telerik:InputBindingCollection> 387. <telerik:MouseBinding Command="telerikScheduler:RadSchedulerCommands.ChangeTimePickersVisibility" 388. Gesture="LeftClick" /> 389. </telerik:InputBindingCollection> 390. </telerik:CommandManager.InputBindings> 391. </CheckBox> 392. <Grid Grid.Row="5" 393. Grid.ColumnSpan="2"> 394. <Grid.ColumnDefinitions> 395. <ColumnDefinition Width="Auto" 396. MinWidth="100" /> 397. <ColumnDefinition Width="Auto" 398. MinWidth="200" /> 399. </Grid.ColumnDefinitions> 400. <Grid.RowDefinitions> 401. <RowDefinition Height="Auto" /> 402. <RowDefinition Height="Auto" /> 403. </Grid.RowDefinitions> 404. <TextBlock Text="Applicant" 405. Margin="0,13,0,2" 406. Style="{StaticResource FormElementTextBlockStyle}" /> 407. <telerikInput:RadComboBox IsEditable="False" 408. Grid.Column="1" 409. Height="24" 410. VerticalAlignment="Center" 411. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.ApplicantList}" 412. SelectedValue="{Binding ApplicantID, Mode=TwoWay}" 413. SelectedValuePath="ApplicantID" 414. DisplayMemberPath="FirstName" /> 415. 416. <TextBlock Text="Job" 417. Margin="0,13,0,2" 418. Grid.Row="1" 419. Style="{StaticResource FormElementTextBlockStyle}" /> 420. <telerikInput:RadComboBox IsEditable="False" 421. Grid.Column="1" 422. Grid.Row="1" 423. Height="24" 424. VerticalAlignment="Center" 425. ItemsSource="{Binding Source={StaticResource DataContextProxy}, Path=DataSource.JobsList}" 426. SelectedValue="{Binding PostingID, Mode=TwoWay}" 427. SelectedValuePath="PostingID" 428. DisplayMemberPath="JobTitle"/> 429. </Grid> 430.  431. <Grid x:Name="ResourcesLayout" 432. Grid.Row="7" 433. Grid.Column="0" 434. Grid.ColumnSpan="2" 435. MaxHeight="130" 436. Margin="20,5,20,0"> 437. <Border Margin="0" 438. BorderThickness="1" 439. BorderBrush="{StaticResource GenericShallowBorderBrush}" 440. Visibility="{Binding ElementName=ResourcesScrollViewer, Path=ComputedVerticalScrollBarVisibility}"></Border> 441. <ScrollViewer x:Name="ResourcesScrollViewer" 442. IsTabStop="false" 443. Grid.Row="6" 444. Grid.Column="0" 445. Grid.ColumnSpan="2" 446. Margin="1" 447. telerik:StyleManager.Theme="{StaticResource Theme}" 448. VerticalScrollBarVisibility="Auto"> 449. <scheduler:ResourcesItemsControl x:Name="PART_Resources" 450. HorizontalAlignment="Left" 451. Padding="0,2,0,5" 452. IsTabStop="false" 453. ItemsSource="{TemplateBinding ResourceTypeModels}" 454. ItemTemplateSelector="{StaticResource ItemTemplateSelector}" /> 455. </ScrollViewer> 456. </Grid> 457. <StackPanel x:Name="FooterControls" 458. Margin="5 10 10 10" 459. Grid.Row="8" 460. Grid.Column="1" 461. HorizontalAlignment="Left" 462. Orientation="Horizontal"> 463. <telerik:RadButton x:Name="OKButton" 464. Margin="5" 465. Padding="10 0" 466. MinWidth="80" 467. Command="telerikScheduler:RadSchedulerCommands.SaveAppointment" 468. telerik:StyleManager.Theme="{StaticResource Theme}" 469. telerikNavigation:RadWindow.ResponseButton="Accept" 470. telerik:LocalizationManager.ResourceKey="SaveAndCloseCommandText"> 471. </telerik:RadButton> 472. <telerik:RadButton x:Name="CancelButton" 473. Margin="5" 474. Padding="10 0" 475. MinWidth="80" 476. telerik:LocalizationManager.ResourceKey="Cancel" 477. telerik:StyleManager.Theme="{StaticResource Theme}" 478. telerikNavigation:RadWindow.ResponseButton="Cancel" 479. Command="telerik:WindowCommands.Close"> 480. </telerik:RadButton> 481. </StackPanel> 482. </Grid> 483. <vsm:VisualStateManager.VisualStateGroups> 484. <vsm:VisualStateGroup x:Name="RecurrenceRuleState"> 485. <vsm:VisualState x:Name="RecurrenceRuleIsNull"> 486. <Storyboard> 487. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 488. Storyboard.TargetProperty="IsEnabled" 489. Duration="0"> 490. <DiscreteObjectKeyFrame KeyTime="0" 491. Value="True" /> 492. </ObjectAnimationUsingKeyFrames> 493. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 494. Storyboard.TargetProperty="IsEnabled" 495. Duration="0"> 496. <DiscreteObjectKeyFrame KeyTime="0" 497. Value="True" /> 498. </ObjectAnimationUsingKeyFrames> 499. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 500. Storyboard.TargetProperty="IsEnabled" 501. Duration="0"> 502. <DiscreteObjectKeyFrame KeyTime="0" 503. Value="True" /> 504. </ObjectAnimationUsingKeyFrames> 505. </Storyboard> 506. </vsm:VisualState> 507. <vsm:VisualState x:Name="RecurrenceRuleIsNotNull"> 508. <Storyboard> 509. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="StartDateTime" 510. Storyboard.TargetProperty="IsEnabled" 511. Duration="0"> 512. <DiscreteObjectKeyFrame KeyTime="0" 513. Value="False" /> 514. </ObjectAnimationUsingKeyFrames> 515. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="EndDateTime" 516. Storyboard.TargetProperty="IsEnabled" 517. Duration="0"> 518. <DiscreteObjectKeyFrame KeyTime="0" 519. Value="False" /> 520. </ObjectAnimationUsingKeyFrames> 521. <ObjectAnimationUsingKeyFrames Storyboard.TargetName="AllDayEventCheckbox" 522. Storyboard.TargetProperty="IsEnabled" 523. Duration="0"> 524. <DiscreteObjectKeyFrame KeyTime="0" 525. Value="False" /> 526. </ObjectAnimationUsingKeyFrames> 527. </Storyboard> 528. </vsm:VisualState> 529. </vsm:VisualStateGroup> 530. </vsm:VisualStateManager.VisualStateGroups> 531. </StackPanel> 532. </ControlTemplate> 533. <DataTemplate x:Key="AppointmentDialogWindowHeaderDataTemplate"> 534. <StackPanel Orientation="Horizontal" 535. MaxWidth="400"> 536. <TextBlock telerik:LocalizationManager.ResourceKey="Event" 537. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource BooleanToVisibilityConverter}}" /> 538. <TextBlock telerik:LocalizationManager.ResourceKey="Appointment" 539. Visibility="{Binding Appointment.IsAllDayEvent, Converter={StaticResource InvertedBooleanToVisibilityConverter}}" /> 540. <TextBlock Text=" - " /> 541. <TextBlock x:Name="SubjectTextBlock" 542. Visibility="{Binding Appointment.Subject, Converter={StaticResource NullToVisibilityConverter}}" 543. Text="{Binding Appointment.Subject}" /> 544. <TextBlock telerik:LocalizationManager.ResourceKey="Untitled" 545. Visibility="{Binding Appointment.Subject, Converter={StaticResource InvertedNullToVisibilityConverter}}" /> 546. </StackPanel> 547. </DataTemplate> 548. <Style x:Key="EditAppointmentStyle" 549. TargetType="telerikScheduler:AppointmentDialogWindow"> 550. <Setter Property="IconTemplate" 551. Value="{StaticResource IconDataEditTemplate}" /> 552. <Setter Property="HeaderTemplate" 553. Value="{StaticResource AppointmentDialogWindowHeaderDataTemplate}" /> 554. <Setter Property="Background" 555. Value="{StaticResource DialogWindowBackground}" /> 556. <Setter Property="Template" 557. Value="{StaticResource EditAppointmentTemplate}" /> 558. </Style> 559.</UserControl.Resources> The first line there is the DataContextProxy I mentioned previously- we use that again to work a bit of magic in this template. Where we start getting into the dialog in question is line 132, but line 407 is where things start getting interesting. The ItemsSource is pointing at a list that exists in my ViewModel (or code-behind, if it is used as a DataContext), the SelectedValue is the item I am actually binding from the applicant (note the TwoWay binding), and SelectedValuePath and DisplayMemberPath ensure the proper applicant is being displayed from the collection. You will also see similar starting on line 420 where I do the same for the Jobs we'll be displaying. Just to wrap-up the Xaml, here's the RadScheduler declaraction that ties this all together and will be the main focus of our view: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. AppointmentsSource="{Binding Interviews}" 09. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 10. command:AppointmentAddedEventClass.Command="{Binding AddAppointmentCommand}" 11. command:ApptCreatedEventClass.Command="{Binding ApptCreatingCommand}" 12. command:ApptEditedEventClass.Command="{Binding ApptEditedCommand}" 13. command:ApptDeletedEventClass.Command="{Binding ApptDeletedCommand}"> 14.</telerikScheduler:RadScheduler> Now, we get to the ViewModel and what it takes to get that rigged up. And for those of you who remember the jobs post, those command:s in the Xaml are pointing to attached behavior commands that reproduce the respective events. This becomes very handy when we're setting up the code-behind version. ;) ViewModel I've been liking this approach so far, so I'm going to put the entire ViewModel here and then go into the lines of interest. Of course, feel free to ask me questions about anything that isn't clear (by line number, ideally) so I can help out if I have missed anything important: 001.public class SchedulerViewModel : ViewModelBase 002.{ 003. private readonly IEventAggregator eventAggregator; 004. private readonly IRegionManager regionManager; 005. 006. public RecruitingContext context; 007. 008. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 009. public ObservableItemCollection<InterviewAppointment> Interviews 010. { 011. get { return _interviews; } 012. set 013. { 014. if (_interviews != value) 015. { 016. _interviews = value; 017. NotifyChanged("Interviews"); 018. } 019. } 020. } 021. 022. private QueryableCollectionView _jobsList; 023. public QueryableCollectionView JobsList 024. { 025. get { return this._jobsList; } 026. set 027. { 028. if (this._jobsList != value) 029. { 030. this._jobsList = value; 031. this.NotifyChanged("JobsList"); 032. } 033. } 034. } 035. 036. private QueryableCollectionView _applicantList; 037. public QueryableCollectionView ApplicantList 038. { 039. get { return _applicantList; } 040. set 041. { 042. if (_applicantList != value) 043. { 044. _applicantList = value; 045. NotifyChanged("ApplicantList"); 046. } 047. } 048. } 049. 050. public DelegateCommand<object> AddAppointmentCommand { get; set; } 051. public DelegateCommand<object> ApptCreatingCommand { get; set; } 052. public DelegateCommand<object> ApptEditedCommand { get; set; } 053. public DelegateCommand<object> ApptDeletedCommand { get; set; } 054. 055. public SchedulerViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 056. { 057. // set Unity items 058. this.eventAggregator = eventAgg; 059. this.regionManager = regionmanager; 060. 061. // load our context 062. context = new RecruitingContext(); 063. LoadOperation<Interview> loadOp = context.Load(context.GetInterviewsQuery()); 064. loadOp.Completed += new EventHandler(loadOp_Completed); 065. 066. this._jobsList = new QueryableCollectionView(context.JobPostings); 067. context.Load(context.GetJobPostingsQuery()); 068. 069. this._applicantList = new QueryableCollectionView(context.Applicants); 070. context.Load(context.GetApplicantsQuery()); 071. 072. AddAppointmentCommand = new DelegateCommand<object>(this.AddAppt); 073. ApptCreatingCommand = new DelegateCommand<object>(this.ApptCreating); 074. ApptEditedCommand = new DelegateCommand<object>(this.ApptEdited); 075. ApptDeletedCommand = new DelegateCommand<object>(this.ApptDeleted); 076. 077. } 078. 079. void loadOp_Completed(object sender, EventArgs e) 080. { 081. LoadOperation loadop = sender as LoadOperation; 082. 083. foreach (var ent in loadop.Entities) 084. { 085. _interviews.Add(EntityToAppointment(ent as Interview)); 086. } 087. } 088. 089. #region Appointment Adding 090. 091. public void AddAppt(object obj) 092. { 093. // now we have a new InterviewAppointment to add to our QCV :) 094. InterviewAppointment newInterview = obj as InterviewAppointment; 095. 096. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 097. this.context.SubmitChanges((s) => 098. { 099. ActionHistory myAction = new ActionHistory(); 100. myAction.InterviewID = newInterview.InterviewID; 101. myAction.PostingID = newInterview.PostingID; 102. myAction.ApplicantID = newInterview.ApplicantID; 103. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 104. myAction.TimeStamp = DateTime.Now; 105. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 106. } 107. , null); 108. } 109. 110. public void ApptCreating(object obj) 111. { 112. // handled in the behavior, just a placeholder to ensure it runs :) 113. } 114. 115. #endregion 116. 117. #region Appointment Editing 118. 119. public void ApptEdited(object obj) 120. { 121. Interview editedInterview = (from x in context.Interviews 122. where x.InterviewID == (obj as InterviewAppointment).InterviewID 123. select x).SingleOrDefault(); 124. 125. CopyAppointmentEdit(editedInterview, obj as InterviewAppointment); 126. 127. context.SubmitChanges((s) => { 128. ActionHistory myAction = new ActionHistory(); 129. myAction.InterviewID = editedInterview.InterviewID; 130. myAction.PostingID = editedInterview.PostingID; 131. myAction.ApplicantID = editedInterview.ApplicantID; 132. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 133. myAction.TimeStamp = DateTime.Now; 134. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); } 135. , null); 136. } 137. 138. #endregion 139. 140. #region Appointment Deleting 141. 142. public void ApptDeleted(object obj) 143. { 144. Interview deletedInterview = (from x in context.Interviews 145. where x.InterviewID == (obj as InterviewAppointment).InterviewID 146. select x).SingleOrDefault(); 147. 148. context.Interviews.Remove(deletedInterview); 149. context.SubmitChanges((s) => 150. { 151. ActionHistory myAction = new ActionHistory(); 152. myAction.InterviewID = deletedInterview.InterviewID; 153. myAction.PostingID = deletedInterview.PostingID; 154. myAction.ApplicantID = deletedInterview.ApplicantID; 155. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 156. myAction.TimeStamp = DateTime.Now; 157. eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 158. } 159. , null); 160. } 161. 162. #endregion 163. 164. #region Appointment Helpers :) 165. 166. public Interview AppointmentToEntity(InterviewAppointment ia) 167. { 168. Interview newInterview = new Interview(); 169. newInterview.Subject = ia.Subject; 170. newInterview.Body = ia.Body; 171. newInterview.Start = ia.Start; 172. newInterview.End = ia.End; 173. newInterview.ApplicantID = ia.ApplicantID; 174. newInterview.PostingID = ia.PostingID; 175. newInterview.InterviewID = ia.InterviewID; 176. 177. return newInterview; 178. } 179. 180. public InterviewAppointment EntityToAppointment(Interview ia) 181. { 182. InterviewAppointment newInterview = new InterviewAppointment(); 183. newInterview.Subject = ia.Subject; 184. newInterview.Body = ia.Body; 185. newInterview.Start = ia.Start; 186. newInterview.End = ia.End; 187. newInterview.ApplicantID = ia.ApplicantID; 188. newInterview.PostingID = ia.PostingID; 189. newInterview.InterviewID = ia.InterviewID; 190. 191. return newInterview; 192. } 193. 194. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 195. { 196. entityInterview.Subject = appointmentInterview.Subject; 197. entityInterview.Body = appointmentInterview.Body; 198. entityInterview.Start = appointmentInterview.Start; 199. entityInterview.End = appointmentInterview.End; 200. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 201. entityInterview.PostingID = appointmentInterview.PostingID; 202. } 203. 204. #endregion 205.} One thing we're doing here which you won't see in any of the other ViewModels is creating a duplicate collection. I know this is something which will be fixed down the line for using RadScheduler, simplifying this process, but with WCF RIA changing as it does I wanted to ensure functionality would remain consistent as I continued development on this application. So, I do a little bit of duplication, but for the greater good. This all takes place starting on line 79, so for every entity that comes back we add it to the collection that is bound to RadScheduler. Otherwise, the DelegateCommands that you see correspond directly to the events they are named after. In each case, rather than sending over the full event arguments, I just send in the appointment in question (coming through as the object obj in all cases) so I can add (line 91), edit (line 119), and delete appointments (line 142) like normal. This just ensures they get updated back to my database. Also, the one bit of code you won't see is for the Appointment Creating (line 110) event- that is because in the command I've created I simply make the replacement I need to: 1.void element_AppointmentCreating(object sender, AppointmentCreatingEventArgs e) 2.{ 3. e.NewAppointment = new InterviewAppointment(); 4. base.ExecuteCommand(); 5.} And the ViewModel is none the wiser, the appointments just work as far as it is concerned since as they are created they become InterviewAppointments. End result? I've customized my EditAppointmentDialog as follows: And adding, editing, and deleting appointments works like a charm. I can even 'edit' by moving appointments around RadScheduler, so as they are dropped into a timeslot they perform their full edit routine and things get updated. And then, the Code-Behind Version Perhaps the thing I like the most about doing one then the other is I get to steal 90% or more of the code from the MVVM version. For example, the only real changes to the Code-Behind Xaml file exist in the control declaration, in which I use events instead of attached-behavior-event-commands: 01.<telerikScheduler:RadScheduler x:Name="xJobsScheduler" 02. Grid.Row="1" 03. Grid.Column="1" 04. Width="800" 05. MinWidth="600" 06. Height="500" 07. MinHeight="300" 08. EditAppointmentStyle="{StaticResource EditAppointmentStyle}" 09. AppointmentAdded="xJobsScheduler_AppointmentAdded" 10. AppointmentCreating="xJobsScheduler_AppointmentCreating" 11. AppointmentEdited="xJobsScheduler_AppointmentEdited" 12. AppointmentDeleted="xJobsScheduler_AppointmentDeleted"> 13.</telerikScheduler:RadScheduler> Easy, right? Otherwise, all the same styling in UserControl.Resources was re-used, right down to the DataContextProxy that lets us bind to a collection from our viewmodel (in this case, our code-behind) to use within the DataTemplate. The code conversion gets even easier, as I could literally copy and paste almost everything from the ViewModel to my Code-Behind, just a matter of pasting the right section into the right event. Here's the code-behind as proof: 001.public partial class SchedulingView : UserControl, INotifyPropertyChanged 002.{ 003. public RecruitingContext context; 004. 005. private QueryableCollectionView _jobsList; 006. public QueryableCollectionView JobsList 007. { 008. get { return this._jobsList; } 009. set 010. { 011. if (this._jobsList != value) 012. { 013. this._jobsList = value; 014. this.NotifyChanged("JobsList"); 015. } 016. } 017. } 018. 019. private QueryableCollectionView _applicantList; 020. public QueryableCollectionView ApplicantList 021. { 022. get { return _applicantList; } 023. set 024. { 025. if (_applicantList != value) 026. { 027. _applicantList = value; 028. NotifyChanged("ApplicantList"); 029. } 030. } 031. } 032. 033. private ObservableItemCollection<InterviewAppointment> _interviews = new ObservableItemCollection<InterviewAppointment>(); 034. public ObservableItemCollection<InterviewAppointment> Interviews 035. { 036. get { return _interviews; } 037. set 038. { 039. if (_interviews != value) 040. { 041. _interviews = value; 042. NotifyChanged("Interviews"); 043. } 044. } 045. } 046. 047. public SchedulingView() 048. { 049. InitializeComponent(); 050. 051. this.DataContext = this; 052. 053. this.Loaded += new RoutedEventHandler(SchedulingView_Loaded); 054. } 055. 056. void SchedulingView_Loaded(object sender, RoutedEventArgs e) 057. { 058. this.xJobsScheduler.AppointmentsSource = Interviews; 059. 060. context = new RecruitingContext(); 061. 062. LoadOperation loadop = context.Load(context.GetInterviewsQuery()); 063. loadop.Completed += new EventHandler(loadop_Completed); 064. 065. this._applicantList = new QueryableCollectionView(context.Applicants); 066. context.Load(context.GetApplicantsQuery()); 067. 068. this._jobsList = new QueryableCollectionView(context.JobPostings); 069. context.Load(context.GetJobPostingsQuery()); 070. } 071. 072. void loadop_Completed(object sender, EventArgs e) 073. { 074. LoadOperation loadop = sender as LoadOperation; 075. 076. _interviews.Clear(); 077. 078. foreach (var ent in loadop.Entities) 079. { 080. _interviews.Add(EntityToAppointment(ent as Interview)); 081. } 082. } 083. 084. private void xJobsScheduler_AppointmentAdded(object sender, Telerik.Windows.Controls.AppointmentAddedEventArgs e) 085. { 086. // now we have a new InterviewAppointment to add to our QCV :) 087. InterviewAppointment newInterview = e.Appointment as InterviewAppointment; 088. 089. this.context.Interviews.Add(AppointmentToEntity(newInterview)); 090. this.context.SubmitChanges((s) => 091. { 092. ActionHistory myAction = new ActionHistory(); 093. myAction.InterviewID = newInterview.InterviewID; 094. myAction.PostingID = newInterview.PostingID; 095. myAction.ApplicantID = newInterview.ApplicantID; 096. myAction.Description = String.Format("Interview with {0} has been created by {1}", newInterview.ApplicantID.ToString(), "default user"); 097. myAction.TimeStamp = DateTime.Now; 098. context.ActionHistories.Add(myAction); 099. context.SubmitChanges(); 100. } 101. , null); 102. } 103. 104. private void xJobsScheduler_AppointmentCreating(object sender, Telerik.Windows.Controls.AppointmentCreatingEventArgs e) 105. { 106. e.NewAppointment = new InterviewAppointment(); 107. } 108. 109. private void xJobsScheduler_AppointmentEdited(object sender, Telerik.Windows.Controls.AppointmentEditedEventArgs e) 110. { 111. Interview editedInterview = (from x in context.Interviews 112. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 113. select x).SingleOrDefault(); 114. 115. CopyAppointmentEdit(editedInterview, e.Appointment as InterviewAppointment); 116. 117. context.SubmitChanges((s) => 118. { 119. ActionHistory myAction = new ActionHistory(); 120. myAction.InterviewID = editedInterview.InterviewID; 121. myAction.PostingID = editedInterview.PostingID; 122. myAction.ApplicantID = editedInterview.ApplicantID; 123. myAction.Description = String.Format("Interview with {0} has been modified by {1}", editedInterview.ApplicantID.ToString(), "default user"); 124. myAction.TimeStamp = DateTime.Now; 125. context.ActionHistories.Add(myAction); 126. context.SubmitChanges(); 127. } 128. , null); 129. } 130. 131. private void xJobsScheduler_AppointmentDeleted(object sender, Telerik.Windows.Controls.AppointmentDeletedEventArgs e) 132. { 133. Interview deletedInterview = (from x in context.Interviews 134. where x.InterviewID == (e.Appointment as InterviewAppointment).InterviewID 135. select x).SingleOrDefault(); 136. 137. context.Interviews.Remove(deletedInterview); 138. context.SubmitChanges((s) => 139. { 140. ActionHistory myAction = new ActionHistory(); 141. myAction.InterviewID = deletedInterview.InterviewID; 142. myAction.PostingID = deletedInterview.PostingID; 143. myAction.ApplicantID = deletedInterview.ApplicantID; 144. myAction.Description = String.Format("Interview with {0} has been deleted by {1}", deletedInterview.ApplicantID.ToString(), "default user"); 145. myAction.TimeStamp = DateTime.Now; 146. context.ActionHistories.Add(myAction); 147. context.SubmitChanges(); 148. } 149. , null); 150. } 151. 152. #region Appointment Helpers :) 153. 154. public Interview AppointmentToEntity(InterviewAppointment ia) 155. { 156. Interview newInterview = new Interview(); 157. newInterview.Subject = ia.Subject; 158. newInterview.Body = ia.Body; 159. newInterview.Start = ia.Start; 160. newInterview.End = ia.End; 161. newInterview.ApplicantID = ia.ApplicantID; 162. newInterview.PostingID = ia.PostingID; 163. newInterview.InterviewID = ia.InterviewID; 164. 165. return newInterview; 166. } 167. 168. public InterviewAppointment EntityToAppointment(Interview ia) 169. { 170. InterviewAppointment newInterview = new InterviewAppointment(); 171. newInterview.Subject = ia.Subject; 172. newInterview.Body = ia.Body; 173. newInterview.Start = ia.Start; 174. newInterview.End = ia.End; 175. newInterview.ApplicantID = ia.ApplicantID; 176. newInterview.PostingID = ia.PostingID; 177. newInterview.InterviewID = ia.InterviewID; 178. 179. return newInterview; 180. } 181. 182. public void CopyAppointmentEdit(Interview entityInterview, InterviewAppointment appointmentInterview) 183. { 184. entityInterview.Subject = appointmentInterview.Subject; 185. entityInterview.Body = appointmentInterview.Body; 186. entityInterview.Start = appointmentInterview.Start; 187. entityInterview.End = appointmentInterview.End; 188. entityInterview.ApplicantID = appointmentInterview.ApplicantID; 189. entityInterview.PostingID = appointmentInterview.PostingID; 190. } 191. 192. #endregion 193. 194. #region INotifyPropertyChanged Members 195. 196. public event PropertyChangedEventHandler PropertyChanged; 197. 198. public void NotifyChanged(string propertyName) 199. { 200. if (string.IsNullOrEmpty(propertyName)) 201. throw new ArgumentException("propertyName"); 202. 203. PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); 204. } 205. 206. #endregion 207.} Nice... right? :) One really important thing to note as well. See on line 51 where I set the DataContext before the Loaded event? This is super important, as if you don't have this set before the usercontrol is loaded, the DataContextProxy has no context to use and your EditAppointmentDialog Job/Applicant dropdowns will be blank and empty. Trust me on this, took a little bit of debugging to figure out that by setting the DataContext post-loaded would only lead to disaster and frustration. Otherwise, the only other real difference is that instead of sending an ActionHistory item through an event to get added to the database and saved, I do those right in the callback from submitting. The Result Again, I only have to post one picture because these bad boys used nearly identical code for both the MVVM and the code-behind views, so our end result is... So what have we learned here today? One, for the most part this MVVM thing is somewhat easy. Yeah, you sometimes have to write a bunch of extra code, but with the help of a few useful snippits you can turn the process into a pretty streamlined little workflow. Heck, this story gets even easier as you can see in this blog post by Michael Washington- specifically run a find on 'InvokeCommandAction' and you'll see the section regarding the command on TreeView in Blend 4. Brilliant! MVVM never looked so sweet! Otherwise, it is business as usual with RadScheduler for Silverlight whichever path you're choosing for your development. Between now and the next post, I'll be cleaning up styles a bit (those RadComboBoxes are a little too close to my labels!) and adding some to the RowDetailsViews for Applicants and Jobs, so you can see all the info for an appointment in the dropdown tab view. Otherwise, we're about ready to call a wrap on this oneDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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value types in the vm

- by john.rose

value types in the vm p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} p.p2 {margin: 0.0px 0.0px 14.0px 0.0px; font: 14.0px Times} p.p3 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times} p.p4 {margin: 0.0px 0.0px 15.0px 0.0px; font: 14.0px Times} p.p5 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier} p.p6 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Courier; min-height: 17.0px} p.p7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p8 {margin: 0.0px 0.0px 0.0px 36.0px; text-indent: -36.0px; font: 14.0px Times; min-height: 18.0px} p.p9 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; min-height: 18.0px} p.p10 {margin: 0.0px 0.0px 12.0px 0.0px; font: 14.0px Times; color: #000000} li.li1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times} li.li7 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px Times; min-height: 18.0px} span.s1 {font: 14.0px Courier} span.s2 {color: #000000} span.s3 {font: 14.0px Courier; color: #000000} ol.ol1 {list-style-type: decimal} Or, enduring values for a changing world. Introduction A value type is a data type which, generally speaking, is designed for being passed by value in and out of methods, and stored by value in data structures. The only value types which the Java language directly supports are the eight primitive types. Java indirectly and approximately supports value types, if they are implemented in terms of classes. For example, both Integer and String may be viewed as value types, especially if their usage is restricted to avoid operations appropriate to Object. In this note, we propose a definition of value types in terms of a design pattern for Java classes, accompanied by a set of usage restrictions. We also sketch the relation of such value types to tuple types (which are a JVM-level notion), and point out JVM optimizations that can apply to value types. This note is a thought experiment to extend the JVM’s performance model in support of value types. The demonstration has two phases. Initially the extension can simply use design patterns, within the current bytecode architecture, and in today’s Java language. But if the performance model is to be realized in practice, it will probably require new JVM bytecode features, changes to the Java language, or both. We will look at a few possibilities for these new features. An Axiom of Value In the context of the JVM, a value type is a data type equipped with construction, assignment, and equality operations, and a set of typed components, such that, whenever two variables of the value type produce equal corresponding values for their components, the values of the two variables cannot be distinguished by any JVM operation. Here are some corollaries: A value type is immutable, since otherwise a copy could be constructed and the original could be modified in one of its components, allowing the copies to be distinguished. Changing the component of a value type requires construction of a new value. The equals and hashCode operations are strictly component-wise. If a value type is represented by a JVM reference, that reference cannot be successfully synchronized on, and cannot be usefully compared for reference equality. A value type can be viewed in terms of what it doesn’t do. We can say that a value type omits all value-unsafe operations, which could violate the constraints on value types. These operations, which are ordinarily allowed for Java object types, are pointer equality comparison (the acmp instruction), synchronization (the monitor instructions), all the wait and notify methods of class Object, and non-trivial finalize methods. The clone method is also value-unsafe, although for value types it could be treated as the identity function. Finally, and most importantly, any side effect on an object (however visible) also counts as an value-unsafe operation. A value type may have methods, but such methods must not change the components of the value. It is reasonable and useful to define methods like toString, equals, and hashCode on value types, and also methods which are specifically valuable to users of the value type. Representations of Value Value types have two natural representations in the JVM, unboxed and boxed. An unboxed value consists of the components, as simple variables. For example, the complex number x=(1+2i), in rectangular coordinate form, may be represented in unboxed form by the following pair of variables: /*Complex x = Complex.valueOf(1.0, 2.0):*/ double x_re = 1.0, x_im = 2.0; These variables might be locals, parameters, or fields. Their association as components of a single value is not defined to the JVM. Here is a sample computation which computes the norm of the difference between two complex numbers: double distance(/*Complex x:*/ double x_re, double x_im, /*Complex y:*/ double y_re, double y_im) { /*Complex z = x.minus(y):*/ double z_re = x_re - y_re, z_im = x_im - y_im; /*return z.abs():*/ return Math.sqrt(z_re*z_re + z_im*z_im); } A boxed representation groups component values under a single object reference. The reference is to a ‘wrapper class’ that carries the component values in its fields. (A primitive type can naturally be equated with a trivial value type with just one component of that type. In that view, the wrapper class Integer can serve as a boxed representation of value type int.) The unboxed representation of complex numbers is practical for many uses, but it fails to cover several major use cases: return values, array elements, and generic APIs. The two components of a complex number cannot be directly returned from a Java function, since Java does not support multiple return values. The same story applies to array elements: Java has no ’array of structs’ feature. (Double-length arrays are a possible workaround for complex numbers, but not for value types with heterogeneous components.) By generic APIs I mean both those which use generic types, like Arrays.asList and those which have special case support for primitive types, like String.valueOf and PrintStream.println. Those APIs do not support unboxed values, and offer some problems to boxed values. Any ’real’ JVM type should have a story for returns, arrays, and API interoperability. The basic problem here is that value types fall between primitive types and object types. Value types are clearly more complex than primitive types, and object types are slightly too complicated. Objects are a little bit dangerous to use as value carriers, since object references can be compared for pointer equality, and can be synchronized on. Also, as many Java programmers have observed, there is often a performance cost to using wrapper objects, even on modern JVMs. Even so, wrapper classes are a good starting point for talking about value types. If there were a set of structural rules and restrictions which would prevent value-unsafe operations on value types, wrapper classes would provide a good notation for defining value types. This note attempts to define such rules and restrictions. Let’s Start Coding Now it is time to look at some real code. Here is a definition, written in Java, of a complex number value type. @ValueSafe public final class Complex implements java.io.Serializable { // immutable component structure: public final double re, im; private Complex(double re, double im) { this.re = re; this.im = im; } // interoperability methods: public String toString() { return "Complex("+re+","+im+")"; } public List<Double> asList() { return Arrays.asList(re, im); } public boolean equals(Complex c) { return re == c.re && im == c.im; } public boolean equals(@ValueSafe Object x) { return x instanceof Complex && equals((Complex) x); } public int hashCode() { return 31*Double.valueOf(re).hashCode() + Double.valueOf(im).hashCode(); } // factory methods: public static Complex valueOf(double re, double im) { return new Complex(re, im); } public Complex changeRe(double re2) { return valueOf(re2, im); } public Complex changeIm(double im2) { return valueOf(re, im2); } public static Complex cast(@ValueSafe Object x) { return x == null ? ZERO : (Complex) x; } // utility methods and constants: public Complex plus(Complex c) { return new Complex(re+c.re, im+c.im); } public Complex minus(Complex c) { return new Complex(re-c.re, im-c.im); } public double abs() { return Math.sqrt(re*re + im*im); } public static final Complex PI = valueOf(Math.PI, 0.0); public static final Complex ZERO = valueOf(0.0, 0.0); } This is not a minimal definition, because it includes some utility methods and other optional parts. The essential elements are as follows: The class is marked as a value type with an annotation. The class is final, because it does not make sense to create subclasses of value types. The fields of the class are all non-private and final. (I.e., the type is immutable and structurally transparent.) From the supertype Object, all public non-final methods are overridden. The constructor is private. Beyond these bare essentials, we can observe the following features in this example, which are likely to be typical of all value types: One or more factory methods are responsible for value creation, including a component-wise valueOf method. There are utility methods for complex arithmetic and instance creation, such as plus and changeIm. There are static utility constants, such as PI. The type is serializable, using the default mechanisms. There are methods for converting to and from dynamically typed references, such as asList and cast. The Rules In order to use value types properly, the programmer must avoid value-unsafe operations. A helpful Java compiler should issue errors (or at least warnings) for code which provably applies value-unsafe operations, and should issue warnings for code which might be correct but does not provably avoid value-unsafe operations. No such compilers exist today, but to simplify our account here, we will pretend that they do exist. A value-safe type is any class, interface, or type parameter marked with the @ValueSafe annotation, or any subtype of a value-safe type. If a value-safe class is marked final, it is in fact a value type. All other value-safe classes must be abstract. The non-static fields of a value class must be non-public and final, and all its constructors must be private. Under the above rules, a standard interface could be helpful to define value types like Complex. Here is an example: @ValueSafe public interface ValueType extends java.io.Serializable { // All methods listed here must get redefined. // Definitions must be value-safe, which means // they may depend on component values only. List<? extends Object> asList(); int hashCode(); boolean equals(@ValueSafe Object c); String toString(); } //@ValueSafe inherited from supertype: public final class Complex implements ValueType { … The main advantage of such a conventional interface is that (unlike an annotation) it is reified in the runtime type system. It could appear as an element type or parameter bound, for facilities which are designed to work on value types only. More broadly, it might assist the JVM to perform dynamic enforcement of the rules for value types. Besides types, the annotation @ValueSafe can mark fields, parameters, local variables, and methods. (This is redundant when the type is also value-safe, but may be useful when the type is Object or another supertype of a value type.) Working forward from these annotations, an expression E is defined as value-safe if it satisfies one or more of the following: The type of E is a value-safe type. E names a field, parameter, or local variable whose declaration is marked @ValueSafe. E is a call to a method whose declaration is marked @ValueSafe. E is an assignment to a value-safe variable, field reference, or array reference. E is a cast to a value-safe type from a value-safe expression. E is a conditional expression E0 ? E1 : E2, and both E1 and E2 are value-safe. Assignments to value-safe expressions and initializations of value-safe names must take their values from value-safe expressions. A value-safe expression may not be the subject of a value-unsafe operation. In particular, it cannot be synchronized on, nor can it be compared with the “==” operator, not even with a null or with another value-safe type. In a program where all of these rules are followed, no value-type value will be subject to a value-unsafe operation. Thus, the prime axiom of value types will be satisfied, that no two value type will be distinguishable as long as their component values are equal. More Code To illustrate these rules, here are some usage examples for Complex: Complex pi = Complex.valueOf(Math.PI, 0); Complex zero = pi.changeRe(0); //zero = pi; zero.re = 0; ValueType vtype = pi; @SuppressWarnings("value-unsafe") Object obj = pi; @ValueSafe Object obj2 = pi; obj2 = new Object(); // ok List<Complex> clist = new ArrayList<Complex>(); clist.add(pi); // (ok assuming List.add param is @ValueSafe) List<ValueType> vlist = new ArrayList<ValueType>(); vlist.add(pi); // (ok) List<Object> olist = new ArrayList<Object>(); olist.add(pi); // warning: "value-unsafe" boolean z = pi.equals(zero); boolean z1 = (pi == zero); // error: reference comparison on value type boolean z2 = (pi == null); // error: reference comparison on value type boolean z3 = (pi == obj2); // error: reference comparison on value type synchronized (pi) { } // error: synch of value, unpredictable result synchronized (obj2) { } // unpredictable result Complex qq = pi; qq = null; // possible NPE; warning: “null-unsafe" qq = (Complex) obj; // warning: “null-unsafe" qq = Complex.cast(obj); // OK @SuppressWarnings("null-unsafe") Complex empty = null; // possible NPE qq = empty; // possible NPE (null pollution) The Payoffs It follows from this that either the JVM or the java compiler can replace boxed value-type values with unboxed ones, without affecting normal computations. Fields and variables of value types can be split into their unboxed components. Non-static methods on value types can be transformed into static methods which take the components as value parameters. Some common questions arise around this point in any discussion of value types. Why burden the programmer with all these extra rules? Why not detect programs automagically and perform unboxing transparently? The answer is that it is easy to break the rules accidently unless they are agreed to by the programmer and enforced. Automatic unboxing optimizations are tantalizing but (so far) unreachable ideal. In the current state of the art, it is possible exhibit benchmarks in which automatic unboxing provides the desired effects, but it is not possible to provide a JVM with a performance model that assures the programmer when unboxing will occur. This is why I’m writing this note, to enlist help from, and provide assurances to, the programmer. Basically, I’m shooting for a good set of user-supplied “pragmas” to frame the desired optimization. Again, the important thing is that the unboxing must be done reliably, or else programmers will have no reason to work with the extra complexity of the value-safety rules. There must be a reasonably stable performance model, wherein using a value type has approximately the same performance characteristics as writing the unboxed components as separate Java variables. There are some rough corners to the present scheme. Since Java fields and array elements are initialized to null, value-type computations which incorporate uninitialized variables can produce null pointer exceptions. One workaround for this is to require such variables to be null-tested, and the result replaced with a suitable all-zero value of the value type. That is what the “cast” method does above. Generically typed APIs like List<T> will continue to manipulate boxed values always, at least until we figure out how to do reification of generic type instances. Use of such APIs will elicit warnings until their type parameters (and/or relevant members) are annotated or typed as value-safe. Retrofitting List<T> is likely to expose flaws in the present scheme, which we will need to engineer around. Here are a couple of first approaches: public interface java.util.List<@ValueSafe T> extends Collection<T> { … public interface java.util.List<T extends Object|ValueType> extends Collection<T> { … (The second approach would require disjunctive types, in which value-safety is “contagious” from the constituent types.) With more transformations, the return value types of methods can also be unboxed. This may require significant bytecode-level transformations, and would work best in the presence of a bytecode representation for multiple value groups, which I have proposed elsewhere under the title “Tuples in the VM”. But for starters, the JVM can apply this transformation under the covers, to internally compiled methods. This would give a way to express multiple return values and structured return values, which is a significant pain-point for Java programmers, especially those who work with low-level structure types favored by modern vector and graphics processors. The lack of multiple return values has a strong distorting effect on many Java APIs. Even if the JVM fails to unbox a value, there is still potential benefit to the value type. Clustered computing systems something have copy operations (serialization or something similar) which apply implicitly to command operands. When copying JVM objects, it is extremely helpful to know when an object’s identity is important or not. If an object reference is a copied operand, the system may have to create a proxy handle which points back to the original object, so that side effects are visible. Proxies must be managed carefully, and this can be expensive. On the other hand, value types are exactly those types which a JVM can “copy and forget” with no downside. Array types are crucial to bulk data interfaces. (As data sizes and rates increase, bulk data becomes more important than scalar data, so arrays are definitely accompanying us into the future of computing.) Value types are very helpful for adding structure to bulk data, so a successful value type mechanism will make it easier for us to express richer forms of bulk data. Unboxing arrays (i.e., arrays containing unboxed values) will provide better cache and memory density, and more direct data movement within clustered or heterogeneous computing systems. They require the deepest transformations, relative to today’s JVM. There is an impedance mismatch between value-type arrays and Java’s covariant array typing, so compromises will need to be struck with existing Java semantics. It is probably worth the effort, since arrays of unboxed value types are inherently more memory-efficient than standard Java arrays, which rely on dependent pointer chains. It may be sufficient to extend the “value-safe” concept to array declarations, and allow low-level transformations to change value-safe array declarations from the standard boxed form into an unboxed tuple-based form. Such value-safe arrays would not be convertible to Object[] arrays. Certain connection points, such as Arrays.copyOf and System.arraycopy might need additional input/output combinations, to allow smooth conversion between arrays with boxed and unboxed elements. Alternatively, the correct solution may have to wait until we have enough reification of generic types, and enough operator overloading, to enable an overhaul of Java arrays. Implicit Method Definitions The example of class Complex above may be unattractively complex. I believe most or all of the elements of the example class are required by the logic of value types. If this is true, a programmer who writes a value type will have to write lots of error-prone boilerplate code. On the other hand, I think nearly all of the code (except for the domain-specific parts like plus and minus) can be implicitly generated. Java has a rule for implicitly defining a class’s constructor, if no it defines no constructors explicitly. Likewise, there are rules for providing default access modifiers for interface members. Because of the highly regular structure of value types, it might be reasonable to perform similar implicit transformations on value types. Here’s an example of a “highly implicit” definition of a complex number type: public class Complex implements ValueType { // implicitly final public double re, im; // implicitly public final //implicit methods are defined elementwise from te fields: // toString, asList, equals(2), hashCode, valueOf, cast //optionally, explicit methods (plus, abs, etc.) would go here } In other words, with the right defaults, a simple value type definition can be a one-liner. The observant reader will have noticed the similarities (and suitable differences) between the explicit methods above and the corresponding methods for List<T>. Another way to abbreviate such a class would be to make an annotation the primary trigger of the functionality, and to add the interface(s) implicitly: public @ValueType class Complex { … // implicitly final, implements ValueType (But to me it seems better to communicate the “magic” via an interface, even if it is rooted in an annotation.) Implicitly Defined Value Types So far we have been working with nominal value types, which is to say that the sequence of typed components is associated with a name and additional methods that convey the intention of the programmer. A simple ordered pair of floating point numbers can be variously interpreted as (to name a few possibilities) a rectangular or polar complex number or Cartesian point. The name and the methods convey the intended meaning. But what if we need a truly simple ordered pair of floating point numbers, without any further conceptual baggage? Perhaps we are writing a method (like “divideAndRemainder”) which naturally returns a pair of numbers instead of a single number. Wrapping the pair of numbers in a nominal type (like “QuotientAndRemainder”) makes as little sense as wrapping a single return value in a nominal type (like “Quotient”). What we need here are structural value types commonly known as tuples. For the present discussion, let us assign a conventional, JVM-friendly name to tuples, roughly as follows: public class java.lang.tuple.$DD extends java.lang.tuple.Tuple { double $1, $2; } Here the component names are fixed and all the required methods are defined implicitly. The supertype is an abstract class which has suitable shared declarations. The name itself mentions a JVM-style method parameter descriptor, which may be “cracked” to determine the number and types of the component fields. The odd thing about such a tuple type (and structural types in general) is it must be instantiated lazily, in response to linkage requests from one or more classes that need it. The JVM and/or its class loaders must be prepared to spin a tuple type on demand, given a simple name reference, $xyz, where the xyz is cracked into a series of component types. (Specifics of naming and name mangling need some tasteful engineering.) Tuples also seem to demand, even more than nominal types, some support from the language. (This is probably because notations for non-nominal types work best as combinations of punctuation and type names, rather than named constructors like Function3 or Tuple2.) At a minimum, languages with tuples usually (I think) have some sort of simple bracket notation for creating tuples, and a corresponding pattern-matching syntax (or “destructuring bind”) for taking tuples apart, at least when they are parameter lists. Designing such a syntax is no simple thing, because it ought to play well with nominal value types, and also with pre-existing Java features, such as method parameter lists, implicit conversions, generic types, and reflection. That is a task for another day. Other Use Cases Besides complex numbers and simple tuples there are many use cases for value types. Many tuple-like types have natural value-type representations. These include rational numbers, point locations and pixel colors, and various kinds of dates and addresses. Other types have a variable-length ‘tail’ of internal values. The most common example of this is String, which is (mathematically) a sequence of UTF-16 character values. Similarly, bit vectors, multiple-precision numbers, and polynomials are composed of sequences of values. Such types include, in their representation, a reference to a variable-sized data structure (often an array) which (somehow) represents the sequence of values. The value type may also include ’header’ information. Variable-sized values often have a length distribution which favors short lengths. In that case, the design of the value type can make the first few values in the sequence be direct ’header’ fields of the value type. In the common case where the header is enough to represent the whole value, the tail can be a shared null value, or even just a null reference. Note that the tail need not be an immutable object, as long as the header type encapsulates it well enough. This is the case with String, where the tail is a mutable (but never mutated) character array. Field types and their order must be a globally visible part of the API. The structure of the value type must be transparent enough to have a globally consistent unboxed representation, so that all callers and callees agree about the type and order of components that appear as parameters, return types, and array elements. This is a trade-off between efficiency and encapsulation, which is forced on us when we remove an indirection enjoyed by boxed representations. A JVM-only transformation would not care about such visibility, but a bytecode transformation would need to take care that (say) the components of complex numbers would not get swapped after a redefinition of Complex and a partial recompile. Perhaps constant pool references to value types need to declare the field order as assumed by each API user. This brings up the delicate status of private fields in a value type. It must always be possible to load, store, and copy value types as coordinated groups, and the JVM performs those movements by moving individual scalar values between locals and stack. If a component field is not public, what is to prevent hostile code from plucking it out of the tuple using a rogue aload or astore instruction? Nothing but the verifier, so we may need to give it more smarts, so that it treats value types as inseparable groups of stack slots or locals (something like long or double). My initial thought was to make the fields always public, which would make the security problem moot. But public is not always the right answer; consider the case of String, where the underlying mutable character array must be encapsulated to prevent security holes. I believe we can win back both sides of the tradeoff, by training the verifier never to split up the components in an unboxed value. Just as the verifier encapsulates the two halves of a 64-bit primitive, it can encapsulate the the header and body of an unboxed String, so that no code other than that of class String itself can take apart the values. Similar to String, we could build an efficient multi-precision decimal type along these lines: public final class DecimalValue extends ValueType { protected final long header; protected private final BigInteger digits; public DecimalValue valueOf(int value, int scale) { assert(scale >= 0); return new DecimalValue(((long)value << 32) + scale, null); } public DecimalValue valueOf(long value, int scale) { if (value == (int) value) return valueOf((int)value, scale); return new DecimalValue(-scale, new BigInteger(value)); } } Values of this type would be passed between methods as two machine words. Small values (those with a significand which fits into 32 bits) would be represented without any heap data at all, unless the DecimalValue itself were boxed. (Note the tension between encapsulation and unboxing in this case. It would be better if the header and digits fields were private, but depending on where the unboxing information must “leak”, it is probably safer to make a public revelation of the internal structure.) Note that, although an array of Complex can be faked with a double-length array of double, there is no easy way to fake an array of unboxed DecimalValues. (Either an array of boxed values or a transposed pair of homogeneous arrays would be reasonable fallbacks, in a current JVM.) Getting the full benefit of unboxing and arrays will require some new JVM magic. Although the JVM emphasizes portability, system dependent code will benefit from using machine-level types larger than 64 bits. For example, the back end of a linear algebra package might benefit from value types like Float4 which map to stock vector types. This is probably only worthwhile if the unboxing arrays can be packed with such values. More Daydreams A more finely-divided design for dynamic enforcement of value safety could feature separate marker interfaces for each invariant. An empty marker interface Unsynchronizable could cause suitable exceptions for monitor instructions on objects in marked classes. More radically, a Interchangeable marker interface could cause JVM primitives that are sensitive to object identity to raise exceptions; the strangest result would be that the acmp instruction would have to be specified as raising an exception. @ValueSafe public interface ValueType extends java.io.Serializable, Unsynchronizable, Interchangeable { … public class Complex implements ValueType { // inherits Serializable, Unsynchronizable, Interchangeable, @ValueSafe … It seems possible that Integer and the other wrapper types could be retro-fitted as value-safe types. This is a major change, since wrapper objects would be unsynchronizable and their references interchangeable. It is likely that code which violates value-safety for wrapper types exists but is uncommon. It is less plausible to retro-fit String, since the prominent operation String.intern is often used with value-unsafe code. We should also reconsider the distinction between boxed and unboxed values in code. The design presented above obscures that distinction. As another thought experiment, we could imagine making a first class distinction in the type system between boxed and unboxed representations. Since only primitive types are named with a lower-case initial letter, we could define that the capitalized version of a value type name always refers to the boxed representation, while the initial lower-case variant always refers to boxed. For example: complex pi = complex.valueOf(Math.PI, 0); Complex boxPi = pi; // convert to boxed myList.add(boxPi); complex z = myList.get(0); // unbox Such a convention could perhaps absorb the current difference between int and Integer, double and Double. It might also allow the programmer to express a helpful distinction among array types. As said above, array types are crucial to bulk data interfaces, but are limited in the JVM. Extending arrays beyond the present limitations is worth thinking about; for example, the Maxine JVM implementation has a hybrid object/array type. Something like this which can also accommodate value type components seems worthwhile. On the other hand, does it make sense for value types to contain short arrays? And why should random-access arrays be the end of our design process, when bulk data is often sequentially accessed, and it might make sense to have heterogeneous streams of data as the natural “jumbo” data structure. These considerations must wait for another day and another note. More Work It seems to me that a good sequence for introducing such value types would be as follows: Add the value-safety restrictions to an experimental version of javac. Code some sample applications with value types, including Complex and DecimalValue. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so. Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. A staggered roll-out like this would decouple language changes from bytecode changes, which is always a convenient thing. A similar investigation should be applied (concurrently) to array types. In this case, it seems to me that the starting point is in the JVM: Add an experimental unboxing array data structure to a production JVM, perhaps along the lines of Maxine hybrids. No bytecode or language support is required at first; everything can be done with encapsulated unsafe operations and/or method handles. Create an experimental JVM which internally unboxes value types but does not require new bytecodes to do so. Ensure the feasibility of the performance model for the sample applications. Add tuple-like bytecodes (with or without generic type reification) to a major revision of the JVM, and teach the Java compiler to switch in the new bytecodes without code changes. That’s enough musing me for now. Back to work!

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Building applications with WCF - Intro

- by skjagini

I am going to write series of articles using Windows Communication Framework (WCF) to develop client and server applications and this is the first part of that series. What is WCF As Juwal puts in his Programming WCF book, WCF provides an SDK for developing and deploying services on Windows, provides runtime environment to expose CLR types as services and consume services as CLR types. Building services with WCF is incredibly easy and it’s implementation provides a set of industry standards and off the shelf plumbing including service hosting, instance management, reliability, transaction management, security etc such that it greatly increases productivity Scenario: Lets consider a typical bank customer trying to create an account, deposit amount and transfer funds between accounts, i.e. checking and savings. To make it interesting, we are going to divide the functionality into multiple services and each of them working with database directly. We will run test cases with and without transactional support across services. In this post we will build contracts, services, data access layer, unit tests to verify end to end communication etc, nothing big stuff here and we dig into other features of the WCF in subsequent posts with incremental changes. In any distributed architecture we have two pieces i.e. services and clients. Services as the name implies provide functionality to execute various pieces of business logic on the server, and clients providing interaction to the end user. Services can be built with Web Services or with WCF. Service built on WCF have the advantage of binding independent, i.e. can run against TCP and HTTP protocol without any significant changes to the code. Solution Services Profile: For creating a new bank customer, getting details about existing customer ProfileContract ProfileService Checking Account: To get checking account balance, deposit or withdraw amount CheckingAccountContract CheckingAccountService Savings Account: To get savings account balance, deposit or withdraw amount SavingsAccountContract SavingsAccountService ServiceHost: To host services, i.e. running the services at particular address, binding and contract where client can connect to Client: Helps end user to use services like creating account and amount transfer between the accounts BankDAL: Data access layer to work with database BankDAL It’s no brainer not to use an ORM as many matured products are available currently in market including Linq2Sql, Entity Framework (EF), LLblGenPro etc. For this exercise I am going to use Entity Framework 4.0, CTP 5 with code first approach. There are two approaches when working with data, data driven and code driven. In data driven we start by designing tables and their constrains in database and generate entities in code while in code driven (code first) approach entities are defined in code and the metadata generated from the entities is used by the EF to create tables and table constrains. In previous versions the entity classes had to derive from EF specific base classes. In EF 4 it is not required to derive from any EF classes, the entities are not only persistence ignorant but also enable full test driven development using mock frameworks. Application consists of 3 entities, Customer entity which contains Customer details; CheckingAccount and SavingsAccount to hold the respective account balance. We could have introduced an Account base class for CheckingAccount and SavingsAccount which is certainly possible with EF mappings but to keep it simple we are just going to follow 1 –1 mapping between entity and table mappings. Lets start out by defining a class called Customer which will be mapped to Customer table, observe that the class is simply a plain old clr object (POCO) and has no reference to EF at all. using System; namespace BankDAL.Model { public class Customer { public int Id { get; set; } public string FullName { get; set; } public string Address { get; set; } public DateTime DateOfBirth { get; set; } } } In order to inform EF about the Customer entity we have to define a database context with properties of type DbSet<> for every POCO which needs to be mapped to a table in database. EF uses convention over configuration to generate the metadata resulting in much less configuration. using System.Data.Entity; namespace BankDAL.Model { public class BankDbContext: DbContext { public DbSet<Customer> Customers { get; set; } } } Entity constrains can be defined through attributes on Customer class or using fluent syntax (no need to muscle with xml files), CustomerConfiguration class. By defining constrains in a separate class we can maintain clean POCOs without corrupting entity classes with database specific information. using System; using System.Data.Entity.ModelConfiguration; namespace BankDAL.Model { public class CustomerConfiguration: EntityTypeConfiguration<Customer> { public CustomerConfiguration() { Initialize(); } private void Initialize() { //Setting the Primary Key this.HasKey(e => e.Id); //Setting required fields this.HasRequired(e => e.FullName); this.HasRequired(e => e.Address); //Todo: Can't create required constraint as DateOfBirth is not reference type, research it //this.HasRequired(e => e.DateOfBirth); } } } Any queries executed against Customers property in BankDbContext are executed against Cusomers table. By convention EF looks for connection string with key of BankDbContext when working with the context. We are going to define a helper class to work with Customer entity with methods for querying, adding new entity etc and these are known as repository classes, i.e., CustomerRepository using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CustomerRepository { private readonly IDbSet<Customer> _customers; public CustomerRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _customers = bankDbContext.Customers; } public IQueryable<Customer> Query() { return _customers; } public void Add(Customer customer) { _customers.Add(customer); } } } From the above code it is observable that the Query methods returns customers as IQueryable i.e. customers are retrieved only when actually used i.e. iterated. Returning as IQueryable also allows to execute filtering and joining statements from business logic using lamba expressions without cluttering the data access layer with tens of methods. Our CheckingAccountRepository and SavingsAccountRepository look very similar to each other using System; using System.Data.Entity; using System.Linq; using BankDAL.Model; namespace BankDAL.Repositories { public class CheckingAccountRepository { private readonly IDbSet<CheckingAccount> _checkingAccounts; public CheckingAccountRepository(BankDbContext bankDbContext) { if (bankDbContext == null) throw new ArgumentNullException(); _checkingAccounts = bankDbContext.CheckingAccounts; } public IQueryable<CheckingAccount> Query() { return _checkingAccounts; } public void Add(CheckingAccount account) { _checkingAccounts.Add(account); } public IQueryable<CheckingAccount> GetAccount(int customerId) { return (from act in _checkingAccounts where act.CustomerId == customerId select act); } } } The repository classes look very similar to each other for Query and Add methods, with the help of C# generics and implementing repository pattern (Martin Fowler) we can reduce the repeated code. Jarod from ElegantCode has posted an article on how to use repository pattern with EF which we will implement in the subsequent articles along with WCF Unity life time managers by Drew Contracts It is very easy to follow contract first approach with WCF, define the interface and append ServiceContract, OperationContract attributes. IProfile contract exposes functionality for creating customer and getting customer details. using System; using System.ServiceModel; using BankDAL.Model; namespace ProfileContract { [ServiceContract] public interface IProfile { [OperationContract] Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth); [OperationContract] Customer GetCustomer(int id); } } ICheckingAccount contract exposes functionality for working with checking account, i.e., getting balance, deposit and withdraw of amount. ISavingsAccount contract looks the same as checking account. using System.ServiceModel; namespace CheckingAccountContract { [ServiceContract] public interface ICheckingAccount { [OperationContract] decimal? GetCheckingAccountBalance(int customerId); [OperationContract] void DepositAmount(int customerId,decimal amount); [OperationContract] void WithdrawAmount(int customerId, decimal amount); } } Services Having covered the data access layer and contracts so far and here comes the core of the business logic, i.e. services. .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } ProfileService implements the IProfile contract for creating customer and getting customer detail using CustomerRepository. using System; using System.Linq; using System.ServiceModel; using BankDAL; using BankDAL.Model; using BankDAL.Repositories; using ProfileContract; namespace ProfileService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Profile: IProfile { public Customer CreateAccount( string customerName, string address, DateTime dateOfBirth) { Customer cust = new Customer { FullName = customerName, Address = address, DateOfBirth = dateOfBirth }; using (var bankDbContext = new BankDbContext()) { new CustomerRepository(bankDbContext).Add(cust); bankDbContext.SaveChanges(); } return cust; } public Customer CreateCustomer(string customerName, string address, DateTime dateOfBirth) { return CreateAccount(customerName, address, dateOfBirth); } public Customer GetCustomer(int id) { return new CustomerRepository(new BankDbContext()).Query() .Where(i => i.Id == id).FirstOrDefault(); } } } From the above code you shall observe that we are calling bankDBContext’s SaveChanges method and there is no save method specific to customer entity because EF manages all the changes centralized at the context level and all the pending changes so far are submitted in a batch and it is represented as Unit of Work. Similarly Checking service implements ICheckingAccount contract using CheckingAccountRepository, notice that we are throwing overdraft exception if the balance falls by zero. WCF has it’s own way of raising exceptions using fault contracts which will be explained in the subsequent articles. SavingsAccountService is similar to CheckingAccountService. using System; using System.Linq; using System.ServiceModel; using BankDAL.Model; using BankDAL.Repositories; using CheckingAccountContract; namespace CheckingAccountService { [ServiceBehavior(IncludeExceptionDetailInFaults = true)] public class Checking:ICheckingAccount { public decimal? GetCheckingAccountBalance(int customerId) { using (var bankDbContext = new BankDbContext()) { CheckingAccount account = (new CheckingAccountRepository(bankDbContext) .GetAccount(customerId)).FirstOrDefault(); if (account != null) return account.Balance; return null; } } public void DepositAmount(int customerId, decimal amount) { using(var bankDbContext = new BankDbContext()) { var checkingAccountRepository = new CheckingAccountRepository(bankDbContext); CheckingAccount account = (checkingAccountRepository.GetAccount(customerId)) .FirstOrDefault(); if (account == null) { account = new CheckingAccount() { CustomerId = customerId }; checkingAccountRepository.Add(account); } account.Balance = account.Balance + amount; if (account.Balance < 0) throw new ApplicationException("Overdraft not accepted"); bankDbContext.SaveChanges(); } } public void WithdrawAmount(int customerId, decimal amount) { DepositAmount(customerId, -1*amount); } } } BankServiceHost The host acts as a glue binding contracts with it’s services, exposing the endpoints. The services can be exposed either through the code or configuration file, configuration file is preferred as it allows run time changes to service behavior even after deployment. We have 3 services and for each of the service you need to define name (the class that implements the service with fully qualified namespace) and endpoint known as ABC, i.e. address, binding and contract. We are using netTcpBinding and have defined the base address with for each of the contracts .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } <system.serviceModel> <services> <service name="ProfileService.Profile"> <endpoint binding="netTcpBinding" contract="ProfileContract.IProfile"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Profile"/> </baseAddresses> </host> </service> <service name="CheckingAccountService.Checking"> <endpoint binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Checking"/> </baseAddresses> </host> </service> <service name="SavingsAccountService.Savings"> <endpoint binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> <host> <baseAddresses> <add baseAddress="net.tcp://localhost:1000/Savings"/> </baseAddresses> </host> </service> </services> </system.serviceModel> Have to open the services by creating service host which will handle the incoming requests from clients. using System; namespace ServiceHost { class Program { static void Main(string[] args) { CreateHosts(); Console.ReadLine(); } private static void CreateHosts() { CreateHost(typeof(ProfileService.Profile),"Profile Service"); CreateHost(typeof(SavingsAccountService.Savings), "Savings Account Service"); CreateHost(typeof(CheckingAccountService.Checking), "Checking Account Service"); } private static void CreateHost(Type type, string hostDescription) { System.ServiceModel.ServiceHost host = new System.ServiceModel.ServiceHost(type); host.Open(); if (host.ChannelDispatchers != null && host.ChannelDispatchers.Count != 0 && host.ChannelDispatchers[0].Listener != null) Console.WriteLine("Started: " + host.ChannelDispatchers[0].Listener.Uri); else Console.WriteLine("Failed to start:" + hostDescription); } } } BankClient The client has no knowledge about service business logic other than the functionality it exposes through the contract, end points and a proxy to work against. The endpoint data and server proxy can be generated by right clicking on the project reference and choosing ‘Add Service Reference’ and entering the service end point address. Or if you have access to source, you can manually reference contract dlls and update clients configuration file to point to the service end point if the server and client happens to be being built using .Net framework. One of the pros with the manual approach is you don’t have to work against messy code generated files. <system.serviceModel> <client> <endpoint name="tcpProfile" address="net.tcp://localhost:1000/Profile" binding="netTcpBinding" contract="ProfileContract.IProfile"/> <endpoint name="tcpCheckingAccount" address="net.tcp://localhost:1000/Checking" binding="netTcpBinding" contract="CheckingAccountContract.ICheckingAccount"/> <endpoint name="tcpSavingsAccount" address="net.tcp://localhost:1000/Savings" binding="netTcpBinding" contract="SavingsAccountContract.ISavingsAccount"/> </client> </system.serviceModel> The client uses a façade to connect to the services using System.ServiceModel; using CheckingAccountContract; using ProfileContract; using SavingsAccountContract; namespace Client { public class ProxyFacade { public static IProfile ProfileProxy() { return (new ChannelFactory<IProfile>("tcpProfile")).CreateChannel(); } public static ICheckingAccount CheckingAccountProxy() { return (new ChannelFactory<ICheckingAccount>("tcpCheckingAccount")) .CreateChannel(); } public static ISavingsAccount SavingsAccountProxy() { return (new ChannelFactory<ISavingsAccount>("tcpSavingsAccount")) .CreateChannel(); } } } With that in place, lets get our unit tests going using System; using System.Diagnostics; using BankDAL.Model; using NUnit.Framework; using ProfileContract; namespace Client { [TestFixture] public class Tests { private void TransferFundsFromSavingsToCheckingAccount(int customerId, decimal amount) { ProxyFacade.CheckingAccountProxy().DepositAmount(customerId, amount); ProxyFacade.SavingsAccountProxy().WithdrawAmount(customerId, amount); } private void TransferFundsFromCheckingToSavingsAccount(int customerId, decimal amount) { ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, amount); ProxyFacade.CheckingAccountProxy().WithdrawAmount(customerId, amount); } [Test] public void CreateAndGetProfileTest() { IProfile profile = ProxyFacade.ProfileProxy(); const string customerName = "Tom"; int customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)).Id; Customer customer = profile.GetCustomer(customerId); Assert.AreEqual(customerName,customer.FullName); } [Test] public void DepositWithDrawAndTransferAmountTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Smith" + DateTime.Now.ToString("HH:mm:ss"); var customer = profile.CreateCustomer(customerName, "NJ", new DateTime(1982, 1, 1)); // Deposit to Savings ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 100); ProxyFacade.SavingsAccountProxy().DepositAmount(customer.Id, 25); Assert.AreEqual(125, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Withdraw ProxyFacade.SavingsAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(95, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); // Deposit to Checking ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 60); ProxyFacade.CheckingAccountProxy().DepositAmount(customer.Id, 40); Assert.AreEqual(100, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Withdraw ProxyFacade.CheckingAccountProxy().WithdrawAmount(customer.Id, 30); Assert.AreEqual(70, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Savings to Checking TransferFundsFromSavingsToCheckingAccount(customer.Id,10); Assert.AreEqual(85, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); // Transfer from Checking to Savings TransferFundsFromCheckingToSavingsAccount(customer.Id, 50); Assert.AreEqual(135, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customer.Id)); Assert.AreEqual(30, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customer.Id)); } [Test] public void FundTransfersWithOverDraftTest() { IProfile profile = ProxyFacade.ProfileProxy(); string customerName = "Angelina" + DateTime.Now.ToString("HH:mm:ss"); var customerId = profile.CreateCustomer(customerName, "NJ", new DateTime(1972, 1, 1)).Id; ProxyFacade.SavingsAccountProxy().DepositAmount(customerId, 100); TransferFundsFromSavingsToCheckingAccount(customerId,80); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); Assert.AreEqual(80, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); try { TransferFundsFromSavingsToCheckingAccount(customerId,30); } catch (Exception e) { Debug.WriteLine(e.Message); } Assert.AreEqual(110, ProxyFacade.CheckingAccountProxy().GetCheckingAccountBalance(customerId)); Assert.AreEqual(20, ProxyFacade.SavingsAccountProxy().GetSavingsAccountBalance(customerId)); } } } We are creating a new instance of the channel for every operation, we will look into instance management and how creating a new instance of channel affects it in subsequent articles. The first two test cases deals with creation of Customer, deposit and withdraw of month between accounts. The last case, FundTransferWithOverDraftTest() is interesting. Customer starts with depositing $100 in SavingsAccount followed by transfer of $80 in to checking account resulting in $20 in savings account. Customer then initiates $30 transfer from Savings to Checking resulting in overdraft exception on Savings with $30 being deposited to Checking. As we are not running both the requests in transactions the customer ends up with more amount than what he started with $100. In subsequent posts we will look into transactions handling. Make sure the ServiceHost project is set as start up project and start the solution. Run the test cases either from NUnit client or TestDriven.Net/Resharper which ever is your favorite tool. Make sure you have updated the data base connection string in the ServiceHost config file to point to your local database

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I need help on my C++ assignment using MS Visual C++

- by krayzwytie

Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This includes mostly //comments and what I have written so far. If you can help me figure out where all the errors are and how to complete the assignment, I will really appreciate it. Like I said, I don't want you to do my homework for me (it's my final), but any constructive criticism is welcome. This is my final assignment for this class and it is due tomorrow (Sunday before midnight, Arizona time). This is the assignment: Examine the following situation: o Your company, Datamax, Inc., is in the process of automating its payroll systems. Your manager has asked you to create a program that calculates overtime pay for all employees. Your program must take into account the employee’s salary, total hours worked, and hours worked more than 40 in a week, and then provide an output that is useful and easily understood by company management. • Compile your program utilizing the following background information and the code outline in Appendix D (included in the code section). • Submit your project as an attachment including the code and the output. Company Background: o Three employees: Mark, John, and Mary o The end user needs to be prompted for three specific pieces of input—name, hours worked, and hourly wage. o Calculate overtime if input is greater than 40 hours per week. o Provide six test plans to verify the logic within the program. o Plan 1 must display the proper information for employee #1 with overtime pay. o Plan 2 must display the proper information for employee #1 with no overtime pay. o Plans 3-6 are duplicates of plan 1 and 2 but for the other employees. Program Requirements: o Define a base class to use for the entire program. o The class holds the function calls and the variables related to the overtime pay calculations. o Define one object per employee. Note there will be three employees. o Your program must take the objects created and implement calculations based on total salaries, total hours, and the total number of overtime hours. See the Employee Summary Data section of the sample output. Logic Steps to Complete Your Program: o Define your base class. o Define your objects from your base class. o Prompt for user input, updating your object classes for all three users. o Implement your overtime pay calculations. o Display overtime or regular time pay calculations. See the sample output below. o Implement object calculations by summarizing your employee objects and display the summary information in the example below. And this is the code: // Final_Project.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> #include <string> #include <iomanip> using namespace std; // //CLASS DECLARATION SECTION // class CEmployee { public: void ImplementCalculations(string EmployeeName, double hours, double wage); void DisplayEmployInformation(void); void Addsomethingup (CEmployee, CEmployee, CEmployee); string EmployeeName ; int hours ; int overtime_hours ; int iTotal_hours ; int iTotal_OvertimeHours ; float wage ; float basepay ; float overtime_pay ; float overtime_extra ; float iTotal_salaries ; float iIndividualSalary ; }; int main() { system("cls"); cout << "Welcome to the Employee Pay Center"; /* Use this section to define your objects. You will have one object per employee. You have only three employees. The format is your class name and your object name. */ std::cout << "Please enter Employee's Name: "; std::cin >> EmployeeName; std::cout << "Please enter Total Hours for (EmployeeName): "; std::cin >> hours; std::cout << "Please enter Base Pay for(EmployeeName): "; std::cin >> basepay; /* Here you will prompt for the first employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Example of Prompts Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the second employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the third employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will implement a function call to implement the employ calcuations for each object defined above. You will do this for each of the three employees or objects. The format for this step is the following: [(object name.function name(objectname.name, objectname.hours, objectname.wage)] ; */ /* This section you will send all three objects to a function that will add up the the following information: - Total Employee Salaries - Total Employee Hours - Total Overtime Hours The format for this function is the following: - Define a new object. - Implement function call [objectname.functionname(object name 1, object name 2, object name 3)] /* } //End of Main Function void CEmployee::ImplementCalculations (string EmployeeName, double hours, double wage){ //Initialize overtime variables overtime_hours=0; overtime_pay=0; overtime_extra=0; if (hours > 40) { /* This section is for the basic calculations for calculating overtime pay. - base pay = 40 hours times the hourly wage - overtime hours = hours worked – 40 - overtime pay = hourly wage * 1.5 - overtime extra pay over 40 = overtime hours * overtime pay - salary = overtime money over 40 hours + your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // if (hours > 40) else { /* Here you are going to calculate the hours less than 40 hours. - Your base pay is = your hours worked times your wage - Salary = your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // End of the else } //End of Primary Function void CEmployee::DisplayEmployInformation(); { // This function displays all the employee output information. /* This is your cout statements to display the employee information: Employee Name ............. = Base Pay .................. = Hours in Overtime ......... = Overtime Pay Amount........ = Total Pay ................. = */ } // END OF Display Employee Information void CEmployee::Addsomethingup (CEmployee Employ1, CEmployee Employ2) { // Adds two objects of class Employee passed as // function arguments and saves them as the calling object's data member values. /* Add the total hours for objects 1, 2, and 3. Add the salaries for each object. Add the total overtime hours. */ /* Then display the information below. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% EMPLOYEE SUMMARY DATA%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% Total Employee Salaries ..... = 576.43 %%%% Total Employee Hours ........ = 108 %%%% Total Overtime Hours......... = 5 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% */ } // End of function

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Silverlight 4 + WCF RIA - Data Service Design Best Practices

- by Chadd Nervig

Hey all. I realize this is a rather long question, but I'd really appreciate any help from anyone experienced with RIA services. Thanks! I'm working on a Silverlight 4 app that views data from the server. I'm relatively inexperienced with RIA Services, so have been working through the tasks of getting the data I need down to the client, but every new piece I add to the puzzle seems to be more and more problematic. I feel like I'm missing some basic concepts here, and it seems like I'm just 'hacking' pieces on, in time-consuming ways, each one breaking the previous ones as I try to add them. I'd love to get the feedback of developers experienced with RIA services, to figure out the intended way to do what I'm trying to do. Let me lay out what I'm trying to do: First, the data. The source of this data is a variety of sources, primarily created by a shared library which reads data from our database, and exposes it as POCOs (Plain Old CLR Objects). I'm creating my own POCOs to represent the different types of data I need to pass between server and client. DataA - This app is for viewing a certain type of data, lets call DataA, in near-realtime. Every 3 minutes, the client should pull data down from the server, of all the new DataA since the last time it requested data. DataB - Users can view the DataA objects in the app, and may select one of them from the list, which displays additional details about that DataA. I'm bringing these extra details down from the server as DataB. DataC - One of the things that DataB contains is a history of a couple important values over time. I'm calling each data point of this history a DataC object, and each DataB object contains many DataCs. The Data Model - On the server side, I have a single DomainService: [EnableClientAccess] public class MyDomainService : DomainService { public IEnumerable<DataA> GetDataA(DateTime? startDate) { /*Pieces together the DataAs that have been created since startDate, and returns them*/ } public DataB GetDataB(int dataAID) { /*Looks up the extended info for that dataAID, constructs a new DataB with that DataA's data, plus the extended info (with multiple DataCs in a List<DataC> property on the DataB), and returns it*/ } //Not exactly sure why these are here, but I think it //wouldn't compile without them for some reason? The data //is entirely read-only, so I don't need to update. public void UpdateDataA(DataA dataA) { throw new NotSupportedException(); } public void UpdateDataB(DataB dataB) { throw new NotSupportedException(); } } The classes for DataA/B/C look like this: [KnownType(typeof(DataB))] public partial class DataA { [Key] [DataMember] public int DataAID { get; set; } [DataMember] public decimal MyDecimalA { get; set; } [DataMember] public string MyStringA { get; set; } [DataMember] public DataTime MyDateTimeA { get; set; } } public partial class DataB : DataA { [Key] [DataMember] public int DataAID { get; set; } [DataMember] public decimal MyDecimalB { get; set; } [DataMember] public string MyStringB { get; set; } [Include] //I don't know which of these, if any, I need? [Composition] [Association("DataAToC","DataAID","DataAID")] public List<DataC> DataCs { get; set; } } public partial class DataC { [Key] [DataMember] public int DataAID { get; set; } [Key] [DataMember] public DateTime Timestamp { get; set; } [DataMember] public decimal MyHistoricDecimal { get; set; } } I guess a big question I have here is... Should I be using Entities instead of POCOs? Are my classes constructed correctly to be able to pass the data down correctly? Should I be using Invoke methods instead of Query (Get) methods on the DomainService? On the client side, I'm having a number of issues. Surprisingly, one of my biggest ones has been threading. I didn't expect there to be so many threading issues with MyDomainContext. What I've learned is that you only seem to be able to create MyDomainContextObjects on the UI thread, all of the queries you can make are done asynchronously only, and that if you try to fake doing it synchronously by blocking the calling thread until the LoadOperation finishes, you have to do so on a background thread, since it uses the UI thread to make the query. So here's what I've got so far. The app should display a stream of the DataA objects, spreading each 3min chunk of them over the next 3min (so they end up displayed 3min after the occurred, looking like a continuous stream, but only have to be downloaded in 3min bursts). To do this, the main form initializes, creates a private MyDomainContext, and starts up a background worker, which continuously loops in a while(true). On each loop, it checks if it has any DataAs left over to display. If so, it displays that Data, and Thread.Sleep()s until the next DataA is scheduled to be displayed. If it's out of data, it queries for more, using the following methods: public DataA[] GetDataAs(DateTime? startDate) { _loadOperationGetDataACompletion = new AutoResetEvent(false); LoadOperation<DataA> loadOperationGetDataA = null; loadOperationGetDataA = _context.Load(_context.GetDataAQuery(startDate), System.ServiceModel.DomainServices.Client.LoadBehavior.RefreshCurrent, false); loadOperationGetDataA.Completed += new EventHandler(loadOperationGetDataA_Completed); _loadOperationGetDataACompletion.WaitOne(); List<DataA> dataAs = new List<DataA>(); foreach (var dataA in loadOperationGetDataA.Entities) dataAs.Add(dataA); return dataAs.ToArray(); } private static AutoResetEvent _loadOperationGetDataACompletion; private static void loadOperationGetDataA_Completed(object sender, EventArgs e) { _loadOperationGetDataACompletion.Set(); } Seems kind of clunky trying to force it into being synchronous, but since this already is on a background thread, I think this is OK? So far, everything actually works, as much of a hack as it seems like it may be. It's important to note that if I try to run that code on the UI thread, it locks, because it waits on the WaitOne() forever, locking the thread, so it can't make the Load request to the server. So once the data is displayed, users can click on one as it goes by to fill a details pane with the full DataB data about that object. To do that, I have the the details pane user control subscribing to a selection event I have setup, which gets fired when the selection changes (on the UI thread). I use a similar technique there, to get the DataB object: void SelectionService_SelectedDataAChanged(object sender, EventArgs e) { DataA dataA = /*Get the selected DataA*/; MyDomainContext context = new MyDomainContext(); var loadOperationGetDataB = context.Load(context.GetDataBQuery(dataA.DataAID), System.ServiceModel.DomainServices.Client.LoadBehavior.RefreshCurrent, false); loadOperationGetDataB.Completed += new EventHandler(loadOperationGetDataB_Completed); } private void loadOperationGetDataB_Completed(object sender, EventArgs e) { this.DataContext = ((LoadOperation<DataB>)sender).Entities.SingleOrDefault(); } Again, it seems kinda hacky, but it works... except on the DataB that it loads, the DataCs list is empty. I've tried all kinds of things there, and I don't see what I'm doing wrong to allow the DataCs to come down with the DataB. I'm about ready to make a 3rd query for the DataCs, but that's screaming even more hackiness to me. It really feels like I'm fighting against the grain here, like I'm doing this in an entirely unintended way. If anyone could offer any assistance, and point out what I'm doing wrong here, I'd very much appreciate it! Thanks!

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DirectShow: Video-Preview and Image (with working code)

- by xsl

Questions / Issues If someone can recommend me a good free hosting site I can provide the whole project file. As mentioned in the text below the TakePicture() method is not working properly on the HTC HD 2 device. It would be nice if someone could look at the code below and tell me if it is right or wrong what I'm doing. Introduction I recently asked a question about displaying a video preview, taking camera image and rotating a video stream with DirectShow. The tricky thing about the topic is, that it's very hard to find good examples and the documentation and the framework itself is very hard to understand for someone who is new to windows programming and C++ in general. Nevertheless I managed to create a class that implements most of this features and probably works with most mobile devices. Probably because the DirectShow implementation depends a lot on the device itself. I could only test it with the HTC HD and HTC HD2, which are known as quite incompatible. HTC HD Working: Video preview, writing photo to file Not working: Set video resolution (CRASH), set photo resolution (LOW quality) HTC HD 2 Working: Set video resolution, set photo resolution Problematic: Video Preview rotated Not working: Writing photo to file To make it easier for others by providing a working example, I decided to share everything I have got so far below. I removed all of the error handling for the sake of simplicity. As far as documentation goes, I can recommend you to read the MSDN documentation, after that the code below is pretty straight forward. void Camera::Init() { CreateComObjects(); _captureGraphBuilder->SetFiltergraph(_filterGraph); InitializeVideoFilter(); InitializeStillImageFilter(); } Dipslay a video preview (working with any tested handheld): void Camera::DisplayVideoPreview(HWND windowHandle) { IVideoWindow *_vidWin; _filterGraph->QueryInterface(IID_IMediaControl,(void **) &_mediaControl); _filterGraph->QueryInterface(IID_IVideoWindow, (void **) &_vidWin); _videoCaptureFilter->QueryInterface(IID_IAMVideoControl, (void**) &_videoControl); _captureGraphBuilder->RenderStream(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, _videoCaptureFilter, NULL, NULL); CRect rect; long width, height; GetClientRect(windowHandle, &rect); _vidWin->put_Owner((OAHWND)windowHandle); _vidWin->put_WindowStyle(WS_CHILD | WS_CLIPSIBLINGS); _vidWin->get_Width(&width); _vidWin->get_Height(&height); height = rect.Height(); _vidWin->put_Height(height); _vidWin->put_Width(rect.Width()); _vidWin->SetWindowPosition(0,0, rect.Width(), height); _mediaControl->Run(); } HTC HD2: If set SetPhotoResolution() is called FindPin will return E_FAIL. If not, it will create a file full of null bytes. HTC HD: Works void Camera::TakePicture(WCHAR *fileName) { CComPtr<IFileSinkFilter> fileSink; CComPtr<IPin> stillPin; CComPtr<IUnknown> unknownCaptureFilter; CComPtr<IAMVideoControl> videoControl; _imageSinkFilter.QueryInterface(&fileSink); fileSink->SetFileName(fileName, NULL); _videoCaptureFilter.QueryInterface(&unknownCaptureFilter); _captureGraphBuilder->FindPin(unknownCaptureFilter, PINDIR_OUTPUT, &PIN_CATEGORY_STILL, &MEDIATYPE_Video, FALSE, 0, &stillPin); _videoCaptureFilter.QueryInterface(&videoControl); videoControl->SetMode(stillPin, VideoControlFlag_Trigger); } Set resolution: Works great on HTC HD2. HTC HD won't allow SetVideoResolution() and only offers one low resolution photo resolution: void Camera::SetVideoResolution(int width, int height) { SetResolution(true, width, height); } void Camera::SetPhotoResolution(int width, int height) { SetResolution(false, width, height); } void Camera::SetResolution(bool video, int width, int height) { IAMStreamConfig *config; config = NULL; if (video) { _captureGraphBuilder->FindInterface(&PIN_CATEGORY_PREVIEW, &MEDIATYPE_Video, _videoCaptureFilter, IID_IAMStreamConfig, (void**) &config); } else { _captureGraphBuilder->FindInterface(&PIN_CATEGORY_STILL, &MEDIATYPE_Video, _videoCaptureFilter, IID_IAMStreamConfig, (void**) &config); } int resolutions, size; VIDEO_STREAM_CONFIG_CAPS caps; config->GetNumberOfCapabilities(&resolutions, &size); for (int i = 0; i < resolutions; i++) { AM_MEDIA_TYPE *mediaType; if (config->GetStreamCaps(i, &mediaType, reinterpret_cast<BYTE*>(&caps)) == S_OK ) { int maxWidth = caps.MaxOutputSize.cx; int maxHeigth = caps.MaxOutputSize.cy; if(maxWidth == width && maxHeigth == height) { VIDEOINFOHEADER *info = reinterpret_cast<VIDEOINFOHEADER*>(mediaType->pbFormat); info->bmiHeader.biWidth = maxWidth; info->bmiHeader.biHeight = maxHeigth; info->bmiHeader.biSizeImage = DIBSIZE(info->bmiHeader); config->SetFormat(mediaType); DeleteMediaType(mediaType); break; } DeleteMediaType(mediaType); } } } Other methods used to build the filter graph and create the COM objects: void Camera::CreateComObjects() { CoInitialize(NULL); CoCreateInstance(CLSID_CaptureGraphBuilder, NULL, CLSCTX_INPROC_SERVER, IID_ICaptureGraphBuilder2, (void **) &_captureGraphBuilder); CoCreateInstance(CLSID_FilterGraph, NULL, CLSCTX_INPROC_SERVER, IID_IGraphBuilder, (void **) &_filterGraph); CoCreateInstance(CLSID_VideoCapture, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void**) &_videoCaptureFilter); CoCreateInstance(CLSID_IMGSinkFilter, NULL, CLSCTX_INPROC, IID_IBaseFilter, (void**) &_imageSinkFilter); } void Camera::InitializeVideoFilter() { _videoCaptureFilter->QueryInterface(&_propertyBag); wchar_t deviceName[MAX_PATH] = L"\0"; GetDeviceName(deviceName); CComVariant comName = deviceName; CPropertyBag propertyBag; propertyBag.Write(L"VCapName", &comName); _propertyBag->Load(&propertyBag, NULL); _filterGraph->AddFilter(_videoCaptureFilter, L"Video Capture Filter Source"); } void Camera::InitializeStillImageFilter() { _filterGraph->AddFilter(_imageSinkFilter, L"Still image filter"); _captureGraphBuilder->RenderStream(&PIN_CATEGORY_STILL, &MEDIATYPE_Video, _videoCaptureFilter, NULL, _imageSinkFilter); } void Camera::GetDeviceName(WCHAR *deviceName) { HRESULT hr = S_OK; HANDLE handle = NULL; DEVMGR_DEVICE_INFORMATION di; GUID guidCamera = { 0xCB998A05, 0x122C, 0x4166, 0x84, 0x6A, 0x93, 0x3E, 0x4D, 0x7E, 0x3C, 0x86 }; di.dwSize = sizeof(di); handle = FindFirstDevice(DeviceSearchByGuid, &guidCamera, &di); StringCchCopy(deviceName, MAX_PATH, di.szLegacyName); } Full header file: #ifndef __CAMERA_H__ #define __CAMERA_H__ class Camera { public: void Init(); void DisplayVideoPreview(HWND windowHandle); void TakePicture(WCHAR *fileName); void SetVideoResolution(int width, int height); void SetPhotoResolution(int width, int height); private: CComPtr<ICaptureGraphBuilder2> _captureGraphBuilder; CComPtr<IGraphBuilder> _filterGraph; CComPtr<IBaseFilter> _videoCaptureFilter; CComPtr<IPersistPropertyBag> _propertyBag; CComPtr<IMediaControl> _mediaControl; CComPtr<IAMVideoControl> _videoControl; CComPtr<IBaseFilter> _imageSinkFilter; void GetDeviceName(WCHAR *deviceName); void InitializeVideoFilter(); void InitializeStillImageFilter(); void CreateComObjects(); void SetResolution(bool video, int width, int height); }; #endif

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Dealing with external processes

- by Jesse Aldridge

I've been working on a gui app that needs to manage external processes. Working with external processes leads to a lot of issues that can make a programmer's life difficult. I feel like maintenence on this app is taking an unacceptably long time. I've been trying to list the things that make working with external processes difficult so that I can come up with ways of mitigating the pain. This kind of turned into a rant which I thought I'd post here in order to get some feedback and to provide some guidance to anybody thinking about sailing into these very murky waters. Here's what I've got so far: Output from the child can get mixed up with output from the parent. This can make both outputs misleading and hard to read. It can be hard to tell what came from where. It becomes harder to figure out what's going on when things are asynchronous. Here's a contrived example: import textwrap, os, time from subprocess import Popen test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) proc = Popen('python -B "%s"' % test_path) for i in range(3): print 'Hello %i' % i time.sleep(1) os.remove(test_path) I guess I could have the child process write its output to a file. But it can be annoying to have to open up a file every time I want to see the result of a print statement. If I have code for the child process I could add a label, something like print 'child: Hello %i', but it can be annoying to do that for every print. And it adds some noise to the output. And of course I can't do it if I don't have access to the code. I could manually manage the process output. But then you open up a huge can of worms with threads and polling and stuff like that. A simple solution is to treat processes like synchronous functions, that is, no further code executes until the process completes. In other words, make the process block. But that doesn't work if you're building a gui app. Which brings me to the next problem... Blocking processes cause the gui to become unresponsive. import textwrap, sys, os from subprocess import Popen from PyQt4.QtGui import * from PyQt4.QtCore import * test_path = 'test_file.py' with open(test_path, 'w') as file: file.write(textwrap.dedent(''' import time for i in range(3): print 'Hello %i' % i time.sleep(1)''')) app = QApplication(sys.argv) button = QPushButton('Launch process') def launch_proc(): # Can't move the window until process completes proc = Popen('python -B "%s"' % test_path) proc.communicate() button.connect(button, SIGNAL('clicked()'), launch_proc) button.show() app.exec_() os.remove(test_path) Qt provides a process wrapper of its own called QProcess which can help with this. You can connect functions to signals to capture output relatively easily. This is what I'm currently using. But I'm finding that all these signals behave suspiciously like goto statements and can lead to spaghetti code. I think I want to get sort-of blocking behavior by having the 'finished' signal from QProcess call a function containing all the code that comes after the process call. I think that should work but I'm still a bit fuzzy on the details... Stack traces get interrupted when you go from the child process back to the parent process. If a normal function screws up, you get a nice complete stack trace with filenames and line numbers. If a subprocess screws up, you'll be lucky if you get any output at all. You end up having to do a lot more detective work everytime something goes wrong. Speaking of which, output has a way of disappearing when dealing external processes. Like if you run something via the windows 'cmd' command, the console will pop up, execute the code, and then disappear before you have a chance to see the output. You have to pass the /k flag to make it stick around. Similar issues seem to crop up all the time. I suppose both problems 3 and 4 have the same root cause: no exception handling. Exception handling is meant to be used with functions, it doesn't work with processes. Maybe there's some way to get something like exception handling for processes? I guess that's what stderr is for? But dealing with two different streams can be annoying in itself. Maybe I should look into this more... Processes can hang and stick around in the background without you realizing it. So you end up yelling at your computer cuz it's going so slow until you finally bring up your task manager and see 30 instances of the same process hanging out in the background. Also, hanging background processes can interefere with other instances of the process in various fun ways, such as causing permissions errors by holding a handle to a file or someting like that. It seems like an easy solution to this would be to have the parent process kill the child process on exit if the child process didn't close itself. But if the parent process crashes, cleanup code might not get called and the child can be left hanging. Also, if the parent waits for the child to complete, and the child is in an infinite loop or something, you can end up with two hanging processes. This problem can tie in to problem 2 for extra fun, causing your gui to stop responding entirely and force you to kill everything with the task manager. F***ing quotes Parameters often need to be passed to processes. This is a headache in itself. Especially if you're dealing with file paths. Say... 'C:/My Documents/whatever/'. If you don't have quotes, the string will often be split at the space and interpreted as two arguments. If you need nested quotes you can use ' and ". But if you need to use more than two layers of quotes, you have to do some nasty escaping, for example: "cmd /k 'python \'path 1\' \'path 2\''". A good solution to this problem is passing parameters as a list rather than as a single string. Subprocess allows you to do this. Can't easily return data from a subprocess. You can use stdout of course. But what if you want to throw a print in there for debugging purposes? That's gonna screw up the parent if it's expecting output formatted a certain way. In functions you can print one string and return another and everything works just fine. Obscure command-line flags and a crappy terminal based help system. These are problems I often run into when using os level apps. Like the /k flag I mentioned, for holding a cmd window open, who's idea was that? Unix apps don't tend to be much friendlier in this regard. Hopefully you can use google or StackOverflow to find the answer you need. But if not, you've got a lot of boring reading and frusterating trial and error to do. External factors. This one's kind of fuzzy. But when you leave the relatively sheltered harbor of your own scripts to deal with external processes you find yourself having to deal with the "outside world" to a much greater extent. And that's a scary place. All sorts of things can go wrong. Just to give a random example: the cwd in which a process is run can modify it's behavior. There are probably other issues, but those are the ones I've written down so far. Any other snags you'd like to add? Any suggestions for dealing with these problems?

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Why can't I assign a scalar value to a class using shorthand, but instead declare it first, then set

- by ~delan-azabani

I am writing a UTF-8 library for C++ as an exercise as this is my first real-world C++ code. So far, I've implemented concatenation, character indexing, parsing and encoding UTF-8 in a class called "ustring". It looks like it's working, but two (seemingly equivalent) ways of declaring a new ustring behave differently. The first way: ustring a; a = "test"; works, and the overloaded "=" operator parses the string into the class (which stores the Unicode strings as an dynamically allocated int pointer). However, the following does not work: ustring a = "test"; because I get the following error: test.cpp:4: error: conversion from ‘const char [5]’ to non-scalar type ‘ustring’ requested Is there a way to workaround this error? It probably is a problem with my code, though. The following is what I've written so far for the library: #include <cstdlib> #include <cstring> class ustring { int * values; long len; public: long length() { return len; } ustring * operator=(ustring input) { len = input.len; values = (int *) malloc(sizeof(int) * len); for (long i = 0; i < len; i++) values[i] = input.values[i]; return this; } ustring * operator=(char input[]) { len = sizeof(input); values = (int *) malloc(0); long s = 0; // s = number of parsed chars int a, b, c, d, contNeed = 0, cont = 0; for (long i = 0; i < sizeof(input); i++) if (input[i] < 0x80) { // ASCII, direct copy (00-7f) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = input[i]; } else if (input[i] < 0xc0) { // this is a continuation (80-bf) if (cont == contNeed) { // no need for continuation, use U+fffd values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } cont = cont + 1; values[s - 1] = values[s - 1] | ((input[i] & 0x3f) << ((contNeed - cont) * 6)); if (cont == contNeed) cont = contNeed = 0; } else if (input[i] < 0xc2) { // invalid byte, use U+fffd (c0-c1) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } else if (input[i] < 0xe0) { // start of 2-byte sequence (c2-df) contNeed = 1; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x1f) << 6; } else if (input[i] < 0xf0) { // start of 3-byte sequence (e0-ef) contNeed = 2; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x0f) << 12; } else if (input[i] < 0xf5) { // start of 4-byte sequence (f0-f4) contNeed = 3; values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = (input[i] & 0x07) << 18; } else { // restricted or invalid (f5-ff) values = (int *) realloc(values, sizeof(int) * ++s); values[s - 1] = 0xfffd; } return this; } ustring operator+(ustring input) { ustring result; result.len = len + input.len; result.values = (int *) malloc(sizeof(int) * result.len); for (long i = 0; i < len; i++) result.values[i] = values[i]; for (long i = 0; i < input.len; i++) result.values[i + len] = input.values[i]; return result; } ustring operator[](long index) { ustring result; result.len = 1; result.values = (int *) malloc(sizeof(int)); result.values[0] = values[index]; return result; } char * encode() { char * r = (char *) malloc(0); long s = 0; for (long i = 0; i < len; i++) { if (values[i] < 0x80) r = (char *) realloc(r, s + 1), r[s + 0] = char(values[i]), s += 1; else if (values[i] < 0x800) r = (char *) realloc(r, s + 2), r[s + 0] = char(values[i] >> 6 | 0x60), r[s + 1] = char(values[i] & 0x3f | 0x80), s += 2; else if (values[i] < 0x10000) r = (char *) realloc(r, s + 3), r[s + 0] = char(values[i] >> 12 | 0xe0), r[s + 1] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 2] = char(values[i] & 0x3f | 0x80), s += 3; else r = (char *) realloc(r, s + 4), r[s + 0] = char(values[i] >> 18 | 0xf0), r[s + 1] = char(values[i] >> 12 & 0x3f | 0x80), r[s + 2] = char(values[i] >> 6 & 0x3f | 0x80), r[s + 3] = char(values[i] & 0x3f | 0x80), s += 4; } return r; } };

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Bizarre Son of Suckerfish ie6/ie7 problem - 2 letters from right-most dropdown menu also appearing o

- by Kevin Burke

I'm interning for an NGO in India and trying to fix their website, including updating their menu so it's not the last item on the page to load, and it's centered on the screen. Everything works well enough but when I try out my new menu in IE6, I get this weird error where the content below the menu is padded an extra 30px or so and the material in the right-most drop down appears on the far left of the screen, always visible. When I drop down the rightmost link ("Publications") the content appears both in the correct location and in the same spot on the far left of the screen, and changes color when I hover as well. It's tough to describe, so it would probably be best if you took a look: visit http://sevamandir.org/a30/aboutus.htm in your IE6/IE7 browser to see for yourself. I really appreciate your help. Also I'm using a 1000px wide monitor, if there's more hijinks going on outside that space I'd like to know about that too. I took a look at the problem again and it's even weirder than I thought. Only two letters of the bottom-most drop down menu item are shown, no matter how many items are in the left-most drop down menu. When I delete the left-most drop down menu, the bottom item from the next left-most item shows up in the same space. The padding between the menu and the content is always the same. When I hover over the real menu item, the two letters on the left hand side change color to match the hover color. Unfortunately many people that visit our website are using old browsers so IE6 support is pretty crucial, this problem is really weird though, and I would appreciate some help. I uploaded a file with the entire style.css sheet in the and HTML code below, at http://sevamandir.org/a30/aboutus.htm. Here's the relevant code: in the html head: <script> sfHover = function() { var sfEls = document.getElementById("nav").getElementsByTagName("LI"); for (var i=0; i<sfEls.length; i++) { sfEls[i].onmouseover=function() { this.className+=" sfhover"; } sfEls[i].onmouseout=function() { this.className=this.className.replace(new RegExp(" sfhover\\b"), ""); } } } if (window.attachEvent) window.attachEvent("onload", sfHover); </script> text surrounding the menu - the menu is simply <ul id="nav"><li></li></ul> etc.  <div style="float:left; height:27px; width:520px; margin:0px; font:16px Arial, Helvetica, sans-serif; font-weight:bold; color:#769841;"> Transforming lives through democratic & participatory development </div> <?php include("menu.php"); ?> </div>  <div id="maincontent"> Relevant menu CSS: #nav, #nav ul { font:bold 11px Verdana, sans-serif; float: left; width: 980px; list-style: none; line-height: 1; background: white; font-weight: bold; padding: 0; border: solid #769841; border-width: 0; margin: 0 0 1em 0; } #nav a { display: block; width: 140px; /*this is the total width of the upper menu*/ w\idth: 120px; /*this is the width less horizontal padding */ padding: 5px 10px 5px 10px; /*horiz padding is the 2nd & 4th items here - goes Top Right Bottom Left */ color: #ffffff; background:#b6791e; text-decoration: none; } #nav a.daddy { background: url(rightarrow2.gif) center right no-repeat; } #nav li { float: left; padding: 0; width: 140px; /*this needs to be updated to match top #nav a */ background:#b6791e; } #nav li:hover, #nav li a:hover, #nav li:hover a { background:#769841; } #nav li:hover li a { background:#ffffff; color:#769841; } #nav li ul { position: absolute; left: -999em; height: auto; width: 14.4em; w\idth: 13.9em; font-weight: bold; border-width: 0.25em; /*green border around dropdown menu*/ margin: 0; } #nav li ul a { background:#ffffff; color:#769841; } #nav li li { padding-right: 1em; width: 13em; background:#ffffff; } #nav li ul a { width: 13em; w\idth: 9em; } #nav li ul ul { margin: -1.75em 0 0 14em; } #nav li:hover ul ul, #nav li:hover ul ul ul, #nav li.sfhover ul ul, #nav li.sfhover ul ul ul { left: -999em; } #nav li:hover ul, #nav li li:hover ul, #nav li li li:hover ul, #nav li.sfhover ul, #nav li li.sfhover ul, #nav li li li.sfhover ul { left: auto; } #nav li:hover, #nav li.sfhover, { background: #769841; color:#ffe400; } #nav li a:hover, #nav li li a:hover, #nav li:hover li:hover, #nav li.sfhover a:hover { background: #769841; color:#ffe400; }

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I need help on my C++ assignment using Microsoft Visual C++

- by krayzwytie

Ok, so I don't want you to do my homework for me, but I'm a little lost with this final assignment and need all the help I can get. Learning about programming is tough enough, but doing it online is next to impossible for me... Now, to get to the program, I am going to paste what I have so far. This includes mostly //comments and what I have written so far. If you can help me figure out where all the errors are and how to complete the assignment, I will really appreciate it. Like I said, I don't want you to do my homework for me (it's my final), but any constructive criticism is welcome. This is my final assignment for this class and it is due tomorrow (Sunday before midnight, Arizona time). This is the assignment: Examine the following situation: Your company, Datamax, Inc., is in the process of automating its payroll systems. Your manager has asked you to create a program that calculates overtime pay for all employees. Your program must take into account the employee’s salary, total hours worked, and hours worked more than 40 in a week, and then provide an output that is useful and easily understood by company management. Compile your program utilizing the following background information and the code outline in Appendix D (included in the code section). Submit your project as an attachment including the code and the output. Company Background: Three employees: Mark, John, and Mary The end user needs to be prompted for three specific pieces of input—name, hours worked, and hourly wage. Calculate overtime if input is greater than 40 hours per week. Provide six test plans to verify the logic within the program. Plan 1 must display the proper information for employee #1 with overtime pay. Plan 2 must display the proper information for employee #1 with no overtime pay. Plans 3-6 are duplicates of plan 1 and 2 but for the other employees. Program Requirements: Define a base class to use for the entire program. The class holds the function calls and the variables related to the overtime pay calculations. Define one object per employee. Note there will be three employees. Your program must take the objects created and implement calculations based on total salaries, total hours, and the total number of overtime hours. See the Employee Summary Data section of the sample output. Logic Steps to Complete Your Program: Define your base class. Define your objects from your base class. Prompt for user input, updating your object classes for all three users. Implement your overtime pay calculations. Display overtime or regular time pay calculations. See the sample output below. Implement object calculations by summarizing your employee objects and display the summary information in the example below. And this is the code: // Final_Project.cpp : Defines the entry point for the console application. // #include "stdafx.h" #include <iostream> #include <string> #include <iomanip> using namespace std; // //CLASS DECLARATION SECTION // class CEmployee { public: void ImplementCalculations(string EmployeeName, double hours, double wage); void DisplayEmployInformation(void); void Addsomethingup (CEmployee, CEmployee, CEmployee); string EmployeeName ; int hours ; int overtime_hours ; int iTotal_hours ; int iTotal_OvertimeHours ; float wage ; float basepay ; float overtime_pay ; float overtime_extra ; float iTotal_salaries ; float iIndividualSalary ; }; int main() { system("cls"); cout << "Welcome to the Employee Pay Center"; /* Use this section to define your objects. You will have one object per employee. You have only three employees. The format is your class name and your object name. */ std::cout << "Please enter Employee's Name: "; std::cin >> EmployeeName; std::cout << "Please enter Total Hours for (EmployeeName): "; std::cin >> hours; std::cout << "Please enter Base Pay for(EmployeeName): "; std::cin >> basepay; /* Here you will prompt for the first employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Example of Prompts Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the second employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will prompt for the third employee’s information. Prompt the employee name, hours worked, and the hourly wage. For each piece of information, you will update the appropriate class member defined above. Enter the employee name = Enter the hours worked = Enter his or her hourly wage = */ /* Here you will implement a function call to implement the employ calcuations for each object defined above. You will do this for each of the three employees or objects. The format for this step is the following: [(object name.function name(objectname.name, objectname.hours, objectname.wage)] ; */ /* This section you will send all three objects to a function that will add up the the following information: - Total Employee Salaries - Total Employee Hours - Total Overtime Hours The format for this function is the following: - Define a new object. - Implement function call [objectname.functionname(object name 1, object name 2, object name 3)] /* } //End of Main Function void CEmployee::ImplementCalculations (string EmployeeName, double hours, double wage){ //Initialize overtime variables overtime_hours=0; overtime_pay=0; overtime_extra=0; if (hours > 40) { /* This section is for the basic calculations for calculating overtime pay. - base pay = 40 hours times the hourly wage - overtime hours = hours worked – 40 - overtime pay = hourly wage * 1.5 - overtime extra pay over 40 = overtime hours * overtime pay - salary = overtime money over 40 hours + your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // if (hours > 40) else { /* Here you are going to calculate the hours less than 40 hours. - Your base pay is = your hours worked times your wage - Salary = your base pay */ /* Implement function call to output the employee information. Function is defined below. */ } // End of the else } //End of Primary Function void CEmployee::DisplayEmployInformation(); { // This function displays all the employee output information. /* This is your cout statements to display the employee information: Employee Name ............. = Base Pay .................. = Hours in Overtime ......... = Overtime Pay Amount........ = Total Pay ................. = */ } // END OF Display Employee Information void CEmployee::Addsomethingup (CEmployee Employ1, CEmployee Employ2) { // Adds two objects of class Employee passed as // function arguments and saves them as the calling object's data member values. /* Add the total hours for objects 1, 2, and 3. Add the salaries for each object. Add the total overtime hours. */ /* Then display the information below. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% EMPLOYEE SUMMARY DATA%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%% Total Employee Salaries ..... = 576.43 %%%% Total Employee Hours ........ = 108 %%%% Total Overtime Hours......... = 5 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% */ } // End of function

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Java MVC project - either I can't update the drawing, or I can't see it

- by user1881164

I've got a project based around the Model-View-Controller paradigm, and I've been having a lot of trouble with getting it to work properly. The program has 4 panels, which are supposed to allow me to modify an oval drawn on the screen in various ways. These seem to work fine, and after considerable trouble I was able to get them to display in the JFrame which holds the whole shebang. I've managed to get them to display by breaking away from the provided instructions, but when I do that, I can't seem to get the oval to update. However, if I follow the directions to the letter, I only ever see an empty frame. The project had pretty specific directions, which I followed up to a point, but some of the documentation was unclear. I think what I'm missing must be something simple, since nothing is jumping out at me as not making sense. I have to admit though that my Java experience is limited and my experience with GUI design/paradigms is even more so. Anyway, I've been searching the web and this site extensively trying to figure out what's wrong, but this is a somewhat specific example and honestly I just don't know enough about this to generalize any of the answers I've found online and figure out what's missing. I've been poring over this code for far too long now so I'm really hoping someone can help me out. public class Model { private Controller controller; private View view; private MvcFrame mvcFrame; private int radius = 44; private Color color = Color.BLUE; private boolean solid = true; //bunch of mutators and accessors for the above variables public Model() { controller = new Controller(this); view = new View(this); mvcFrame = new MvcFrame(this); } } Here's the model class. This seems to be fairly simple. I think my understanding of what's going on here is solid, and nothing seems to be wrong. Included mostly for context. public class Controller extends JPanel{ private Model model; public Controller(Model model) { this.model = model; setBorder(BorderFactory.createLineBorder(Color.GREEN)); setLayout(new GridLayout(4,1)); add(new RadiusPanel(model)); add(new ColorPanel(model)); add(new SolidPanel(model)); add(new TitlePanel(model)); } } This is the Controller class. As far as I can tell, the setBorder, setLayout, and series of adds do nothing here. I had them commented out, but this is the way that the instructions told me to do things, so either there's a mistake there or something about my setup is wrong. However, when I did it this way, I would get an empty window (JFrame) but none of the panels would show up in it. What I did to fix this is put those add functions in the mvcFrame class: public class MvcFrame extends JFrame { private Model model; public MvcFrame(Model model){ this.model = model; //setLayout(new GridLayout(4,1)); //add(new RadiusPanel(model)); //add(new ColorPanel(model)); //add(new SolidPanel(model)); //add(new TitlePanel(model)); //add(new View(model)); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); setLocationRelativeTo(null); setSize(800,600); setVisible(true); } } So here's where things kind of started getting weird. The first block of commented out code is the same as what's in the Controller class. The reason I have it commented out is because that was just a lucky guess - it's not supposed to be like that according to the instructions. However, this did work for getting the panels to show up - but at that point I was still tearing my hair out trying to get the oval to display. The other commented line ( add(new View(model)); ) was a different attempt at making things work. In this case, I put those add functions in the View class (see commented out code below). This actually worked to display both the oval and the panels, but that method wouldn't allow me to update the oval. Also, though I just had the oval displaying, I can't seem to figure out what exactly made that happen, and I can't seem to make it come back. public class View extends JPanel{ private Model model; public View(Model model) { this.model = model; //setLayout(new GridLayout(4,1)); //add(new RadiusPanel(model)); //add(new ColorPanel(model)); //add(new SolidPanel(model)); //add(new TitlePanel(model)); repaint(); } @Override protected void paintComponent(Graphics g){ super.paintComponent(g); //center of view panel, in pixels: int xCenter = getWidth()/2; int yCenter = getHeight()/2; int radius = model.getRadius(); int xStart = xCenter - radius; int yStart = yCenter - radius; int xWidth = 2 * radius; int yHeight = 2 * radius; g.setColor(model.getColor()); g.clearRect(0, 0, getWidth(), getHeight()); if (model.isSolid()){ g.fillOval(xStart, yStart, xWidth, yHeight); } else { g.drawOval(xStart, yStart, xWidth, yHeight); } } } Kinda same idea as before - the commented out code is stuff I added to try to get things working, but is not based on the provided directions. In the case where that stuff was uncommented, I had the add(new View(model)); line from the mvcFrame line uncommented as well. The various panel classes (SolidPanel, ColorPanel, etc) simply extend a class called ControlPanel which extends JPanel. These all seem to work as expected, not having much issue with them. There is also a driver which launches the GUI. This also seems to work as expected. The main problem I'm having is that I can't get the oval to show up, and the one time I could make it show up, none of the options for changing it seemed to work. I feel like I'm close but I'm just at a loss for other things to try out at this point. Anyone who can help will have my sincerest gratitude.

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Databinding, using formulas for unusual binding possible?

- by Rattenmann

Edit: added Info for WPF being used I am trying to bind a list of custom objects to a DataGrid. Straight binding seems easy enough, but i need to specify some complex formulas for some extra fields that do not directly show up in my class. Also i want to be able to EDIT the data in the Grid and get updates on related fields. Let me show you an example, because it is really hard to explain. I will simplify it to rooms with items. Each item can be red and blue. My Class looks like this: public class room { public string strRoomName { set; get; } public string strItemname { set; get; } public int intRedItem { set; get; } public int intBlueItem { set; get; } } Now if i use dataTable.ItemSource = myList; i get something like this: nr. | room | name | red | blue 1. living room, ball, 2, 1 2. sleeping room, bunny, 4, 1 3. living room, chair, 3, 2 4. kitchen, ball, 4, 7 5. garage, chair, 1, 4 Now for the complex part i need help with. I want every item to be the same number, red and blue. And because this does not hold true i want to see the "inbalance" per room AND globally like this: nr. | room | name | red | blue | missing | global red | global blue | global missing 1. living room, ball, 2, 1, 1 blue, 6, 7, 1 red 2. sleeping room, bunny, 4, 1, 3 blue, 4, 1, 3 blue 3. living room, chair, 3, 2, 1 blue, 4, 6, 2 red 4. kitchen, ball, 4, 7, 3 red, 6, 7, 1 red 5. garage, chair, 1, 4, 3 red, 4, 6, 2 red As you can see this smeels like excel formulas, i am unsure how to handle this in c# code however. You can also see i need to use data in the same row, but also get data from other rows that match one propertiy (the items name). Also if i change the blue value=1 in line 1 to value=2, i want line 1 to read like this: 1. living room, ball, 2, 2, even, 6, 8, 2 red and of corse line 4 needs to change to: 4. kitchen, ball, 4, 7, 3 red, 6, 8, 2 red As i said, this smells like excel, that's why i am really upset about myself not finding an easy solution. Surely enough c# offers some way to handle this stuff, right? Disclaimer: It is totally possible that i need a complete differend approach, pointing that out ot me is perfectly fine. Be it other ways to handle this, or a better way to structure my class. I am ok with every way to handle this as it is for learning purposes. I am simply doing programms for fun next to my college and just so happen to hit these kinda things that bug me out because i don't find a clean solution. And then i neglect my studies because i want to solve my (unreleated to studys,...) issue. Just can't stand having unsolved coding stuff around, don't judge me! ;-) And big thanks in advance if you have gotten this far in my post. It sure must be confusing with all those reds and blues. Edit: After reading trough your answers and testing my skills to implement your hints, i now have the following code as my class: public class RoomList : ObservableCollection<room> { public RoomList() : base() { Add(new room() { strRoomName = "living room", strItemname = "ball", intRedItem = 2, intBlueItem = 1 }); Add(new room() { strRoomName = "sleeping room", strItemname = "bunny", intRedItem = 4, intBlueItem = 1 }); Add(new room() { strRoomName = "living room", strItemname = "chair", intRedItem = 3, intBlueItem = 2 }); Add(new room() { strRoomName = "kitchen", strItemname = "ball", intRedItem = 4, intBlueItem = 7 }); Add(new room() { strRoomName = "garage", strItemname = "chair", intRedItem = 1, intBlueItem = 4 }); } } //rooms public class room : INotifyPropertyChanged { public string strRoomName { set; get; } public string strItemname { set; get; } public int intRedItem { get { return intRedItem; } set { intRedItem = value; NotifyPropertyChanged("intRedItem", "strMissing"); } } public int intBlueItem { get { return intBlueItem; } set { intBlueItem = value; NotifyPropertyChanged("intBlueItem", "strMissing"); } } public string strMissing { get { int missingCount = intRedItem - intBlueItem; return missingCount == 0 ? "Even" : missingCount.ToString(); } } public event PropertyChangedEventHandler PropertyChanged; public void NotifyPropertyChanged(params string[] propertyNames) { if (PropertyChanged != null) { foreach (string propertyName in propertyNames) { PropertyChanged(this, new PropertyChangedEventArgs(propertyName)); } } } } I got the "missing" field working right away, thanks alot for that tip. It really was as easy as i imagined and will be of great use for future projects. Still two (three maybe....) things i am missing tho. The above code terminates with a "System.StackOverflowException" in the setter of intRedItem and intBlueItem. I fail to see the error, that could be due to being 4:30am here, or my lack of understanding. Second issue: I followed the link to ObservableCollections as you can see from my code above. Yet i am unsure how to actually use that collection. Putting it as DataContent like suggested on that page shows a missing ressource. Adding it as a ressource like listed there crashes my VSExpress designer and leads to the programm not starting. So for now i am still using my old approach of a list like this: listRooms.Add(new room() { strRoomName = "living room", strItemname = "ball", intRedItem = 2, intBlueItem = 1 }); listRooms.Add(new room() { strRoomName = "sleeping room", strItemname = "bunny", intRedItem = 4, intBlueItem = 1 }); listRooms.Add(new room() { strRoomName = "living room", strItemname = "chair", intRedItem = 3, intBlueItem = 2 }); listRooms.Add(new room() { strRoomName = "kitchen", strItemname = "ball", intRedItem = 4, intBlueItem = 7 }); listRooms.Add(new room() { strRoomName = "garage", strItemname = "chair", intRedItem = 1, intBlueItem = 4 }); datagridRooms.ItemsSource = listRooms; And lastly: When testing before adding the notifyevents i tried to implement a proterty that looped trough the other objects, without any luck. The "missingItem" property worked so easy, yet it only tries to access "it's own" properties kind of. I need to access other objects, like "all objects that have the same room value". The idea behind this is that i am trying to calculate a value from other objects without even having those objects yet, at least in my logic. Where is the flaw in my thinking? Those 5 objects are added and created (?) one after another. So if the first tries to set it's "all red balls in my room AND all other rooms" value,.. how could it know about the balls in the kitchen, that get added as 4th object? So far so good tho, got on the right track i think. Just need some sleep first.

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Linked List manipulation, issues retrieving data c++

- by floatfil

I'm trying to implement some functions to manipulate a linked list. The implementation is a template typename T and the class is 'List' which includes a 'head' pointer and also a struct: struct Node { // the node in a linked list T* data; // pointer to actual data, operations in T Node* next; // pointer to a Node }; Since it is a template, and 'T' can be any data, how do I go about checking the data of a list to see if it matches the data input into the function? The function is called 'retrieve' and takes two parameters, the data and a pointer: bool retrieve(T target, T*& ptr); // This is the prototype we need to use for the project "bool retrieve : similar to remove, but not removed from list. If there are duplicates in the list, the first one encountered is retrieved. Second parameter is unreliable if return value is false. E.g., " Employee target("duck", "donald"); success = company1.retrieve(target, oneEmployee); if (success) { cout << "Found in list: " << *oneEmployee << endl; } And the function is called like this: company4.retrieve(emp3, oneEmployee) So that when you cout *oneEmployee, you'll get the data of that pointer (in this case the data is of type Employee). (Also, this is assuming all data types have the apropriate overloaded operators) I hope this makes sense so far, but my issue is in comparing the data in the parameter and the data while going through the list. (The data types that we use all include overloads for equality operators, so oneData == twoData is valid) This is what I have so far: template <typename T> bool List<T>::retrieve(T target , T*& ptr) { List<T>::Node* dummyPtr = head; // point dummy pointer to what the list's head points to for(;;) { if (*dummyPtr->data == target) { // EDIT: it now compiles, but it breaks here and I get an Access Violation error. ptr = dummyPtr->data; // set the parameter pointer to the dummy pointer return true; // return true } else { dummyPtr = dummyPtr->next; // else, move to the next data node } } return false; } Here is the implementation for the Employee class: //-------------------------- constructor ----------------------------------- Employee::Employee(string last, string first, int id, int sal) { idNumber = (id >= 0 && id <= MAXID? id : -1); salary = (sal >= 0 ? sal : -1); lastName = last; firstName = first; } //-------------------------- destructor ------------------------------------ // Needed so that memory for strings is properly deallocated Employee::~Employee() { } //---------------------- copy constructor ----------------------------------- Employee::Employee(const Employee& E) { lastName = E.lastName; firstName = E.firstName; idNumber = E.idNumber; salary = E.salary; } //-------------------------- operator= --------------------------------------- Employee& Employee::operator=(const Employee& E) { if (&E != this) { idNumber = E.idNumber; salary = E.salary; lastName = E.lastName; firstName = E.firstName; } return *this; } //----------------------------- setData ------------------------------------ // set data from file bool Employee::setData(ifstream& inFile) { inFile >> lastName >> firstName >> idNumber >> salary; return idNumber >= 0 && idNumber <= MAXID && salary >= 0; } //------------------------------- < ---------------------------------------- // < defined by value of name bool Employee::operator<(const Employee& E) const { return lastName < E.lastName || (lastName == E.lastName && firstName < E.firstName); } //------------------------------- <= ---------------------------------------- // < defined by value of inamedNumber bool Employee::operator<=(const Employee& E) const { return *this < E || *this == E; } //------------------------------- > ---------------------------------------- // > defined by value of name bool Employee::operator>(const Employee& E) const { return lastName > E.lastName || (lastName == E.lastName && firstName > E.firstName); } //------------------------------- >= ---------------------------------------- // < defined by value of name bool Employee::operator>=(const Employee& E) const { return *this > E || *this == E; } //----------------- operator == (equality) ---------------- // if name of calling and passed object are equal, // return true, otherwise false // bool Employee::operator==(const Employee& E) const { return lastName == E.lastName && firstName == E.firstName; } //----------------- operator != (inequality) ---------------- // return opposite value of operator== bool Employee::operator!=(const Employee& E) const { return !(*this == E); } //------------------------------- << --------------------------------------- // display Employee object ostream& operator<<(ostream& output, const Employee& E) { output << setw(4) << E.idNumber << setw(7) << E.salary << " " << E.lastName << " " << E.firstName << endl; return output; } I will include a check for NULL pointer but I just want to get this working and will test it on a list that includes the data I am checking. Thanks to whoever can help and as usual, this is for a course so I don't expect or want the answer, but any tips as to what might be going wrong will help immensely!

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