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• What&rsquo;s New in ASP.NET 4.0 Part Two: WebForms and Visual Studio Enhancements

  - by Rick Strahl

  In the last installment I talked about the core changes in the ASP.NET runtime that I’ve been taking advantage of. In this column, I’ll cover the changes to the Web Forms engine and some of the cool improvements in Visual Studio that make Web and general development easier. WebForms The WebForms engine is the area that has received most significant changes in ASP.NET 4.0. Probably the most widely anticipated features are related to managing page client ids and of ViewState on WebForm pages. Take Control of Your ClientIDs Unique ClientID generation in ASP.NET has been one of the most complained about “features” in ASP.NET. Although there’s a very good technical reason for these unique generated ids - they guarantee unique ids for each and every server control on a page - these unique and generated ids often get in the way of client-side JavaScript development and CSS styling as it’s often inconvenient and fragile to work with the long, generated ClientIDs. In ASP.NET 4.0 you can now specify an explicit client id mode on each control or each naming container parent control to control how client ids are generated. By default, ASP.NET generates mangled client ids for any control contained in a naming container (like a Master Page, or a User Control for example). The key to ClientID management in ASP.NET 4.0 are the new ClientIDMode and ClientIDRowSuffix properties. ClientIDMode supports four different ClientID generation settings shown below. For the following examples, imagine that you have a Textbox control named txtName inside of a master page control container on a WebForms page. <%@Page Language="C#"      MasterPageFile="~/Site.Master"     CodeBehind="WebForm2.aspx.cs"     Inherits="WebApplication1.WebForm2"  %> <asp:Content ID="content"  ContentPlaceHolderID="content"               runat="server"               ClientIDMode="Static" >       <asp:TextBox runat="server" ID="txtName" /> </asp:Content> The four available ClientIDMode values are: AutoID This is the existing behavior in ASP.NET 1.x-3.x where full naming container munging takes place. <input name="ctl00$content$txtName" type="text"        id="ctl00_content_txtName" /> This should be familiar to any ASP.NET developer and results in fairly unpredictable client ids that can easily change if the containership hierarchy changes. For example, removing the master page changes the name in this case, so if you were to move a block of script code that works against the control to a non-Master page, the script code immediately breaks. Static This option is the most deterministic setting that forces the control’s ClientID to use its ID value directly. No naming container naming at all is applied and you end up with clean client ids: <input name="ctl00$content$txtName"         type="text" id="txtName" /> Note that the name property which is used for postback variables to the server still is munged, but the ClientID property is displayed simply as the ID value that you have assigned to the control. This option is what most of us want to use, but you have to be clear on that because it can potentially cause conflicts with other controls on the page. If there are several instances of the same naming container (several instances of the same user control for example) there can easily be a client id naming conflict. Note that if you assign Static to a data-bound control, like a list child control in templates, you do not get unique ids either, so for list controls where you rely on unique id for child controls, you’ll probably want to use Predictable rather than Static. I’ll write more on this a little later when I discuss ClientIDRowSuffix. Predictable The previous two values are pretty self-explanatory. Predictable however, requires some explanation. To me at least it’s not in the least bit predictable. MSDN defines this value as follows: This algorithm is used for controls that are in data-bound controls. The ClientID value is generated by concatenating the ClientID value of the parent naming container with the ID value of the control. If the control is a data-bound control that generates multiple rows, the value of the data field specified in the ClientIDRowSuffix property is added at the end. For the GridView control, multiple data fields can be specified. If the ClientIDRowSuffix property is blank, a sequential number is added at the end instead of a data-field value. Each segment is separated by an underscore character (_). The key that makes this value a bit confusing is that it relies on the parent NamingContainer’s ClientID to build its own ClientID value. This effectively means that the value is not predictable at all but rather very tightly coupled to the parent naming container’s ClientIDMode setting. For my simple textbox example, if the ClientIDMode property of the parent naming container (Page in this case) is set to “Predictable” you’ll get this: <input name="ctl00$content$txtName" type="text"         id="content_txtName" /> which gives an id that based on walking up to the currently active naming container (the MasterPage content container) and starting the id formatting from there downward. Think of this as a semi unique name that’s guaranteed unique only for the naming container. If, on the other hand, the Page is set to “AutoID” you get the following with Predictable on txtName: <input name="ctl00$content$txtName" type="text"         id="ctl00_content_txtName" /> The latter is effectively the same as if you specified AutoID because it inherits the AutoID naming from the Page and Content Master Page control of the page. But again - predictable behavior always depends on the parent naming container and how it generates its id, so the id may not always be exactly the same as the AutoID generated value because somewhere in the NamingContainer chain the ClientIDMode setting may be set to a different value. For example, if you had another naming container in the middle that was set to Static you’d end up effectively with an id that starts with the NamingContainers id rather than the whole ctl000_content munging. The most common use for Predictable is likely to be for data-bound controls, which results in each data bound item getting a unique ClientID. Unfortunately, even here the behavior can be very unpredictable depending on which data-bound control you use - I found significant differences in how template controls in a GridView behave from those that are used in a ListView control. For example, GridView creates clean child ClientIDs, while ListView still has a naming container in the ClientID, presumably because of the template container on which you can’t set ClientIDMode. Predictable is useful, but only if all naming containers down the chain use this setting. Otherwise you’re right back to the munged ids that are pretty unpredictable. Another property, ClientIDRowSuffix, can be used in combination with ClientIDMode of Predictable to force a suffix onto list client controls. For example: <asp:GridView runat="server" ID="gvItems"              AutoGenerateColumns="false"             ClientIDMode="Static"              ClientIDRowSuffix="Id">     <Columns>     <asp:TemplateField>         <ItemTemplate>             <asp:Label runat="server" id="txtName"                        Text='<%# Eval("Name") %>'                   ClientIDMode="Predictable"/>         </ItemTemplate>     </asp:TemplateField>     <asp:TemplateField>         <ItemTemplate>         <asp:Label runat="server" id="txtId"                     Text='<%# Eval("Id") %>'                     ClientIDMode="Predictable" />         </ItemTemplate>     </asp:TemplateField>     </Columns>  </asp:GridView> generates client Ids inside of a column in the master page described earlier: <td>     <span id="txtName_0">Rick</span> </td> where the value after the underscore is the ClientIDRowSuffix field - in this case “Id” of the item data bound to the control. Note that all of the child controls require ClientIDMode=”Predictable” in order for the ClientIDRowSuffix to be applied, and the parent GridView controls need to be set to Static either explicitly or via Naming Container inheritance to give these simple names. It’s a bummer that ClientIDRowSuffix doesn’t work with Static to produce this automatically. Another real problem is that other controls process the ClientIDMode differently. For example, a ListView control processes the Predictable ClientIDMode differently and produces the following with the Static ListView and Predictable child controls: <span id="ctrl0_txtName_0">Rick</span> I couldn’t even figure out a way using ClientIDMode to get a simple ID that also uses a suffix short of falling back to manually generated ids using <%= %> expressions instead. Given the inconsistencies inside of list controls using <%= %>, ids for the ListView might not be a bad idea anyway. Inherit The final setting is Inherit, which is the default for all controls except Page. This means that controls by default inherit the parent naming container’s ClientIDMode setting. For more detailed information on ClientID behavior and different scenarios you can check out a blog post of mine on this subject: http://www.west-wind.com/weblog/posts/54760.aspx. ClientID Enhancements Summary The ClientIDMode property is a welcome addition to ASP.NET 4.0. To me this is probably the most useful WebForms feature as it allows me to generate clean IDs simply by setting ClientIDMode="Static" on either the page or inside of Web.config (in the Pages section) which applies the setting down to the entire page which is my 95% scenario. For the few cases when it matters - for list controls and inside of multi-use user controls or custom server controls) - I can use Predictable or even AutoID to force controls to unique names. For application-level page development, this is easy to accomplish and provides maximum usability for working with client script code against page controls. ViewStateMode Another area of large criticism for WebForms is ViewState. ViewState is used internally by ASP.NET to persist page-level changes to non-postback properties on controls as pages post back to the server. It’s a useful mechanism that works great for the overall mechanics of WebForms, but it can also cause all sorts of overhead for page operation as ViewState can very quickly get out of control and consume huge amounts of bandwidth in your page content. ViewState can also wreak havoc with client-side scripting applications that modify control properties that are tracked by ViewState, which can produce very unpredictable results on a Postback after client-side updates. Over the years in my own development, I’ve often turned off ViewState on pages to reduce overhead. Yes, you lose some functionality, but you can easily implement most of the common functionality in non-ViewState workarounds. Relying less on heavy ViewState controls and sticking with simpler controls or raw HTML constructs avoids getting around ViewState problems. In ASP.NET 3.x and prior, it wasn’t easy to control ViewState - you could turn it on or off and if you turned it off at the page or web.config level, you couldn’t turn it back on for specific controls. In short, it was an all or nothing approach. With ASP.NET 4.0, the new ViewStateMode property gives you more control. It allows you to disable ViewState globally either on the page or web.config level and then turn it back on for specific controls that might need it. ViewStateMode only works when EnableViewState="true" on the page or web.config level (which is the default). You can then use ViewStateMode of Disabled, Enabled or Inherit to control the ViewState settings on the page. If you’re shooting for minimal ViewState usage, the ideal situation is to set ViewStateMode to disabled on the Page or web.config level and only turn it back on particular controls: <%@Page Language="C#"      CodeBehind="WebForm2.aspx.cs"     Inherits="Westwind.WebStore.WebForm2"        ClientIDMode="Static"                ViewStateMode="Disabled"     EnableViewState="true"  %> <!-- this control has viewstate  --> <asp:TextBox runat="server" ID="txtName"  ViewStateMode="Enabled" />       <!-- this control has no viewstate - it inherits  from parent container --> <asp:TextBox runat="server" ID="txtAddress" /> Note that the EnableViewState="true" at the Page level isn’t required since it’s the default, but it’s important that the value is true. ViewStateMode has no effect if EnableViewState="false" at the page level. The main benefit of ViewStateMode is that it allows you to more easily turn off ViewState for most of the page and enable only a few key controls that might need it. For me personally, this is a perfect combination as most of my WebForm apps can get away without any ViewState at all. But some controls - especially third party controls - often don’t work well without ViewState enabled, and now it’s much easier to selectively enable controls rather than the old way, which required you to pretty much turn off ViewState for all controls that you didn’t want ViewState on. Inline HTML Encoding HTML encoding is an important feature to prevent cross-site scripting attacks in data entered by users on your site. In order to make it easier to create HTML encoded content, ASP.NET 4.0 introduces a new Expression syntax using <%: %> to encode string values. The encoding expression syntax looks like this: <%: "<script type='text/javascript'>" +     "alert('Really?');</script>" %> which produces properly encoded HTML: &lt;script type=&#39;text/javascript&#39; &gt;alert(&#39;Really?&#39;);&lt;/script&gt; Effectively this is a shortcut to: <%= HttpUtility.HtmlEncode( "<script type='text/javascript'>" + "alert('Really?');</script>") %> Of course the <%: %> syntax can also evaluate expressions just like <%= %> so the more common scenario applies this expression syntax against data your application is displaying. Here’s an example displaying some data model values: <%: Model.Address.Street %> This snippet shows displaying data from your application’s data store or more importantly, from data entered by users. Anything that makes it easier and less verbose to HtmlEncode text is a welcome addition to avoid potential cross-site scripting attacks. Although I listed Inline HTML Encoding here under WebForms, anything that uses the WebForms rendering engine including ASP.NET MVC, benefits from this feature. ScriptManager Enhancements The ASP.NET ScriptManager control in the past has introduced some nice ways to take programmatic and markup control over script loading, but there were a number of shortcomings in this control. The ASP.NET 4.0 ScriptManager has a number of improvements that make it easier to control script loading and addresses a few of the shortcomings that have often kept me from using the control in favor of manual script loading. The first is the AjaxFrameworkMode property which finally lets you suppress loading the ASP.NET AJAX runtime. Disabled doesn’t load any ASP.NET AJAX libraries, but there’s also an Explicit mode that lets you pick and choose the library pieces individually and reduce the footprint of ASP.NET AJAX script included if you are using the library. There’s also a new EnableCdn property that forces any script that has a new WebResource attribute CdnPath property set to a CDN supplied URL. If the script has this Attribute property set to a non-null/empty value and EnableCdn is enabled on the ScriptManager, that script will be served from the specified CdnPath. [assembly: WebResource(    "Westwind.Web.Resources.ww.jquery.js",    "application/x-javascript",    CdnPath =  "http://mysite.com/scripts/ww.jquery.min.js")] Cool, but a little too static for my taste since this value can’t be changed at runtime to point at a debug script as needed, for example. Assembly names for loading scripts from resources can now be simple names rather than fully qualified assembly names, which make it less verbose to reference scripts from assemblies loaded from your bin folder or the assembly reference area in web.config: <asp:ScriptManager runat="server" id="Id"          EnableCdn="true"         AjaxFrameworkMode="disabled">     <Scripts>         <asp:ScriptReference          Name="Westwind.Web.Resources.ww.jquery.js"         Assembly="Westwind.Web" />     </Scripts>        </asp:ScriptManager> The ScriptManager in 4.0 also supports script combining via the CompositeScript tag, which allows you to very easily combine scripts into a single script resource served via ASP.NET. Even nicer: You can specify the URL that the combined script is served with. Check out the following script manager markup that combines several static file scripts and a script resource into a single ASP.NET served resource from a static URL (allscripts.js): <asp:ScriptManager runat="server" id="Id"          EnableCdn="true"         AjaxFrameworkMode="disabled">     <CompositeScript          Path="~/scripts/allscripts.js">         <Scripts>             <asp:ScriptReference                    Path="~/scripts/jquery.js" />             <asp:ScriptReference                    Path="~/scripts/ww.jquery.js" />             <asp:ScriptReference            Name="Westwind.Web.Resources.editors.js"                 Assembly="Westwind.Web" />         </Scripts>     </CompositeScript> </asp:ScriptManager> When you render this into HTML, you’ll see a single script reference in the page: <script src="scripts/allscripts.debug.js"          type="text/javascript"></script> All you need to do to make this work is ensure that allscripts.js and allscripts.debug.js exist in the scripts folder of your application - they can be empty but the file has to be there. This is pretty cool, but you want to be real careful that you use unique URLs for each combination of scripts you combine or else browser and server caching will easily screw you up royally. The script manager also allows you to override native ASP.NET AJAX scripts now as any script references defined in the Scripts section of the ScriptManager trump internal references. So if you want custom behavior or you want to fix a possible bug in the core libraries that normally are loaded from resources, you can now do this simply by referencing the script resource name in the Name property and pointing at System.Web for the assembly. Not a common scenario, but when you need it, it can come in real handy. Still, there are a number of shortcomings in this control. For one, the ScriptManager and ClientScript APIs still have no common entry point so control developers are still faced with having to check and support both APIs to load scripts so that controls can work on pages that do or don’t have a ScriptManager on the page. The CdnUrl is static and compiled in, which is very restrictive. And finally, there’s still no control over where scripts get loaded on the page - ScriptManager still injects scripts into the middle of the HTML markup rather than in the header or optionally the footer. This, in turn, means there is little control over script loading order, which can be problematic for control developers. MetaDescription, MetaKeywords Page Properties There are also a number of additional Page properties that correspond to some of the other features discussed in this column: ClientIDMode, ClientTarget and ViewStateMode. Another minor but useful feature is that you can now directly access the MetaDescription and MetaKeywords properties on the Page object to set the corresponding meta tags programmatically. Updating these values programmatically previously required either <%= %> expressions in the page markup or dynamic insertion of literal controls into the page. You can now just set these properties programmatically on the Page object in any Control derived class on the page or the Page itself: Page.MetaKeywords = "ASP.NET,4.0,New Features"; Page.MetaDescription = "This article discusses the new features in ASP.NET 4.0"; Note, that there’s no corresponding ASP.NET tag for the HTML Meta element, so the only way to specify these values in markup and access them is via the @Page tag: <%@Page Language="C#"      CodeBehind="WebForm2.aspx.cs"     Inherits="Westwind.WebStore.WebForm2"      ClientIDMode="Static"                MetaDescription="Article that discusses what's                      new in ASP.NET 4.0"     MetaKeywords="ASP.NET,4.0,New Features" %> Nothing earth shattering but quite convenient. Visual Studio 2010 Enhancements for Web Development For Web development there are also a host of editor enhancements in Visual Studio 2010. Some of these are not Web specific but they are useful for Web developers in general. Text Editors Throughout Visual Studio 2010, the text editors have all been updated to a new core engine based on WPF which provides some interesting new features for various code editors including the nice ability to zoom in and out with Ctrl-MouseWheel to quickly change the size of text. There are many more API options to control the editor and although Visual Studio 2010 doesn’t yet use many of these features, we can look forward to enhancements in add-ins and future editor updates from the various language teams that take advantage of the visual richness that WPF provides to editing. On the negative side, I’ve noticed that occasionally the code editor and especially the HTML and JavaScript editors will lose the ability to use various navigation keys like arrows, back and delete keys, which requires closing and reopening the documents at times. This issue seems to be well documented so I suspect this will be addressed soon with a hotfix or within the first service pack. Overall though, the code editors work very well, especially given that they were re-written completely using WPF, which was one of my big worries when I first heard about the complete redesign of the editors. Multi-Targeting Visual Studio now targets all versions of the .NET framework from 2.0 forward. You can use Visual Studio 2010 to work on your ASP.NET 2, 3.0 and 3.5 applications which is a nice way to get your feet wet with the new development environment without having to make changes to existing applications. It’s nice to have one tool to work in for all the different versions. Multi-Monitor Support One cool feature of Visual Studio 2010 is the ability to drag windows out of the Visual Studio environment and out onto the desktop including onto another monitor easily. Since Web development often involves working with a host of designers at the same time - visual designer, HTML markup window, code behind and JavaScript editor - it’s really nice to be able to have a little more screen real estate to work on each of these editors. Microsoft made a welcome change in the environment. IntelliSense Snippets for HTML and JavaScript Editors The HTML and JavaScript editors now finally support IntelliSense scripts to create macro-based template expansions that have been in the core C# and Visual Basic code editors since Visual Studio 2005. Snippets allow you to create short XML-based template definitions that can act as static macros or real templates that can have replaceable values that can be embedded into the expanded text. The XML syntax for these snippets is straight forward and it’s pretty easy to create custom snippets manually. You can easily create snippets using XML and store them in your custom snippets folder (C:\Users\rstrahl\Documents\Visual Studio 2010\Code Snippets\Visual Web Developer\My HTML Snippets and My JScript Snippets), but it helps to use one of the third-party tools that exist to simplify the process for you. I use SnippetEditor, by Bill McCarthy, which makes short work of creating snippets interactively (http://snippeteditor.codeplex.com/). Note: You may have to manually add the Visual Studio 2010 User specific Snippet folders to this tool to see existing ones you’ve created. Code snippets are some of the biggest time savers and HTML editing more than anything deals with lots of repetitive tasks that lend themselves to text expansion. Visual Studio 2010 includes a slew of built-in snippets (that you can also customize!) and you can create your own very easily. If you haven’t done so already, I encourage you to spend a little time examining your coding patterns and find the repetitive code that you write and convert it into snippets. I’ve been using CodeRush for this for years, but now you can do much of the basic expansion natively for HTML and JavaScript snippets. jQuery Integration Is Now Native jQuery is a popular JavaScript library and recently Microsoft has recently stated that it will become the primary client-side scripting technology to drive higher level script functionality in various ASP.NET Web projects that Microsoft provides. In Visual Studio 2010, the default full project template includes jQuery as part of a new project including the support files that provide IntelliSense (-vsdoc files). IntelliSense support for jQuery is now also baked into Visual Studio 2010, so unlike Visual Studio 2008 which required a separate download, no further installs are required for a rich IntelliSense experience with jQuery. Summary ASP.NET 4.0 brings many useful improvements to the platform, but thankfully most of the changes are incremental changes that don’t compromise backwards compatibility and they allow developers to ease into the new features one feature at a time. None of the changes in ASP.NET 4.0 or Visual Studio 2010 are monumental or game changers. The bigger features are language and .NET Framework changes that are also optional. This ASP.NET and tools release feels more like fine tuning and getting some long-standing kinks worked out of the platform. It shows that the ASP.NET team is dedicated to paying attention to community feedback and responding with changes to the platform and development environment based on this feedback. If you haven’t gotten your feet wet with ASP.NET 4.0 and Visual Studio 2010, there’s no reason not to give it a shot now - the ASP.NET 4.0 platform is solid and Visual Studio 2010 works very well for a brand new release. Check it out. © Rick Strahl, West Wind Technologies, 2005-2010Posted in ASP.NET  

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• iPhone SDK vs Windows Phone 7 Series SDK Challenge, Part 1: Hello World!

  In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series.  My goal is to do as much of an apples-to-apples comparison as I can.  This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. Hello World! Of course no first post would be allowed if it didnt focus on the hello world scenario.  The iPhone SDK follows that tradition with the Your First iPhone Application walkthrough.  I will say that the developer documentation for iPhone is pretty good.  There are plenty of walkthoughs and they break things down into nicely sized steps and do a good job of bringing the user along.  As expected, this application is quite simple.  It comprises of a text box, a label, and a button.  When you push the button, the label changes to Hello plus the  word you typed into the text box.  Makes perfect sense for a starter application.  Theres not much to this but it covers a few basic elements: Laying out basic UI Handling user input Hooking up events Formatting text     So, lets get started building a similar app for Windows Phone 7 Series! Implementing the UI: UI in Silverlight (and therefore Windows Phone 7) is defined in XAML, which is a declarative XML language also used by WPF on the desktop.  For anyone thats familiar with similar types of markup, its relatively straightforward to learn, but has a lot of power in it once you get it figured out.  Well talk more about that. This UI is very simple.  When I look at this, I note a couple of things: Elements are arranged vertically They are all centered So, lets create our Application and then start with the UI.  Once you have the the VS 2010 Express for Windows Phone tool running, create a new Windows Phone Project, and call it Hello World: Once created, youll see the designer on one side and your XAML on the other: Now, we can create our UI in one of three ways: Use the designer in Visual Studio to drag and drop the components Use the designer in Expression Blend 4 to drag and drop the components Enter the XAML by hand in either of the above Well start with (1), then kind of move to (3) just for instructional value. To develop this UI in the designer: First, delete all of the markup between inside of the Grid element (LayoutRoot).  You should be left with just this XAML for your MainPage.xaml (i shortened all the xmlns declarations below for brevity): 1: <phoneNavigation:PhoneApplicationPage 2: x:Class="HelloWorld.MainPage" 3: xmlns="...[snip]" 4: FontFamily="{StaticResource PhoneFontFamilyNormal}" 5: FontSize="{StaticResource PhoneFontSizeNormal}" 6: Foreground="{StaticResource PhoneForegroundBrush}"> 7:   8: <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}"> 9:   10: </Grid> 11:   12: </phoneNavigation:PhoneApplicationPage> .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; }   Well be adding XAML at line 9, so thats the important part. Now, Click on the center area of the phone surface Open the Toolbox and double click StackPanel Double click TextBox Double click TextBlock Double click Button That will create the necessary UI elements but they wont be arranged quite right.  Well fix it in a second.    Heres the XAML that we end up with: 1: <StackPanel Height="100" HorizontalAlignment="Left" Margin="10,10,0,0" Name="stackPanel1" VerticalAlignment="Top" Width="200"> 2: <TextBox Height="32" Name="textBox1" Text="TextBox" Width="100" /> 3: <TextBlock Height="23" Name="textBlock1" Text="TextBlock" /> 4: <Button Content="Button" Height="70" Name="button1" Width="160" /> 5: </StackPanel> .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; } The designer does its best at guessing what we want, but in this case we want things to be a bit simpler. So well just clean it up a bit.  We want the items to be centered and we want them to have a little bit of a margin on either side, so heres what we end up with.  Ive also made it match the values and style from the iPhone app: 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <TextBlock Name="textBlock1" HorizontalAlignment="Center" Margin="0,100,0,0" Text="Hello You!" /> 4: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello"/> 5: </StackPanel> .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; } Now lets take a look at what weve done there. Line 1: We removed all of the formatting from the StackPanel, except for Margin, as thats all we need.  Since our parent element is a Grid, by default the StackPanel will be sized to fit in that space.  The Margin says that we want to reserve 10 pixels on each side of the StackPanel. Line 2: Weve set the HorizontalAlignment of the TextBox to Stretch, which says that it should fill its parents size horizontally.  We want to do this so the TextBox is always full-width.  We also set TextAlignment to Center, to center the text. Line 3: In contrast to the TextBox above, we dont care how wide the TextBlock is, just so long as it is big enough for its text.  Thatll happen automatically, so we just set its Horizontal alignment to Center.  We also set a Margin above the TextBlock of 100 pixels to bump it down a bit, per the iPhone UI. Line 4: We do the same things here as in Line 3. Heres how the UI looks in the designer: Believe it or not, were almost done! Implementing the App Logic Now, we want the TextBlock to change its text when the Button is clicked.  In the designer, double click the Button to be taken to the Event Handler for the Buttons Click event.  In that event handler, we take the Text property from the TextBox, and format it into a string, then set it into the TextBlock.  Thats it! 1: private void button1_Click(object sender, RoutedEventArgs e) 2: { 3: string name = textBox1.Text; 4:   5: // if there isn't a name set, just use "World" 6: if (String.IsNullOrEmpty(name)) 7: { 8: name = "World"; 9: } 10:   11: // set the value into the TextBlock 12: textBlock1.Text = String.Format("Hello {0}!", name); 13:   14: } .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; } We use the String.Format() method to handle the formatting for us.    Now all thats left is to test the app in the Windows Phone Emulator and verify it does what we think it does! And it does! Comparing against the iPhone Looking at the iPhone example, there are basically three things that you have to touch as the developer: 1) The UI in the Nib file 2) The app delegate 3) The view controller Counting lines is a bit tricky here, but to try to keep this even, Im going to only count lines of code that I could not have (or would not have) generated with the tooling.  Meaning, Im not counting XAML and Im not counting operations that happen in the Nib file with the XCode designer tool.  So in the case of the above, even though I modified the XAML, I could have done all of those operations using the visual designer tool.  And normally I would have, but the XAML is more instructive (and less steps!).  Im interested in things that I, as the developer have to figure out in code.  Im also not counting lines that just have a curly brace on them, or lines that are generated for me (e.g. method names that are generated for me when I make a connection, etc.) So, by that count, heres what I get from the code listing for the iPhone app found here: HelloWorldAppDelegate.h: 6 HelloWorldAppDelegate.m: 12 MyViewController.h: 8 MyViewController.m: 18 Which gives me a grand total of about 44 lines of code on iPhone.  I really do recommend looking at the iPhone code for a comparison to the above. Now, for the Windows Phone 7 Series application, the only code I typed was in the event handler above Main.Xaml.cs: 4 So a total of 4 lines of code on Windows Phone 7.  And more importantly, the process is just A LOT simpler.  For example, I was surprised that the User Interface Designer in XCode doesnt automatically create instance variables for me and wire them up to the corresponding elements.  I assumed I wouldnt have to write this code myself (and risk getting it wrong!).  I dont need to worry about view controllers or anything.  I just write my code.  This blog post up to this point has covered almost every aspect of this apps development in a few pages.  The iPhone tutorial has 5 top level steps with 2-3 sub sections of each. Now, its worth pointing out that the iPhone development model uses the Model View Controller (MVC) pattern, which is a very flexible and powerful pattern that enforces proper separation of concerns.  But its fairly complex and difficult to understand when you first walk up to it.  Here at Microsoft weve dabbled in MVC a bit, with frameworks like MFC on Visual C++ and with the ASP.NET MVC framework now.  Both are very powerful frameworks.  But one of the reasons weve stayed away from MVC with client UI frameworks is that its difficult to tool.  We havent seen the type of value that beats double click, write code! for the broad set of scenarios. Another thing to think about is how many of those lines of code were focused on my apps functionality?.  Or, the converse of How many lines of code were boilerplate plumbing?  In both examples, the actual number of functional code lines is similar.  I count most of them in MyViewController.m, in the changeGreeting method.  Its about 7 lines of code that do the work of taking the value from the TextBox and putting it into the label.  Versus 4 on the Windows Phone 7 side.  But, unfortunately, on iPhone I still have to write that other 37 lines of code, just to get there. 10% of the code, 1 file instead of 4, its just much simpler. Making Some Tweaks It turns out, I can actually do this application with ZERO  lines of code, if Im willing to change the spec a bit. The data binding functionality in Silverlight is incredibly powerful.  And what I can do is databind the TextBoxs value directly to the TextBlock.  Take some time looking at this XAML below.  Youll see that I have added another nested StackPanel and two more TextBlocks.  Why?  Because thats how I build that string, and the nested StackPanel will lay things out Horizontally for me, as specified by the Orientation property. 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,100,0,0" > 4: <TextBlock Text="Hello " /> 5: <TextBlock Name="textBlock1" Text="{Binding ElementName=textBox1, Path=Text}" /> 6: <TextBlock Text="!" /> 7: </StackPanel> 8: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello" Click="button1_Click" /> 9: </StackPanel> .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; } Now, the real action is there in the bolded TextBlock.Text property: Text="{Binding ElementName=textBox1, Path=Text}" .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; } That does all the heavy lifting.  It sets up a databinding between the TextBox.Text property on textBox1 and the TextBlock.Text property on textBlock1. As I change the text of the TextBox, the label updates automatically. In fact, I dont even need the button any more, so I could get rid of that altogether.  And no button means no event handler.  No event handler means no C# code at all.  Did 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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• ubuntu 12.04 python problem or?

  - by Trki

  Hi i am trying to fix this for a long time but without success. When i open my zsh terminal i get this error: (terminal is working but error appear) Welcome to the world of tomorrow! virtualenvwrapper_run_hook:12: permission denied: virtualenvwrapper.sh: There was a problem running the initialization hooks. If Python could not import the module virtualenvwrapper.hook_loader, check that virtualenv has been installed for VIRTUALENVWRAPPER_PYTHON= and that PATH is set properly. I tried few things but... dont know how to solve it. Somehow during looking for a search i found i should post here an output of: ? sudo dpkg --configure -a Setting up python-pip (1.0-1build1) ... /var/lib/dpkg/info/python-pip.postinst: 6: /var/lib/dpkg/info/python-pip.postinst: pycompile: not found dpkg: error processing python-pip (--configure): subprocess installed post-installation script returned error exit status 127 Setting up libc-dev-bin (2.15-0ubuntu10.5) ... Setting up gnome-control-center-data (1:3.4.2-0ubuntu0.13) ... Setting up linux-libc-dev (3.2.0-56.86) ... Setting up python-virtualenv (1.7.1.2-1) ... /var/lib/dpkg/info/python-virtualenv.postinst: 6: /var/lib/dpkg/info/python-virtualenv.postinst: pycompile: not found dpkg: error processing python-virtualenv (--configure): subprocess installed post-installation script returned error exit status 127 Setting up libglib2.0-0 (2.32.4-0ubuntu1) ... Setting up libglib2.0-0:i386 (2.32.4-0ubuntu1) ... Setting up gimp (2.6.12-1ubuntu1.2) ... /var/lib/dpkg/info/gimp.postinst: 11: /var/lib/dpkg/info/gimp.postinst: pycompile: not found dpkg: error processing gimp (--configure): subprocess installed post-installation script returned error exit status 127 Setting up libpolkit-gobject-1-0 (0.104-1ubuntu1.1) ... Setting up libgnome-control-center1 (1:3.4.2-0ubuntu0.13) ... Setting up libnm-util2 (0.9.4.0-0ubuntu4.3) ... Setting up libc6-dev (2.15-0ubuntu10.5) ... Setting up libpulse-mainloop-glib0 (1:1.1-0ubuntu15.4) ... dpkg: dependency problems prevent configuration of virtualenvwrapper: virtualenvwrapper depends on python-virtualenv; however: Package python-virtualenv is not configured yet. dpkg: error processing virtualenvwrapper (--configure): dependency problems - leaving unconfigured Setting up libpolkit-agent-1-0 (0.104-1ubuntu1.1) ... Setting up libupower-glib1 (0.9.15-3git1ubuntu0.1) ... Setting up libaccountsservice0 (0.6.15-2ubuntu9.6.1) ... Setting up libpolkit-backend-1-0 (0.104-1ubuntu1.1) ... Setting up libglib2.0-bin (2.32.4-0ubuntu1) ... Setting up libnm-glib4 (0.9.4.0-0ubuntu4.3) ... Setting up policykit-1 (0.104-1ubuntu1.1) ... Setting up gnome-settings-daemon (3.4.2-0ubuntu0.6.4) ... Setting up accountsservice (0.6.15-2ubuntu9.6.1) ... dpkg: error processing ubuntu-system-service (--configure): Package is in a very bad inconsistent state - you should reinstall it before attempting configuration. Processing triggers for libc-bin ... ldconfig deferred processing now taking place Errors were encountered while processing: python-pip python-virtualenv gimp virtualenvwrapper ubuntu-system-service Also: ? python --version zsh: command not found: python Part of my ~/.zshrc # python virtual env wrapper if [ -f ~/.local/bin/virtualenvwrapper.sh ]; then export WORKON_HOME=~/.virtualenvs source ~/.local/bin/virtualenvwrapper.sh plugins=("${plugins[@]}" virtualenvwrapper) fi # pythonbrew [[ -s ~/.pythonbrew/etc/bashrc ]] && source ~/.pythonbrew/etc/bashrc Part os zsh -xv # # Invoke the initialization functions # virtualenvwrapper_initialize +/home/trki/.local/bin/virtualenvwrapper.sh:1179> virtualenvwrapper_initialize +virtualenvwrapper_initialize:1> virtualenvwrapper_derive_workon_home +virtualenvwrapper_derive_workon_home:1> typeset 'workon_home_dir=/home/trki/.virtualenvs' +virtualenvwrapper_derive_workon_home:5> [ /home/trki/.virtualenvs '=' '' ']' +virtualenvwrapper_derive_workon_home:12> echo /home/trki/.virtualenvs +virtualenvwrapper_derive_workon_home:12> unset GREP_OPTIONS +virtualenvwrapper_derive_workon_home:12> grep '^[^/~]' +virtualenvwrapper_derive_workon_home:21> echo /home/trki/.virtualenvs +virtualenvwrapper_derive_workon_home:21> unset GREP_OPTIONS +virtualenvwrapper_derive_workon_home:21> egrep '([\$~]|//)' +virtualenvwrapper_derive_workon_home:30> echo /home/trki/.virtualenvs +virtualenvwrapper_derive_workon_home:31> return 0 +virtualenvwrapper_initialize:1> export 'WORKON_HOME=/home/trki/.virtualenvs' +virtualenvwrapper_initialize:3> virtualenvwrapper_verify_workon_home -q +virtualenvwrapper_verify_workon_home:1> RC=0 +virtualenvwrapper_verify_workon_home:2> [ ! -d /home/trki/.virtualenvs/ ']' +virtualenvwrapper_verify_workon_home:11> return 0 +virtualenvwrapper_initialize:6> [ /home/trki/.virtualenvs '=' '' ']' +virtualenvwrapper_initialize:11> virtualenvwrapper_run_hook initialize +virtualenvwrapper_run_hook:1> typeset hook_script +virtualenvwrapper_run_hook:2> typeset result +virtualenvwrapper_run_hook:4> hook_script=+virtualenvwrapper_run_hook:4> virtualenvwrapper_tempfile initialize-hook +virtualenvwrapper_tempfile:2> typeset 'suffix=initialize-hook' +virtualenvwrapper_tempfile:3> typeset file +virtualenvwrapper_tempfile:5> file=+virtualenvwrapper_tempfile:5> virtualenvwrapper_mktemp -t virtualenvwrapper-initialize-hook-XXXXXXXXXX +virtualenvwrapper_mktemp:1> mktemp -t virtualenvwrapper-initialize-hook-XXXXXXXXXX +virtualenvwrapper_tempfile:5> file=/tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 +virtualenvwrapper_tempfile:6> [ 0 -ne 0 ']' +virtualenvwrapper_tempfile:6> [ -z /tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 ']' +virtualenvwrapper_tempfile:6> [ ! -f /tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 ']' +virtualenvwrapper_tempfile:11> echo /tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 +virtualenvwrapper_tempfile:12> return 0 +virtualenvwrapper_run_hook:4> hook_script=/tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 +virtualenvwrapper_run_hook:11> cd /home/trki/.virtualenvs +cd:1> [[ x/home/trki/.virtualenvs == x... ]] +cd:3> [[ x/home/trki/.virtualenvs == x.... ]] +cd:5> [[ x/home/trki/.virtualenvs == x..... ]] +cd:7> [[ x/home/trki/.virtualenvs == x...... ]] +cd:9> [ -d /home/trki/.autoenv ']' +cd:13> cd /home/trki/.virtualenvs +virtualenvwrapper_run_hook:12> '' -m virtualenvwrapper.hook_loader --script /tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 initialize virtualenvwrapper_run_hook:12: permission denied: +virtualenvwrapper_run_hook:15> result=126 +virtualenvwrapper_run_hook:17> [ 126 -eq 0 ']' +virtualenvwrapper_run_hook:27> [ initialize '=' initialize ']' +virtualenvwrapper_run_hook:29> cat - virtualenvwrapper.sh: There was a problem running the initialization hooks. If Python could not import the module virtualenvwrapper.hook_loader, check that virtualenv has been installed for VIRTUALENVWRAPPER_PYTHON= and that PATH is set properly. +virtualenvwrapper_run_hook:38> rm -f /tmp/virtualenvwrapper-initialize-hook-OhY86PXmo7 +virtualenvwrapper_run_hook:39> return 126 +virtualenvwrapper_initialize:13> virtualenvwrapper_setup_tab_completion +virtualenvwrapper_setup_tab_completion:1> [ -n '' ']' +virtualenvwrapper_setup_tab_completion:20> [ -n 4.3.17 ']' +virtualenvwrapper_setup_tab_completion:30> compctl -K _virtualenvs workon rmvirtualenv cpvirtualenv showvirtualenv +virtualenvwrapper_setup_tab_completion:31> compctl -K _cdvirtualenv_complete cdvirtualenv +virtualenvwrapper_setup_tab_completion:32> compctl -K _cdsitepackages_complete cdsitepackages +virtualenvwrapper_initialize:15> return 0 +/home/trki/.zshrc:17> plugins=( git python django symfony2 zsh-syntax-highlighting composer history-substring-search virtualenvwrapper ) # pythonbrew [[ -s ~/.pythonbrew/etc/bashrc ]] && source ~/.pythonbrew/etc/bashrc +/home/trki/.zshrc:21> [[ -s /home/trki/.pythonbrew/etc/bashrc ]] Also when i try to open ubuntu software center absolutly nothing happens. No idea what to do now.

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• Node.js Adventure - Storage Services and Service Runtime

  - by Shaun

  When I described on how to host a Node.js application on Windows Azure, one of questions might be raised about how to consume the vary Windows Azure services, such as the storage, service bus, access control, etc.. Interact with windows azure services is available in Node.js through the Windows Azure Node.js SDK, which is a module available in NPM. In this post I would like to describe on how to use Windows Azure Storage (a.k.a. WAS) as well as the service runtime.   Consume Windows Azure Storage Let’s firstly have a look on how to consume WAS through Node.js. As we know in the previous post we can host Node.js application on Windows Azure Web Site (a.k.a. WAWS) as well as Windows Azure Cloud Service (a.k.a. WACS). In theory, WAWS is also built on top of WACS worker roles with some more features. Hence in this post I will only demonstrate for hosting in WACS worker role. The Node.js code can be used when consuming WAS when hosted on WAWS. But since there’s no roles in WAWS, the code for consuming service runtime mentioned in the next section cannot be used for WAWS node application. We can use the solution that I created in my last post. Alternatively we can create a new windows azure project in Visual Studio with a worker role, add the “node.exe” and “index.js” and install “express” and “node-sqlserver” modules, make all files as “Copy always”. In order to use windows azure services we need to have Windows Azure Node.js SDK, as knows as a module named “azure” which can be installed through NPM. Once we downloaded and installed, we need to include them in our worker role project and make them as “Copy always”. You can use my “Copy all always” tool mentioned in my last post to update the currently worker role project file. You can also find the source code of this tool here. The source code of Windows Azure SDK for Node.js can be found in its GitHub page. It contains two parts. One is a CLI tool which provides a cross platform command line package for Mac and Linux to manage WAWS and Windows Azure Virtual Machines (a.k.a. WAVM). The other is a library for managing and consuming vary windows azure services includes tables, blobs, queues, service bus and the service runtime. I will not cover all of them but will only demonstrate on how to use tables and service runtime information in this post. You can find the full document of this SDK here. Back to Visual Studio and open the “index.js”, let’s continue our application from the last post, which was working against Windows Azure SQL Database (a.k.a. WASD). The code should looks like this. 1: var express = require("express"); 2: var sql = require("node-sqlserver"); 3:  4: var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd={PASSWORD};Encrypt=yes;Connection Timeout=30;"; 5: var port = 80; 6:  7: var app = express(); 8:  9: app.configure(function () { 10: app.use(express.bodyParser()); 11: }); 12:  13: app.get("/", function (req, res) { 14: sql.open(connectionString, function (err, conn) { 15: if (err) { 16: console.log(err); 17: res.send(500, "Cannot open connection."); 18: } 19: else { 20: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 21: if (err) { 22: console.log(err); 23: res.send(500, "Cannot retrieve records."); 24: } 25: else { 26: res.json(results); 27: } 28: }); 29: } 30: }); 31: }); 32:  33: app.get("/text/:key/:culture", function (req, res) { 34: sql.open(connectionString, function (err, conn) { 35: if (err) { 36: console.log(err); 37: res.send(500, "Cannot open connection."); 38: } 39: else { 40: var key = req.params.key; 41: var culture = req.params.culture; 42: var command = "SELECT * FROM [Resource] WHERE [Key] = '" + key + "' AND [Culture] = '" + culture + "'"; 43: conn.queryRaw(command, function (err, results) { 44: if (err) { 45: console.log(err); 46: res.send(500, "Cannot retrieve records."); 47: } 48: else { 49: res.json(results); 50: } 51: }); 52: } 53: }); 54: }); 55:  56: app.get("/sproc/:key/:culture", function (req, res) { 57: sql.open(connectionString, function (err, conn) { 58: if (err) { 59: console.log(err); 60: res.send(500, "Cannot open connection."); 61: } 62: else { 63: var key = req.params.key; 64: var culture = req.params.culture; 65: var command = "EXEC GetItem '" + key + "', '" + culture + "'"; 66: conn.queryRaw(command, function (err, results) { 67: if (err) { 68: console.log(err); 69: res.send(500, "Cannot retrieve records."); 70: } 71: else { 72: res.json(results); 73: } 74: }); 75: } 76: }); 77: }); 78:  79: app.post("/new", function (req, res) { 80: var key = req.body.key; 81: var culture = req.body.culture; 82: var val = req.body.val; 83:  84: sql.open(connectionString, function (err, conn) { 85: if (err) { 86: console.log(err); 87: res.send(500, "Cannot open connection."); 88: } 89: else { 90: var command = "INSERT INTO [Resource] VALUES ('" + key + "', '" + culture + "', N'" + val + "')"; 91: conn.queryRaw(command, function (err, results) { 92: if (err) { 93: console.log(err); 94: res.send(500, "Cannot retrieve records."); 95: } 96: else { 97: res.send(200, "Inserted Successful"); 98: } 99: }); 100: } 101: }); 102: }); 103:  104: app.listen(port); Now let’s create a new function, copy the records from WASD to table service. 1. Delete the table named “resource”. 2. Create a new table named “resource”. These 2 steps ensures that we have an empty table. 3. Load all records from the “resource” table in WASD. 4. For each records loaded from WASD, insert them into the table one by one. 5. Prompt to user when finished. In order to use table service we need the storage account and key, which can be found from the developer portal. Just select the storage account and click the Manage Keys button. Then create two local variants in our Node.js application for the storage account name and key. Since we need to use WAS we need to import the azure module. Also I created another variant stored the table name. In order to work with table service I need to create the storage client for table service. This is very similar as the Windows Azure SDK for .NET. As the code below I created a new variant named “client” and use “createTableService”, specified my storage account name and key. 1: var azure = require("azure"); 2: var storageAccountName = "synctile"; 3: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 4: var tableName = "resource"; 5: var client = azure.createTableService(storageAccountName, storageAccountKey); Now create a new function for URL “/was/init” so that we can trigger it through browser. Then in this function we will firstly load all records from WASD. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: } 18: } 19: }); 20: } 21: }); 22: }); When we succeed loaded all records we can start to transform them into table service. First I need to recreate the table in table service. This can be done by deleting and creating the table through table client I had just created previously. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: } 27: }); 28: }); 29: } 30: } 31: }); 32: } 33: }); 34: }); As you can see, the azure SDK provide its methods in callback pattern. In fact, almost all modules in Node.js use the callback pattern. For example, when I deleted a table I invoked “deleteTable” method, provided the name of the table and a callback function which will be performed when the table had been deleted or failed. Underlying, the azure module will perform the table deletion operation in POSIX async threads pool asynchronously. And once it’s done the callback function will be performed. This is the reason we need to nest the table creation code inside the deletion function. If we perform the table creation code after the deletion code then they will be invoked in parallel. Next, for each records in WASD I created an entity and then insert into the table service. Finally I send the response to the browser. Can you find a bug in the code below? I will describe it later in this post. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: // transform the records 26: for (var i = 0; i < results.rows.length; i++) { 27: var entity = { 28: "PartitionKey": results.rows[i][1], 29: "RowKey": results.rows[i][0], 30: "Value": results.rows[i][2] 31: }; 32: client.insertEntity(tableName, entity, function (error) { 33: if (error) { 34: error["target"] = "insertEntity"; 35: res.send(500, error); 36: } 37: else { 38: console.log("entity inserted"); 39: } 40: }); 41: } 42: // send the 43: console.log("all done"); 44: res.send(200, "All done!"); 45: } 46: }); 47: }); 48: } 49: } 50: }); 51: } 52: }); 53: }); Now we can publish it to the cloud and have a try. But normally we’d better test it at the local emulator first. In Node.js SDK there are three build-in properties which provides the account name, key and host address for local storage emulator. We can use them to initialize our table service client. We also need to change the SQL connection string to let it use my local database. The code will be changed as below. 1: // windows azure sql database 2: //var connectionString = "Driver={SQL Server Native Client 10.0};Server=tcp:ac6271ya9e.database.windows.net,1433;Database=synctile;Uid=shaunxu@ac6271ya9e;Pwd=eszqu94XZY;Encrypt=yes;Connection Timeout=30;"; 3: // sql server 4: var connectionString = "Driver={SQL Server Native Client 11.0};Server={.};Database={Caspar};Trusted_Connection={Yes};"; 5:  6: var azure = require("azure"); 7: var storageAccountName = "synctile"; 8: var storageAccountKey = "/cOy9L7xysXOgPYU9FjDvjrRAhaMX/5tnOpcjqloPNDJYucbgTy7MOrAW7CbUg6PjaDdmyl+6pkwUnKETsPVNw=="; 9: var tableName = "resource"; 10: // windows azure storage 11: //var client = azure.createTableService(storageAccountName, storageAccountKey); 12: // local storage emulator 13: var client = azure.createTableService(azure.ServiceClient.DEVSTORE_STORAGE_ACCOUNT, azure.ServiceClient.DEVSTORE_STORAGE_ACCESS_KEY, azure.ServiceClient.DEVSTORE_TABLE_HOST); Now let’s run the application and navigate to “localhost:12345/was/init” as I hosted it on port 12345. We can find it transformed the data from my local database to local table service. Everything looks fine. But there is a bug in my code. If we have a look on the Node.js command window we will find that it sent response before all records had been inserted, which is not what I expected. The reason is that, as I mentioned before, Node.js perform all IO operations in non-blocking model. When we inserted the records we executed the table service insert method in parallel, and the operation of sending response was also executed in parallel, even though I wrote it at the end of my logic. The correct logic should be, when all entities had been copied to table service with no error, then I will send response to the browser, otherwise I should send error message to the browser. To do so I need to import another module named “async”, which helps us to coordinate our asynchronous code. Install the module and import it at the beginning of the code. Then we can use its “forEach” method for the asynchronous code of inserting table entities. The first argument of “forEach” is the array that will be performed. The second argument is the operation for each items in the array. And the third argument will be invoked then all items had been performed or any errors occurred. Here we can send our response to browser. 1: app.get("/was/init", function (req, res) { 2: // load all records from windows azure sql database 3: sql.open(connectionString, function (err, conn) { 4: if (err) { 5: console.log(err); 6: res.send(500, "Cannot open connection."); 7: } 8: else { 9: conn.queryRaw("SELECT * FROM [Resource]", function (err, results) { 10: if (err) { 11: console.log(err); 12: res.send(500, "Cannot retrieve records."); 13: } 14: else { 15: if (results.rows.length > 0) { 16: // begin to transform the records into table service 17: // recreate the table named 'resource' 18: client.deleteTable(tableName, function (error) { 19: client.createTableIfNotExists(tableName, function (error) { 20: if (error) { 21: error["target"] = "createTableIfNotExists"; 22: res.send(500, error); 23: } 24: else { 25: async.forEach(results.rows, 26: // transform the records 27: function (row, callback) { 28: var entity = { 29: "PartitionKey": row[1], 30: "RowKey": row[0], 31: "Value": row[2] 32: }; 33: client.insertEntity(tableName, entity, function (error) { 34: if (error) { 35: callback(error); 36: } 37: else { 38: console.log("entity inserted."); 39: callback(null); 40: } 41: }); 42: }, 43: // send reponse 44: function (error) { 45: if (error) { 46: error["target"] = "insertEntity"; 47: res.send(500, error); 48: } 49: else { 50: console.log("all done"); 51: res.send(200, "All done!"); 52: } 53: } 54: ); 55: } 56: }); 57: }); 58: } 59: } 60: }); 61: } 62: }); 63: }); Run it locally and now we can find the response was sent after all entities had been inserted. Query entities against table service is simple as well. Just use the “queryEntity” method from the table service client and providing the partition key and row key. We can also provide a complex query criteria as well, for example the code here. In the code below I queried an entity by the partition key and row key, and return the proper localization value in response. 1: app.get("/was/:key/:culture", function (req, res) { 2: var key = req.params.key; 3: var culture = req.params.culture; 4: client.queryEntity(tableName, culture, key, function (error, entity) { 5: if (error) { 6: res.send(500, error); 7: } 8: else { 9: res.json(entity); 10: } 11: }); 12: }); And then tested it on local emulator. Finally if we want to publish this application to the cloud we should change the database connection string and storage account. For more information about how to consume blob and queue service, as well as the service bus please refer to the MSDN page.   Consume Service Runtime As I mentioned above, before we published our application to the cloud we need to change the connection string and account information in our code. But if you had played with WACS you should have known that the service runtime provides the ability to retrieve configuration settings, endpoints and local resource information at runtime. Which means we can have these values defined in CSCFG and CSDEF files and then the runtime should be able to retrieve the proper values. For example we can add some role settings though the property window of the role, specify the connection string and storage account for cloud and local. And the can also use the endpoint which defined in role environment to our Node.js application. In Node.js SDK we can get an object from “azure.RoleEnvironment”, which provides the functionalities to retrieve the configuration settings and endpoints, etc.. In the code below I defined the connection string variants and then use the SDK to retrieve and initialize the table client. 1: var connectionString = ""; 2: var storageAccountName = ""; 3: var storageAccountKey = ""; 4: var tableName = ""; 5: var client; 6:  7: azure.RoleEnvironment.getConfigurationSettings(function (error, settings) { 8: if (error) { 9: console.log("ERROR: getConfigurationSettings"); 10: console.log(JSON.stringify(error)); 11: } 12: else { 13: console.log(JSON.stringify(settings)); 14: connectionString = settings["SqlConnectionString"]; 15: storageAccountName = settings["StorageAccountName"]; 16: storageAccountKey = settings["StorageAccountKey"]; 17: tableName = settings["TableName"]; 18:  19: console.log("connectionString = %s", connectionString); 20: console.log("storageAccountName = %s", storageAccountName); 21: console.log("storageAccountKey = %s", storageAccountKey); 22: console.log("tableName = %s", tableName); 23:  24: client = azure.createTableService(storageAccountName, storageAccountKey); 25: } 26: }); In this way we don’t need to amend the code for the configurations between local and cloud environment since the service runtime will take care of it. At the end of the code we will listen the application on the port retrieved from SDK as well. 1: azure.RoleEnvironment.getCurrentRoleInstance(function (error, instance) { 2: if (error) { 3: console.log("ERROR: getCurrentRoleInstance"); 4: console.log(JSON.stringify(error)); 5: } 6: else { 7: console.log(JSON.stringify(instance)); 8: if (instance["endpoints"] && instance["endpoints"]["nodejs"]) { 9: var endpoint = instance["endpoints"]["nodejs"]; 10: app.listen(endpoint["port"]); 11: } 12: else { 13: app.listen(8080); 14: } 15: } 16: }); But if we tested the application right now we will find that it cannot retrieve any values from service runtime. This is because by default, the entry point of this role was defined to the worker role class. In windows azure environment the service runtime will open a named pipeline to the entry point instance, so that it can connect to the runtime and retrieve values. But in this case, since the entry point was worker role and the Node.js was opened inside the role, the named pipeline was established between our worker role class and service runtime, so our Node.js application cannot use it. To fix this problem we need to open the CSDEF file under the azure project, add a new element named Runtime. Then add an element named EntryPoint which specify the Node.js command line. So that the Node.js application will have the connection to service runtime, then it’s able to read the configurations. Start the Node.js at local emulator we can find it retrieved the connections, storage account for local. And if we publish our application to azure then it works with WASD and storage service through the configurations for cloud.   Summary In this post I demonstrated how to use Windows Azure SDK for Node.js to interact with storage service, especially the table service. I also demonstrated on how to use WACS service runtime, how to retrieve the configuration settings and the endpoint information. And in order to make the service runtime available to my Node.js application I need to create an entry point element in CSDEF file and set “node.exe” as the entry point. I used five posts to introduce and demonstrate on how to run a Node.js application on Windows platform, how to use Windows Azure Web Site and Windows Azure Cloud Service worker role to host our Node.js application. I also described how to work with other services provided by Windows Azure platform through Windows Azure SDK for Node.js. Node.js is a very new and young network application platform. But since it’s very simple and easy to learn and deploy, as well as, it utilizes single thread non-blocking IO model, Node.js became more and more popular on web application and web service development especially for those IO sensitive projects. And as Node.js is very good at scaling-out, it’s more useful on cloud computing platform. Use Node.js on Windows platform is new, too. The modules for SQL database and Windows Azure SDK are still under development and enhancement. It doesn’t support SQL parameter in “node-sqlserver”. It does support using storage connection string to create the storage client in “azure”. But Microsoft is working on make them easier to use, working on add more features and functionalities.   PS, you can download the source code here. You can download the source code of my “Copy all always” tool here.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• The Definitive C++ Book Guide and List

  - by grepsedawk

  After more than a few questions about deciding on C++ books I thought we could make a better community wiki version. Providing QUALITY books and an approximate skill level. Maybe we can add a short blurb/description about each book that you have personally read / benefited from. Feel free to debate quality, headings, etc. Note: There is a similar post for C: The Definitive C Book Guide and List Reference Style - All Levels The C++ Programming Language - Bjarne Stroustrup C++ Standard Library Tutorial and Reference - Nicolai Josuttis Beginner Introductory: C++ Primer - Stanley Lippman / Josée Lajoie / Barbara E. Moo Accelerated C++ - Andrew Koenig / Barbara Moo Thinking in C++ - Bruce Eckel (2 volumes, 2nd is more about standard library, but still very good) Best practices: Effective C++ - Scott Meyers Effective STL - Scott Meyers Intermediate More Effective C++ - Scott Meyers Exceptional C++ - Herb Sutter More Exceptional C++ - Herb Sutter C++ Coding Standards: 101 Rules, Guidelines, and Best Practices - Herb Sutter / Andrei Alexandrescu C++ Templates The Complete Guide - David Vandevoorde / Nicolai M. Josuttis Large Scale C++ Software Design - John Lakos Above Intermediate Modern C++ Design - Andrei Alexandrescu C++ Template Metaprogramming - David Abrahams and Aleksey Gurtovoy Inside the C++ Object Model - Stanley Lippman Classics / Older Note: Some information contained within these books may not be up to date and no longer considered best practice. The Design and Evolution of C++ - Bjarne Stroustrup Ruminations on C++ Andrew Koenig / Barbara Moo Advanced C++ Programming Styles and Idioms - James Coplien

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• Play audio file data - Spring MVC

  - by Vijay Veeraraghavan

  In my web-application, I have various audio clips uploaded by the users in the database stored in the BLOB column. The audio files are low bit rate WAV files. The clips are secured, one can see only those clips he has uploaded. Instead of user downloading the clip and playing it in his player, I need it be steamed online in the web page itself. In the jsp I use the <audio> tag with the source mapping to the controller mappping url. <td> <audio controls><source src="recfile/${au.id}" type="audio/mpeg" /></audio> </td> Where, the recfile is the request mapping and the au.id is the audio id. In the controller I process the request like below @RequestMapping(value = "/recfile/{id}", method = RequestMethod.GET, produces = { MediaType.APPLICATION_OCTET_STREAM_VALUE }) public HttpEntity<byte[]> downloadRecipientFile(@PathVariable("id") int id, ModelMap model, HttpServletResponse response) throws IOException, ServletException { LOGGER.debug("[GroupListController downloadRecipientFile]"); VoiceAudioLibrary dGroup = audioClipService.findAudioClip(id); if (dGroup == null || dGroup.getAudioData() == null || dGroup.getAudioData().length <= 0) { throw new ServletException("No clip found/clip has not data, id=" + id); } HttpHeaders header = new HttpHeaders(); I tried this too //header.setContentType(new MediaType("audio", "mp3")); header.setContentType(new MediaType("audio", "vnd.wave"); header.setContentLength(dGroup.getAudioData().length); return new HttpEntity<byte[]>(dGroup.getAudioData(), header); } When the jsp loads, the controller get the request, it serves back the audio data fetched from the database, the jsp too shows the player with the controls. But when I play it nothing happens. Why is it? Am I missing anything in the configuration? Am I doing it right?

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• KnpLabs / DoctrineBehaviors Translatable - currentLocale = null

  - by Ruben

  Using the trait \Knp\DoctrineBehaviors\Model\Translatable\Translation inside an Entity, I see that the property currentLocale is never setted , so we always obtain the default locale ('en') in all the calls to $this->translate(). If I change this getDefaultLocale, all the translations are made correctly, so I think that is no problem with the fallback. I tried debug the currentLocaleCallable. I see that if I put a "var_dump ($this-container-get('request'));" in the contructor of currentLocaleCallable, the request have a locale to null. And outside the request has the correct locale.It seems that container is not in the scope: request , i don't know how can I get it to work I post an issue in github https://github.com/KnpLabs/DoctrineBehaviors/issues/71 EDITED This service is defined in vendor/knplabs/doctrine-behaviors/config/orm-services.yml and is: knp.doctrine_behaviors.reflection.class_analyzer: class: "%knp.doctrine_behaviors.reflection.class_analyzer.class%" public: false knp.doctrine_behaviors.translatable_listener: class: "%knp.doctrine_behaviors.translatable_listener.class%" public: false arguments: - "@knp.doctrine_behaviors.reflection.class_analyzer" - "%knp.doctrine_behaviors.reflection.is_recursive%" - "@knp.doctrine_behaviors.translatable_listener.current_locale_callable" tags: - { name: doctrine.event_subscriber } knp.doctrine_behaviors.translatable_listener.current_locale_callable: class: "%knp.doctrine_behaviors.translatable_listener.current_locale_callable.class%" arguments: - "@service_container" # lazy request resolution public: false EDIT 2: My composer.json "php": ">=5.3.3", "symfony/symfony": "2.3.*", "doctrine/orm": ">=2.2.3,<2.4-dev", "doctrine/doctrine-bundle": "1.2.*", "twig/extensions": "1.0.*", "symfony/assetic-bundle": "2.3.*", "symfony/swiftmailer-bundle": "2.3.*", "symfony/monolog-bundle": "2.3.*", "sensio/distribution-bundle": "2.3.*", "sensio/framework-extra-bundle": "2.3.*", "sensio/generator-bundle": "2.3.*", "incenteev/composer-parameter-handler": "~2.0", "friendsofsymfony/user-bundle": "1.3.*", "avalanche123/imagine-bundle": "v2.1", "raulfraile/ladybug-bundle": "~1.0", "genemu/form-bundle": "2.2.*", "friendsofsymfony/rest-bundle": "0.12.0", "stof/doctrine-extensions-bundle": "dev-master", "sonata-project/admin-bundle": "dev-master", "a2lix/translation-form-bundle": "1.*@dev", "sonata-project/user-bundle": "dev-master", "psliwa/pdf-bundle": "dev-master", "jms/serializer-bundle": "dev-master", "jms/di-extra-bundle": "dev-master", "knplabs/doctrine-behaviors": "dev-master", "sonata-project/doctrine-orm-admin-bundle": "dev-master", "knplabs/knp-paginator-bundle": "dev-master", "friendsofsymfony/jsrouting-bundle": "~1.1", "zendframework/zend-validator": ">=2.0.0-rc2", "zendframework/zend-barcode": ">=2.0.0-rc2"

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• Socket.ReceiveAsync problem

  - by bartol

  Hi, I have a problem using SocketAsyncEventArgs model with .net sockets. Everything works great until the moment that the server wishes to close a client connection. I use following code for this: try { socket.Shutdown(SocketShutdown.Both); } catch { } // throws if client process has already closed finally { socket.Close(); } socket = null; Each connection is using two SocketAsyncEventArgs (one for send and one for receive) and after closing the connection they are returned to a pool from which they can be later reused. And here the problem starts, because when another connection is established and receive args are reused from the pool we get an exception: System.InvalidOperationException: "An asynchronous socket operation is already in progress using this SocketAsyncEventArgs instance."; at System.Net.Sockets.SocketAsyncEventArgs.StartOperationCommon(Socket socket) at System.Net.Sockets.Socket.ReceiveAsync(SocketAsyncEventArgs e) I've done some debugging and it appears that the connection closing code from the beginning of the question does not cancel Socket.ReceiveAsync operation that is in progress when the connection is closed. I've tried many combinations of Shutdown, Disconnect and Linger options for the socket but nothing worked. Any suggestions? Thanks

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• RIA Services EntitySet does not support 'Edit' opperation

  - by Savvas Sopiadis

  Hello everbody! Making my first steps in RIA Services (VS2010Beta2) and i encountered this problem: created an EF Model (no POCOs), generic repository on top of it and a RIA Service(hosted in an ASP.NET MVC application) and tryed to get data from within the ASP.NET MVC application: worked well. Next step: Silverlight client. Got a reference to the RIAService (through its context), queried for all the records of the repository and got them into the SL application as well (using this code sample): private ObservableCollection<Culture> _cultures = new ObservableCollection<Culture>(); public ObservableCollection<Culture> cultures { get { return _cultures; } set { _cultures = value; RaisePropertyChanged("cultures"); } } .... //Get cultures EntityQuery<Culture> queryCultures = from cu in dsCtxt.GetAllCulturesQuery() select cu; loCultures = dsCtxt.Load(queryCultures); loCultures.Completed += new EventHandler(lo_Completed); .... void loAnyCulture_Completed(object sender, EventArgs e) { ObservableCollection<Culture> temp= new ObservableCollection<Culture>loAnyCulture.Entities); AnyCulture = temp[0]; } The problem is this: whenever i try to edit some data of a record (in this example the first record) i get this error: This EntitySet of type 'Culture' does not support the 'Edit' operation. I thought that i did something weird and tryed to create an object of type Culture and assign a value to it: it worked well! What am i missing? Do i have to declare an EntitySet? Do i have to mark it? Do i have to...what? Thanks in advance

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• WPF MVVM UserControl Binding "Container", dispose to avoid memory leak.

  - by user178657

  For simplicity. I have a window, with a bindable usercontrol <UserControl Content="{Binding Path = BindingControl, UpdateSourceTrigger=PropertyChanged}"> I have two user controls, ControlA, and ControlB, Both UserControls have their own Datacontext ViewModel, ControlAViewModel and ControlBViewModel. Both ControlAViewModel and ControlBViewModel inh. from a "ViewModelBase" public abstract class ViewModelBase : DependencyObject, INotifyPropertyChanged, IDisposable........ Main window was added to IoC... To set the property of the Bindable UC, i do ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlA; ControlA, in its Datacontext, creates a DispatcherTimer, to do "somestuff".. Later on., I need to navigate elsewhere, so the other usercontrol is loaded into the container ComponentRepository.Resolve<MainViewWindow>().Bindingcontrol= new ControlB If i put a break point in the "someStuff" that was in ControlA's datacontext. The DispatcherTimer is still running... i.e. loading a new usercontrol into the bindable Usercontrol on mainwindow does not dispose/close/GC the DispatcherTimer that was created in the DataContext View Model... Ive looked around, and as stated by others, dispose doesnt get called because its not supposed to... :) Not all my usercontrols have DispatcherTimer, just a few that need to do some sort of "read and refresh" updates./. Should i track these DispatcherTimer objects in the ViewModelBase that all Usercontrols inh. and manually stop/dispose them everytime a new usercontrol is loaded? Is there a better way?

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• Column Header for a WPF TreeView

  - by nareshbhatia

  I am using the WPF TreeView to display some hierarchical information. Each item in the TreeView consists of several attributes, so I am using a Grid within my HierarchicalDataTemplate to display these attributes: <HierarchicalDataTemplate x:Key="ArtistTemplate" ItemsSource="{Binding XPath=Title}" ItemTemplate="{StaticResource TitleTemplate}"> <Grid> <Grid.ColumnDefinitions> <ColumnDefinition SharedSizeGroup="NameColumn" /> <ColumnDefinition SharedSizeGroup="GenreColumn" /> <ColumnDefinition SharedSizeGroup="BornColumn" /> <ColumnDefinition SharedSizeGroup="DiedColumn" /> </Grid.ColumnDefinitions> <TextBlock Grid.Column="0" Text="{Binding XPath=@Name}" /> <TextBlock Grid.Column="1" Text="{Binding XPath=@Genre}" /> <TextBlock Grid.Column="2" Text="{Binding XPath=@Born}" /> <TextBlock Grid.Column="3" Text="{Binding XPath=@Died}" /> </Grid> </HierarchicalDataTemplate> This displays as a nice TreeView with 4 columns - so far so good! The only additional thing I need is a header above the TreeView that displays column names. The header column widths should be synchronized with TreeViewItems and also the header styles should be customizable. What's the easiest way to do this? P.S. I found two solutions that came close: 1) A TreeListView here, but this requires me to implement a custom interface (ITreeModel) to my model. Also the approach in this solution is to start with a ListView and to implement a RowExpander manually. In my case, the TreeView is sufficiently close to what I need, so I am hoping that putting a header on it should be very simple. 2) A TreeListView here. This one indeed starts with a TreeView, but I can't figure out how to customize the header. I suspect that I have to customize the GridViewHeaderRowPresenter in the generic.xaml, but this element does not seem to have its own ControlTemplate.

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• Entity Framework - adding new items via a navigation property

  - by Robert

  I have come across what appears to be very peculiar behaviour using entity framework 4.0. I have a User entity, which has a Company (A Company has many Users). If I do this, everything works as expected and I get a nice shiny new user in the database: var company = _model.Companies.First(); company.Users.Add(new User(1, "John", "Smith")); _model.SaveChanges(); However, if I do this, then I get nothing new in the database, and no exceptions thrown: var existingUser = _model.Users.First(); var company = existingUser.Company; company.Users.Add(new User(1, "John", "Smith")); _model.SaveChanges(); So it appears that if I add a User to the Company that is pulled directly from the model, then everything works fine. However if the User is added to a Company that is pulled as a navigation property of another object, then it doesn't work. Can someone tell me if this is expected behaviour, or if there is something I can do to make it so that it is? Thanks!

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• Why LINQ to Entities won't let me initialize just some properties of an Entity?

  - by emzero

  So I've started to add Entity Framework 4 into a legacy web application (ASP.NET WebForms). As a start I have auto-generated some entities from the database. Also I want to apply Repository Pattern. There is an entity called Visitor and its repository VisitorRepository In VisitorRepository I have the following method: public IEnumerable<Visitor> GetActiveVisitors() { var visitors = from v in _context.Visitors where v.IsActive select new Visitor { VisitorID = v.VisitorID, EmailAddress = v.EmailAddress, RegisterDate = v.RegisterDate, Company = v.Company, Position = v.Position, FirstName = v.FirstName, LastName = v.LastName }; return visitors.ToList(); } That List is then bound to a repeater and when trying to do <%# Eval('EmailAddress') #%> it throws the following exception. The entity or complex type 'Model.Visitor' cannot be constructed in a LINQ to Entities query. A) Why is this happening? How I can workaround this? Do I need to select an anonymous type and then use that to initialize my entities??? B) Why every example I've seen makes use of 'select new' (anonymous object) instead of initializing a known type? Anonymous types are useless unless you are retrieving the data and showing it in the same layer. As far as I know anonymous types cannot be returned from methods? So what's the real point of them??? Thank you all

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• Asp.net MVC ModelState.Clear

  - by Mr Grok

  Can anyone give me a succinct definition of the role of ModelState in Asp.net MVC (or a link to one). In particular I need to know in what situations it is necessary or desirable to call ModelState.Clear(). Can anyone give me a succinct definition of the role of ModelState in Asp.net MVC (or a link to one). In particular I need to know in what situations it is necessary or desirable to call ModelState.Clear(). Bit open ended huh... sorry, I think it might help if tell you what I'm acutally doing: I have an Action of Edit on a Controller called "Page". When I first see the form to change the Page's details everything loads up fine (binding to a "MyCmsPage" object). Then I click a button that generates a value for one of the MyCmsPage object's fields (MyCmsPage.SeoTitle). It generates fine and updates the object and I then return the action result with the newly modified page object and expect the relevant textbox (rendered using <%= Html.TextBox("seoTitle", page.SeoTitle)%) to be updated ... but alas it displays the value from the old model that was loaded. I've worked around it by using ModelState.Clear() but I need to know why / how it has worked so I'm not just doing it blindly. PageController: [AcceptVerbs("POST")] public ActionResult Edit(MyCmsPage page, string submitButton) { // add the seoTitle to the current page object page.GenerateSeoTitle(); // why must I do this? ModelState.Clear(); // return the modified page object return View(page); } Aspx: <%@ Page Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<MyCmsPage>" %> .... <div class="c"> <label for="seoTitle"> Seo Title</label> <%= Html.TextBox("seoTitle", page.SeoTitle)%> <input type="submit" value="Generate Seo Title" name="submitButton" /> </div>

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• Implementing the double-click event on Silverlight 4 Datagrid

  - by Mohammed Mudassir Azeemi

  Any good soul have an example of implementing the "Command Pattern" introduced by Prism on "Double-click event" of Silverlight 4.0 DataGrid. I did try the following: <data:DataGrid x:Name="dgUserRoles" AutoGenerateColumns="False" Margin="0" Grid.Row="0" ItemsSource="{Binding Path=SelectedUser.UserRoles}" IsReadOnly="False" > <data:DataGrid.Columns> <data:DataGridTemplateColumn Header=" "> <data:DataGridTemplateColumn.CellTemplate> <DataTemplate> <Button Width="20" Height="20" Click="Button_Click" Command="{Binding EditRoleClickedCommand}" CommandParameter="{Binding SelectedRole}" > </Button> </DataTemplate> </data:DataGridTemplateColumn.CellTemplate> </data:DataGridTemplateColumn> <data:DataGridTextColumn Header="Role Name" Binding="{Binding RoleName}" /> <data:DataGridTextColumn Header="Role Code" Binding="{Binding UserroleCode}" IsReadOnly="True"/> <data:DataGridCheckBoxColumn Header="UDFM Managed" Binding="{Binding RoleIsManaged}" IsReadOnly="True" /> <data:DataGridCheckBoxColumn Header="UDFM Role Assigned" Binding="{Binding UserroleIsUdfmRoleAssignment}" IsReadOnly="True" /> <data:DataGridTextColumn Header="Source User" Binding="{Binding SourceUser}" IsReadOnly="True" /> </data:DataGrid.Columns> </data:DataGrid> As you see I did try to hook up the Command there and it is not firing the event in my View Model. Looking for a good alternative.

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• Any alternative to hide querystring from Html.actionlink on ASP.NET MVC Page?

  - by Madhavi

  Hi I have a page called SearchDcouments.aspx that displays all the matching documents as Hyperlinks in the table format as below. When the User clicks on any particular document, the sample url will be: http://localhost:52483/Home/ShowDocument?docID=280 So that the DocumentID is passed as Querystring to the ControllerMethod ShowDocument and the ID is visible in the URL. Now for Security purposes, I want to hide this way of passing the Querystring parameters. Wondering what are the alternatives to hide the DocID from the URL? Appreciate your responses. Thanks Code in the View: <tbody> <% foreach (var item in Model){ %> <tr> <% string actionTitle = item.DocumentType.ToLower() == "letter" ? "Request References" : "Request Slides"; %> <td> <%= Html.ActionLink(actionTitle, MVC.Home.ShowDocument(item.DocumentID))%> </td> </tr> <% } %> </tbody> Code in the Controller: [Authorize] [HttpGet] public virtual ActionResult ShowDocument(int docID) { Document document = miEntity.GetDocumentByID(docID); switch (document.DocType.ToLower()) { case "slide": SlideRequestViewModel slide = new SlideRequestViewModel(docID); return View(MVC.Home.Views.ShowSlideRequest, slide); case "letter": RefRequestViewModel rrq = new RefRequestViewModel(docID); return DoShowRefRequest(rrq); default: break; } // Here - let's get back home return RedirectToAction(MVC.Home.Default()); }

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• Cannot convert lambda expression to type 'string' because it is not a delegate type

  - by RememberME

  I have the following code written by another developer on 2 pages of my site. This used to work just fine, but now is giving the error "Cannot convert lambda expression to type 'string' because it is not a delegate type" on the Delete line with Ajax.ThemeRollerActionLink. I don't go into this section of the site often, and we recently upgraded from MVC 1.0 to 2.0. I'm guessing that's probably when it stopped working. I've looked up this error and the recommended fix seems to be add using System.Linq However, the page already has <%@ Import Namespace="System.Linq" %> <% Html.Grid(Model).Columns(col => { col.For(c => "<a href='" + Url.Action("Edit", new { userName = c }) + "' class=\"fg-button fg-button-icon-solo ui-state-default ui-corner-all\"><span class=\"ui-icon ui-icon-pencil\"></span></a>").Named("Edit").DoNotEncode(); col.For(c => Ajax.ThemeRollerActionLink("fg-button fg-button-icon-solo ui-state-default ui-corner-all", "ui-icon ui-icon-close", "Delete", new { userName = c }, new AjaxOptions { Confirm = "Delete User?", HttpMethod = "Delete", InsertionMode = InsertionMode.Replace, UpdateTargetId = "gridcontainer", OnSuccess = "successDeleteAssignment", OnFailure = "failureDeleteAssignment" })).Named("Delete").DoNotEncode(); col.For(c => c).Named("User"); }).Attributes(id => "userlist").Render(); %>

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• asp.net mvc radioButtonFor in forEach

  - by George

  Does anyone know why this isn't working? any source code changes would be great. <% foreach (var i in Model.talentImages) { %> <div style="padding:15px;"> <img src="<%: i.uri %>" width="95" height="84" alt="" style="float:left; padding:0px 20px 0px 0px" /> <div style="padding:30px 10px 10px 10px"> <%: Html.RadioButtonFor("group-" + i.uriId.ToString(), i.isApproved)%> Approved <br /> <%: Html.RadioButtonFor("group-" + i.uriId.ToString(), i.isApproved)%> Deny <br /> </div> <hr width="0"/> <%= Html.RadioButton("isProfileePicGroup", i.isProfilePic, false)%> Make Profile Picture <br /> </div> <hr /> <%} %>

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• DataBinding a dictionary to a combobox in WPF.

  - by Ashish Ashu

  I have a Dictionary which is binded to a combobox. I have used dictionary to provide spaces in enum. public enum Option {Enter_Value, Select_Value}; Dictionary<Option,string> Options; <ComboBox x:Name="optionComboBox" SelectionChanged="optionComboBox_SelectionChanged" SelectedValuePath="Key" DisplayMemberPath="Value" SelectedItem="{Binding Path = SelectedOption}" ItemsSource="{Binding Path = Options}" /> This works fine. My queries: 1. I am not able to set the initial value to a combo box. In above XAML snippet the line SelectedItem="{Binding Path = SelectedOption}" is not working. I have declared SelectOption in my viewmodel. This is of type string and I have intialized this string value in my view model as below: SelectedOption = Options[Options.Enter_Value].ToString(); 2. I want if user selects Options.Enter_Value from the combo box , the combo box becomes editable and user can enter the numeric value in it. If user selects the second option Options.Select_Value then a dialog is poped up which allows user to select the predifined values. And the combo box becomes read only and shows the selected value. Please Help!!

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• Send large JSON data to WCF Rest Service

  - by Christo Fur

  Hi I have a client web page that is sending a large json object to a proxy service on the same domain as the web page. The proxy (an ashx handler) then forwards the request to a WCF Rest Service. Using a WebClient object (standard .net object for making a http request) The JSON successfully arrives at the proxy via a jQuery POST on the client webpage. However, when the proxy forwards this to the WCF service I get a Bad Request - Error 400 This doesn't happen when the size of the json data is small The WCF service contract looks like this [WebInvoke(Method = "POST", BodyStyle = WebMessageBodyStyle.Wrapped, RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json)] [OperationContract] CarConfiguration CreateConfiguration(CarConfiguration configuration); And the DataContract like this [DataContract(Namespace = "")] public class CarConfiguration { [DataMember(Order = 1)] public int CarConfigurationId { get; set; } [DataMember(Order = 2)] public int UserId { get; set; } [DataMember(Order = 3)] public string Model { get; set; } [DataMember(Order = 4)] public string Colour { get; set; } [DataMember(Order = 5)] public string Trim { get; set; } [DataMember(Order = 6)] public string ThumbnailByteData { get; set; } [DataMember(Order = 6)] public string Wheel { get; set; } [DataMember(Order = 7)] public DateTime Date { get; set; } [DataMember(Order = 8)] public List<string> Accessories { get; set; } [DataMember(Order = 9)] public string Vehicle { get; set; } [DataMember(Order = 10)] public Decimal Price { get; set; } } When the ThumbnailByteData field is small, all is OK. When it is large I get the 400 error What are my options here? I've tried increasing the MaxBytesRecived config setting but that is not enough Any ideas?

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• AllowPartiallyTrustedCallersAttribute exception - unit testing with moq

  - by vdh_ant

  Hi guys I am receiving the following exception when trying to run my unit tests using .net 4.0 under VS2010 with moq 3.1. Attempt by security transparent method 'SPPD.Backend.DataAccess.Test.Specs_for_Core.When_using_base.Can_create_mapper()' to access security critical method 'Microsoft.VisualStudio.TestTools.UnitTesting.Assert.IsNotNull(System.Object)' failed. Assembly 'SPPD.Backend.DataAccess.Test, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null' is marked with the AllowPartiallyTrustedCallersAttribute, and uses the level 2 security transparency model. Level 2 transparency causes all methods in AllowPartiallyTrustedCallers assemblies to become security transparent by default, which may be the cause of this exception. The test I am running is really straight forward and looks something like the following: [TestMethod] public void Can_create_mapper() { this.SetupTest(); var mockMapper = new Moq.Mock<IMapper>().Object; this._Resolver.Setup(x => x.Resolve<IMapper>()).Returns(mockMapper).Verifiable(); var testBaseDa = new TestBaseDa(); var result = testBaseDa.TestCreateMapper<IMapper>(); Assert.IsNotNull(result); //<<< THROWS EXCEPTION HERE Assert.AreSame(mockMapper, result); this._Resolver.Verify(); } I have no idea what this means and I have been looking around and have found very little on the topic. The closest reference I have found is this http://dotnetzip.codeplex.com/Thread/View.aspx?ThreadId=80274 but its not very clear on what they did to fix it... Anyone got any ideas?

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• How to use multiple DisplayName attribute using Entity Framework and ASP.Net Mvc 2

  - by Picflight

  Depending on where I use my Class, I want to be able to show a different DisplayName. I have the following class: [MetadataType(typeof(PortalMetaData))] [System.Web.Mvc.Bind(Exclude = "PortalId")] public partial class Portal { public Portal() { this.Created = DateTime.Now; } } public class PortalMetaData { [Required(ErrorMessage = "Portal name is required")] [StringLength(50, ErrorMessage = "Portal name must be under 50 characters")] public object PortalName { get; set; } [Required(ErrorMessage = "Description is required")] public object Description { get; set; } } I have a corresponding Table in the database Portal I use the Portal table with a PortalController for the Site Admin to update the records in the Portal Table. I want another user with a different Role (AsstAdmin) to be able to update this table as well. To facilitate that I am thinking of creating a separate partial class that somehow links back to the Portal Model. This would allow me to display limited Fields for update by the AsstAdmin and I can display a different name for the Field as well. How can I accomplish this task? If I add the following class which inherits from Portal than I get an exception: Unable to cast object of type 'Project1.Mvc.Models.Portal' to type 'Prpject1.Mvc.Models.Site'. [MetadataType(typeof(SiteMetaData))] public class Site : Portal { public Site() { } } public class SiteMetaData { [Required(DisplayName = "Site Description")] public object Description { get; set; } }

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• managing images in an iphone/ipad universal app

  - by taber

  Hi, I'm just curious as to what methods people are using to dynamically use larger or smaller images in their universal iPhone/iPad apps. I created a large test image and I tried scaling down (using cocos2d) by 0.46875. After viewing that in the iPhone 4.0 simulator I found the results were pretty crappy... rough pixel edges, etc. Plus, loading huge image files for iPhone users when they don't need them is pretty lame. So I guess what I will probably have to do is save out two versions of every sprite... large (for the iPad side) and small (for iPhone/iPod Touch) then detect the user's device and spit out the proper sprite like so: NSString *deviceType = [UIDevice currentDevice].model; CCSprite *test; if([deviceType isEqualToString:@"iPad"]) { test = [CCSprite spriteWithFile:@"testBigHuge.png"]; } else { test = [CCSprite spriteWithFile:@"testRegularMcTiny.png"]; } [self addChild: test]; How are you guys doing this? I'd rather avoid sprinkling all of my code with if statements like this. I want to also avoid using .xib files since it's an OpenGL-based app. Thanks!

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• JavaScriptSerializer().Serialize(Entity Framework object)

  - by loviji

  May be, it is not so problematic for you. but i'm trying first time with json serialization. and also read other articles in stackowerflow. I have created Entity Framework data model. then by method get all data from object: private uqsEntities _db = new uqsEntities(); //get all data from table sysMainTableColumns where tableName=paramtableName public List<sysMainTableColumns> getDataAboutMainTable(string tableName) { return (from column in _db.sysMainTableColumns where column.TableName==tableName select column).ToList(); } my webservice: public string getDataAboutMainTable() { penta.DAC.Tables dictTable = new penta.DAC.Tables(); var result = dictTable.getDataAboutMainTable("1"); return new JavaScriptSerializer().Serialize(result); } and jQuery ajax method $('#loadData').click(function() { $.ajax({ type: "POST", url: "WS/ConstructorWS.asmx/getDataAboutMainTable", data: "{}", contentType: "application/json; charset=utf-8", dataType: "json", success: function(msg) { $("#jsonResponse").html(msg); var data = eval("(" + msg + ")"); //do something with data }, error: function(msg) { } }); }); problem with data, code fails there. and i think i'm not use JavaScriptSerializer().Serialize() method very well. Please, tell me, what a big mistake I made in C# code?

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• Can plugins loaded with MEF resolve their own internal dependencies with the same MEF container for

  - by Dave

  From my experimentation, I think the answer is "kind of", but I could have made a mistake. I have an application that loads appliance plugins with MEF. That part is working fine. Now let's say that my BlenderAppliance wants to resolve several of its dependencies with MEF, which each implement IApplianceFeature. I've just used the ImportMany attribute to my plugin. I made sure to create the plugin using MEF so that the Imports work properly. I said "kind of" because some of the plugin's internals (i.e. the model) are loading with MEF just fine, but the IApplianceFeatures aren't. The difference here is that the IApplianceFeatures are themselves, assemblies. And at the moment, they are in one folder above that of the plugin itself, i.e. + application folder | IApplianceFeature1.dll | IApplianceFeature2.dll +---+ plugin folder | BlenderAppliance.dll Now if my application uses an AggregateCatalog to load the "." and ".\plugins" folders, why doesn't it ever load the IApplianceFeature assemblies for me? Is it possible / advisable to have the plugin create its own MEF container to resolve its dependencies, or does really nasty stuff happen? If you have any stories about this scenario, please share. :)

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