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• The Incremental Architect&acute;s Napkin - #1 - It&acute;s about the money, stupid

  - by Ralf Westphal

  Originally posted on: http://geekswithblogs.net/theArchitectsNapkin/archive/2014/05/24/the-incremental-architectacutes-napkin---1---itacutes-about-the.aspx Software development is an economic endeavor. A customer is only willing to pay for value. What makes a software valuable is required to become a trait of the software. We as software developers thus need to understand and then find a way to implement requirements. Whether or in how far a customer really can know beforehand what´s going to be valuable for him/her in the end is a topic of constant debate. Some aspects of the requirements might be less foggy than others. Sometimes the customer does not know what he/she wants. Sometimes he/she´s certain to want something - but then is not happy when that´s delivered. Nevertheless requirements exist. And developers will only be paid if they deliver value. So we better focus on doing that. Although is might sound trivial I think it´s important to state the corollary: We need to be able to trace anything we do as developers back to some requirement. You decide to use Go as the implementation language? Well, what´s the customer´s requirement this decision is linked to? You decide to use WPF as the GUI technology? What´s the customer´s requirement? You decide in favor of a layered architecture? What´s the customer´s requirement? You decide to put code in three classes instead of just one? What´s the customer´s requirement behind that? You decide to use MongoDB over MySql? What´s the customer´s requirement behind that? etc. I´m not saying any of these decisions are wrong. I´m just saying whatever you decide be clear about the requirement that´s driving your decision. You have to be able to answer the question: Why do you think will X deliver more value to the customer than the alternatives? Customers are not interested in romantic ideals of hard working, good willing, quality focused craftsmen. They don´t care how and why you work - as long as what you deliver fulfills their needs. They want to trust you to recognize this as your top priority - and then deliver. That´s all. Fundamental aspects of requirements If you´re like me you´re probably not used to such scrutinization. You want to be trusted as a professional developer - and decide quite a few things following your gut feeling. Or by relying on “established practices”. That´s ok in general and most of the time - but still… I think we should be more conscious about our decisions. Which would make us more responsible, even more professional. But without further guidance it´s hard to reason about many of the myriad decisions we´ve to make over the course of a software project. What I found helpful in this situation is structuring requirements into fundamental aspects. Instead of one large heap of requirements then there are smaller blobs. With them it´s easier to check if a decisions falls in their scope. Sure, every project has it´s very own requirements. But all of them belong to just three different major categories, I think. Any requirement either pertains to functionality, non-functional aspects or sustainability. For short I call those aspects: Functionality, because such requirements describe which transformations a software should offer. For example: A calculator software should be able to add and multiply real numbers. An auction website should enable you to set up an auction anytime or to find auctions to bid for. Quality, because such requirements describe how functionality is supposed to work, e.g. fast or secure. For example: A calculator should be able to calculate the sinus of a value much faster than you could in your head. An auction website should accept bids from millions of users. Security of Investment, because functionality and quality need not just be delivered in any way. It´s important to the customer to get them quickly - and not only today but over the course of several years. This aspect introduces time into the “requrements equation”. Security of Investments (SoI) sure is a non-functional requirement. But I think it´s important to not subsume it under the Quality (Q) aspect. That´s because SoI has quite special properties. For one, SoI for software means something completely different from what it means for hardware. If you buy hardware (a car, a hair blower) you find that a worthwhile investment, if the hardware does not change it´s functionality or quality over time. A car still running smoothly with hardly any rust spots after 10 years of daily usage would be a very secure investment. So for hardware (or material products, if you like) “unchangeability” (in the face of usage) is desirable. With software you want the contrary. Software that cannot be changed is a waste. SoI for software means “changeability”. You want to be sure that the software you buy/order today can be changed, adapted, improved over an unforseeable number of years so as fit changes in its usage environment. But that´s not the only reason why the SoI aspect is special. On top of changeability[1] (or evolvability) comes immeasurability. Evolvability cannot readily be measured by counting something. Whether the changeability is as high as the customer wants it, cannot be determined by looking at metrics like Lines of Code or Cyclomatic Complexity or Afferent Coupling. They may give a hint… but they are far, far from precise. That´s because of the nature of changeability. It´s different from performance or scalability. Also it´s because a customer cannot tell upfront, “how much” evolvability he/she wants. Whether requirements regarding Functionality (F) and Q have been met, a customer can tell you very quickly and very precisely. A calculation is missing, the calculation takes too long, the calculation time degrades with increased load, the calculation is accessible to the wrong users etc. That´s all very or at least comparatively easy to determine. But changeability… That´s a whole different thing. Nevertheless over time the customer will develop a feedling if changeability is good enough or degrading. He/she just has to check the development of the frequency of “WTF”s from developers ;-) F and Q are “timeless” requirement categories. Customers want us to deliver on them now. Just focusing on the now, though, is rarely beneficial in the long run. So SoI adds a counterweight to the requirements picture. Customers want SoI - whether they know it or not, whether they state if explicitly or not. In closing A customer´s requirements are not monolithic. They are not all made the same. Rather they fall into different categories. We as developers need to recognize these categories when confronted with some requirement - and take them into account. Only then can we make true professional decisions, i.e. conscious and responsible ones. I call this fundamental trait of software “changeability” and not “flexibility” to distinguish to whom it´s a concern. “Flexibility” to me means, software as is can easily be adapted to a change in its environment, e.g. by tweaking some config data or adding a library which gets picked up by a plug-in engine. “Flexibiltiy” thus is a matter of some user. “Changeability”, on the other hand, to me means, software can easily be changed in its structure to adapt it to new requirements. That´s a matter of the software developer. ?

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• Adding Volcanos and Options - Earthquake Locator, part 2

  - by Bobby Diaz

  Since volcanos are often associated with earthquakes, and vice versa, I decided to show recent volcanic activity on the Earthquake Locator map.  I am pulling the data from a website created for a joint project between the Smithsonian's Global Volcanism Program and the US Geological Survey's Volcano Hazards Program, found here.  They provide a Weekly Volcanic Activity Report as an RSS feed.   I started implementing this new functionality by creating a new Volcano entity in the domain model and adding the following to the EarthquakeService class (I also factored out the common reading/parsing helper methods to a separate FeedReader class that can be used by multiple domain service classes):           private static readonly string VolcanoFeedUrl =             ConfigurationManager.AppSettings["VolcanoFeedUrl"];           /// <summary>         /// Gets the volcano data for the previous week.         /// </summary>         /// <returns>A queryable collection of <see cref="Volcano"/> objects.</returns>         public IQueryable<Volcano> GetVolcanos()         {             var feed = FeedReader.Load(VolcanoFeedUrl);             var list = new List<Volcano>();               if ( feed != null )             {                 foreach ( var item in feed.Items )                 {                     var quake = CreateVolcano(item);                     if ( quake != null )                     {                         list.Add(quake);                     }                 }             }               return list.AsQueryable();         }           /// <summary>         /// Creates a <see cref="Volcano"/> object for each item in the RSS feed.         /// </summary>         /// <param name="item">The RSS item.</param>         /// <returns></returns>         private Volcano CreateVolcano(SyndicationItem item)         {             Volcano volcano = null;             string title = item.Title.Text;             string desc = item.Summary.Text;             double? latitude = null;             double? longitude = null;               FeedReader.GetGeoRssPoint(item, out latitude, out longitude);               if ( !String.IsNullOrEmpty(title) )             {                 title = title.Substring(0, title.IndexOf('-'));             }             if ( !String.IsNullOrEmpty(desc) )             {                 desc = String.Join("\n\n", desc                         .Replace("<p>", "")                         .Split(                             new string[] { "</p>" },                             StringSplitOptions.RemoveEmptyEntries)                         .Select(s => s.Trim())                         .ToArray())                         .Trim();             }               if ( latitude != null && longitude != null )             {                 volcano = new Volcano()                 {                     Id = item.Id,                     Title = title,                     Description = desc,                     Url = item.Links.Select(l => l.Uri.OriginalString).FirstOrDefault(),                     Latitude = latitude.GetValueOrDefault(),                     Longitude = longitude.GetValueOrDefault()                 };             }               return volcano;         } I then added the corresponding LoadVolcanos() method and Volcanos collection to the EarthquakeViewModel class in much the same way I did with the Earthquakes in my previous article in this series. Now that I am starting to add more information to the map, I wanted to give the user some options as to what is displayed and allowing them to choose what gets turned off.  I have updated the MainPage.xaml to look like this:   <UserControl x:Class="EarthquakeLocator.MainPage"     xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"     xmlns:d="http://schemas.microsoft.com/expression/blend/2008"     xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"     xmlns:basic="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls"     xmlns:bing="clr-namespace:Microsoft.Maps.MapControl;assembly=Microsoft.Maps.MapControl"     xmlns:vm="clr-namespace:EarthquakeLocator.ViewModel"     mc:Ignorable="d" d:DesignWidth="640" d:DesignHeight="480" >     <UserControl.Resources>         <DataTemplate x:Key="EarthquakeTemplate">             <Ellipse Fill="Red" Stroke="Black" StrokeThickness="1"                      Width="{Binding Size}" Height="{Binding Size}"                      bing:MapLayer.Position="{Binding Location}"                      bing:MapLayer.PositionOrigin="Center">                 <ToolTipService.ToolTip>                     <StackPanel>                         <TextBlock Text="{Binding Title}" FontSize="14" FontWeight="Bold" />                         <TextBlock Text="{Binding UtcTime}" />                         <TextBlock Text="{Binding LocalTime}" />                         <TextBlock Text="{Binding DepthDesc}" />                     </StackPanel>                 </ToolTipService.ToolTip>             </Ellipse>         </DataTemplate>           <DataTemplate x:Key="VolcanoTemplate">             <Polygon Fill="Gold" Stroke="Black" StrokeThickness="1" Points="0,10 5,0 10,10"                      bing:MapLayer.Position="{Binding Location}"                      bing:MapLayer.PositionOrigin="Center"                      MouseLeftButtonUp="Volcano_MouseLeftButtonUp">                 <ToolTipService.ToolTip>                     <StackPanel>                         <TextBlock Text="{Binding Title}" FontSize="14" FontWeight="Bold" />                         <TextBlock Text="Click icon for more information..." />                     </StackPanel>                 </ToolTipService.ToolTip>             </Polygon>         </DataTemplate>     </UserControl.Resources>       <UserControl.DataContext>         <vm:EarthquakeViewModel AutoLoadData="True" />     </UserControl.DataContext>       <Grid x:Name="LayoutRoot">           <bing:Map x:Name="map" CredentialsProvider="--Your-Bing-Maps-Key--"                   Center="{Binding MapCenter, Mode=TwoWay}"                   ZoomLevel="{Binding ZoomLevel, Mode=TwoWay}">               <bing:MapItemsControl ItemsSource="{Binding Earthquakes}"                                   ItemTemplate="{StaticResource EarthquakeTemplate}" />               <bing:MapItemsControl ItemsSource="{Binding Volcanos}"                                   ItemTemplate="{StaticResource VolcanoTemplate}" />         </bing:Map>           <basic:TabControl x:Name="tabs" VerticalAlignment="Bottom" MaxHeight="25" Opacity="0.7">             <basic:TabItem Margin="90,0,-90,0" MouseLeftButtonUp="TabItem_MouseLeftButtonUp">                 <basic:TabItem.Header>                     <TextBlock x:Name="txtHeader" Text="Options"                                FontSize="13" FontWeight="Bold" />                 </basic:TabItem.Header>                   <StackPanel Orientation="Horizontal">                     <TextBlock Text="Earthquakes:" FontWeight="Bold" Margin="3" />                     <StackPanel Margin="3">                         <CheckBox Content=" &lt; 4.0"                                   IsChecked="{Binding ShowLt4, Mode=TwoWay}" />                         <CheckBox Content="4.0 - 4.9"                                   IsChecked="{Binding Show4s, Mode=TwoWay}" />                         <CheckBox Content="5.0 - 5.9"                                   IsChecked="{Binding Show5s, Mode=TwoWay}" />                     </StackPanel>                       <StackPanel Margin="10,3,3,3">                         <CheckBox Content="6.0 - 6.9"                                   IsChecked="{Binding Show6s, Mode=TwoWay}" />                         <CheckBox Content="7.0 - 7.9"                                   IsChecked="{Binding Show7s, Mode=TwoWay}" />                         <CheckBox Content="8.0 +"                                   IsChecked="{Binding ShowGe8, Mode=TwoWay}" />                     </StackPanel>                       <TextBlock Text="Other:" FontWeight="Bold" Margin="50,3,3,3" />                     <StackPanel Margin="3">                         <CheckBox Content="Volcanos"                                   IsChecked="{Binding ShowVolcanos, Mode=TwoWay}" />                     </StackPanel>                 </StackPanel>               </basic:TabItem>         </basic:TabControl>       </Grid> </UserControl> Notice that I added a VolcanoTemplate that uses a triangle-shaped Polygon to represent the Volcano locations, and I also added a second <bing:MapItemsControl /> tag to the map to bind to the Volcanos collection.  The TabControl found below the map houses the options panel that will present the user with several checkboxes so they can filter the different points based on type and other properties (i.e. Magnitude).  Initially, the TabItem is collapsed to reduce it's footprint, but the screen shot below shows the options panel expanded to reveal the available settings:     I have updated the Source Code and Live Demo to include these new features.   Happy Mapping!

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• Overwriting TFS Web Services

  - by javarg

  In this blog I will share a technique I used to intercept TFS Web Services calls. This technique is a very invasive one and requires you to overwrite default TFS Web Services behavior. I only recommend taking such an approach when other means of TFS extensibility fail to provide the same functionality (this is not a supported TFS extensibility point). For instance, intercepting and aborting a Work Item change operation could be implemented using this approach (consider TFS Subscribers functionality before taking this approach, check Martin’s post about subscribers). So let’s get started. The technique consists in versioning TFS Web Services .asmx service classes. If you look into TFS’s ASMX services you will notice that versioning is supported by creating a class hierarchy between different product versions. For instance, let’s take the Work Item management service .asmx. Check the following .asmx file located at: %Program Files%\Microsoft Team Foundation Server 2010\Application Tier\Web Services\_tfs_resources\WorkItemTracking\v3.0\ClientService.asmx The .asmx references the class Microsoft.TeamFoundation.WorkItemTracking.Server.ClientService3: <%-- Copyright (c) Microsoft Corporation. All rights reserved. --%> <%@ webservice language="C#" Class="Microsoft.TeamFoundation.WorkItemTracking.Server.ClientService3" %> .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 inheritance hierarchy for this service class follows: Note the naming convention used for service versioning (ClientService3, ClientService2, ClientService). We will need to overwrite the latest service version provided by the product (in this case ClientService3 for TFS 2010). The following example intercepts and analyzes WorkItem fields. Suppose we need to validate state changes with more advanced logic other than the provided validations/constraints of the process template. Important: Backup the original .asmx file and create one of your own. Create a Visual Studio Web App Project and include a new ASMX Web Service in the project Add the following references to the project (check the folder %Program Files%\Microsoft Team Foundation Server 2010\Application Tier\Web Services\bin\): Microsoft.TeamFoundation.Framework.Server.dll Microsoft.TeamFoundation.Server.dll Microsoft.TeamFoundation.Server.dll Microsoft.TeamFoundation.WorkItemTracking.Client.QueryLanguage.dll Microsoft.TeamFoundation.WorkItemTracking.Server.DataAccessLayer.dll Microsoft.TeamFoundation.WorkItemTracking.Server.DataServices.dll Replace the default service implementation with the something similar to the following code: Code Snippet /// <summary> /// Inherit from ClientService3 to overwrite default Implementation /// </summary> [WebService(Namespace = "http://schemas.microsoft.com/TeamFoundation/2005/06/WorkItemTracking/ClientServices/03", Description = "Custom Team Foundation WorkItemTracking ClientService Web Service")] public class CustomTfsClientService : ClientService3 {     [WebMethod, SoapHeader("requestHeader", Direction = SoapHeaderDirection.In)]     public override bool BulkUpdate(         XmlElement package,         out XmlElement result,         MetadataTableHaveEntry[] metadataHave,         out string dbStamp,         out Payload metadata)     {         var xe = XElement.Parse(package.OuterXml);         // We only intercept WorkItems Updates (we can easily extend this sample to capture any operation).         var wit = xe.Element("UpdateWorkItem");         if (wit != null)         {             if (wit.Attribute("WorkItemID") != null)             {                 int witId = (int)wit.Attribute("WorkItemID");                 // With this Id. I can query TFS for more detailed information, using TFS Client API (assuming the WIT already exists).                 var stateChanged =                     wit.Element("Columns").Elements("Column").FirstOrDefault(c => (string)c.Attribute("Column") == "System.State");                 if (stateChanged != null)                 {                     var newStateName = stateChanged.Element("Value").Value;                     if (newStateName == "Resolved")                     {                         throw new Exception("Cannot change state to Resolved!");                     }                 }             }         }         // Finally, we call base method implementation         return base.BulkUpdate(package, out result, metadataHave, out dbStamp, out metadata);     } } .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; } 4. Build your solution and overwrite the original .asmx with the new implementation referencing our new service version (don’t forget to backup it up first). 5. Copy your project’s .dll into the following path: %Program Files%\Microsoft Team Foundation Server 2010\Application Tier\Web Services\bin 6. Try saving a WorkItem into the Resolved state. Enjoy!

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• Adaptive ADF/WebCenter template for the iPad

  - by Maiko Rocha

  One of my WebCenter Portal customers was asking about adaptive design with ADF/WebCenter Portal and how they could go about creating an adaptive iPad template for their WebCenter Portal application. They were looking not only for the out-of-the-box support for mobile Safari which is certified against PS5+ (11.1.1.6) for ADF/WebCenter - but also to create a specific template to streamline their workflow on the iPad. Seems like they wanted something in the lines of Yahoo! Mail provides for the iPad - so the example I will use is shamelessly inspired by Y! Mail's iPad UI.  But first, let's quickly understand how can we bake in some adaptive goodness into ADF Faces. First thing we need to understand is, yes, there are a couple of constraints that we will need to work around, namely, the use or layout managers and skins. Please also keep in mind that I'm not and I don't pretend to be a web designer, much less an UX specialist, so feel free to leave your thoughts on the matter in the comments section. Now, back to the limitations. Layout Managers ADF Faces layout managers create an abstraction on top of the generated HTML code for a page so a developer doesn't need to be worried about how to size and dimension the UI layout (eg, af:panelStretchLayout). Although layout managers are very helpful, in this specific situation we will need to know a little bit more of how the final HTML is being rendered so we can apply the CSS class accordingly and create transition containers where the media queries will be applied - now, if you're using 11gR2 (11.1.2.2.3) there's the new component af:panelGridLayout (here and here) that will greatly improve creating responsive templates and pages because it is based on the grid/fluid systems and will generate straight out to DIVs on your final page. For now, I'm limited to PS5 and the af:panelStretchLayout component as a starting point because that's the release my customer is on. Skins You won't be able to use media queries, or use anything with "@" notation on the skin CSS file - the skin pre-processor will remove all extraneous "@" from the CSS file. The solution is to split your CSS in two separate files: a skin CSS file and plain CSS where you will add the media queries. The issue here is that you won't be able to use media queries for any faces components. We can, though, still apply the media queries for the components like af:panelGroupLayout and af:panelBorderLayout through their styleClass property to enable these components to be responsive to to the iPad orientation, by changing its dimensions, font sizes, hide/show areas, etc. Difference between responsive and adaptive design The best definition of adaptive vs responsive web design I could find is this: “Responsive web design,” as coined by Ethan Marcotte, means “fluid grids, fluid images/media & media queries.” “Adaptive web design,” as I use it, is about creating interfaces that adapt to the user’s capabilities (in terms of both form and function). To me, “adaptive web design” is just another term for “progressive enhancement” of which responsive web design can (an often should) be an integral part, but is a more holistic approach to web design in that it also takes into account varying levels of markup, CSS, JavaScript and assistive technology support. Responsive/adapative web design is much more than slapping an HTML template with CSS around your content or application. The content and application themselves are part of your web design - in other words, a responsive template is just an afterthought if it is not originating from a responsive design the involves the whole web application/s. Tips on responsive / adapative design with ADF/WebCenter Some of the tips listed below were already mentioned in multiple blog posts about ADF layout and skinning, but it is still worth remembering: a simple guideline for ADF/WebCenter apps would be to first create a high-level group of devices, for example: smartphones, tablets,  and desktop. For each of these large groups, create the basic structure to provide responsiveness: a page template, a skin, and an external CSS: pagetemplate_smartphone.jspx, smartphone_skin.css, smartphone-responsive.css pagetemplate_tablet.jspx, tablet_skin.css, tablet-responsive.css pagetemplate_desktop.jspx, desktop_skin.css, desktop-responsive.css These three assets can be changed on the fly through an user-agent check on the server side, delivering the right UI to the right device. Within each of the assets, you can make fine adjustments for each subgroup of devices with media queries - for example, smart phones with different screen dimensions and pixel density. Having these three groups and the corresponding assets per group seem to be a good compromise between trying to put everything on a single set of assets - specially considering the constraints above - and going to the other side of the spectrum to create assets per discrete device (iPhone4, iPhone5, Nexus, S3, etc.). Keep in mind that these are my rules and are not in any shape or form a best practice - this is how it fits best for the scenarios I've been working with. If you need to use HTML tags on your page, surround them with af:group to protect the DOM structure For stretchable/fluid layouts: Use non-stretching containers: panelGroupLayout, panelBorderLayout, … panelBorderLayout can be used to approximate HTML table component To avoid multiple scroll bars, do not nest scrolling PanelGroupLayout components. Consider layout="vertical" For stretchable/fluid layouts: Most stretchable ADF components also work in flowing context with dimensionsFrom="auto" To stretch a component horizontally, use styleClass="AFStretchWidth" instead of  "width:100%" Skinning Don't use CSS3 @media, @import, animations, etc. on skin css files. They will be removed. CSS3 properties within a class (box-shadow, transition, etc.) work just fine. Consider resetting some skin classes to better control their rendering: body {color: inherit;font: inherit;} af|document {-tr-inhibit: all;} af|commandLink {-tr-inhibit: all;} af|goLink {-tr-inhibit: all;} af|inputText::content {font: inherit;} Specific meta tags and CSS properties: Use  <meta name="viewport" content="width=device-width, initial-scale=1.0, minimum-scale=1.0, maximum-scale=1.0"/> to avoid zooming (if you want) Use -webkit-overflow-scrolling: touch to enable native momentum scrolling within overflown areas (here) Use text-rendering: optmizeLegibility to improve readability. (here) User text-overflow: ellipsis to gracefully crop overflown text. (here) The meta-tags are included in each and every page in the metaContainer facet of af:document tag. You can also use a javascript to inject the meta-tags from the template. For the purpose of the example, I wanted to use as few workarounds as possible.   The iPad template and sample application This sample application has been built as a WebCenter Portal application, but you will also be able to reuse the template and techniques on your vanilla ADF application. Keep in mind that I'm neither a designer nor a CSS specialist, so please don't bash me too much on the messy CSS file you'll find on the application.  I've extended the provided PreferencesBean class that comes with WebCenter Portal and added code to dinamically change the template and skin on the fly.   This is the sample application in landscape orientation: This is the sample application in portrait orientation - the left side menu hides automatically based on a CSS media query: Another screenshot with a skinned popup opened: This is a sample application for you to play with - ideally you shouldn't use it as a starting point. On the left side bar you will find links rendered from a WebCenter Portal navigation model - the link triggers a full request through an af:goLink, while the light blue PPR button triggers a PPR navigation. The dark blue toolbar buttons at the top don't have any function,while the Approve and Reject buttons show a skinned popup. The search box of course doesn't have any behavior attahed to it either. There's a known issue right now with some PPR calls that are randomly generating a 403 error redirecting to the login page - I didn't have time to investigate if this is iOS6 specific or not - if you have any insights please let me know your findings. You can download the sample here.

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• CodePlex Daily Summary for Thursday, March 11, 2010

  CodePlex Daily Summary for Thursday, March 11, 2010New ProjectsASP.NET Wiki Control: This ASP.NET user control allows you to embed a very useful wiki directly into your already existing ASP.NET website taking advantage of the popula...BabyLog: Log baby daily activity.buddyHome: buddyHome is a project that can make your home smarter. as good as your buddy. Cloud Community: Cloud Community makes it easier for organizations to have a simple to use community platform. Our mission is to create an easy to use community pl...Community Connectors for Microsoft CRM 4.0: Community Connectors for Microsoft CRM 4.0 allows Microsoft CRM 4.0 customers and partners to monitor and analyze customers’ interaction from their...Console Highlighter: Hightlights Microsoft Windows Command prompt (cmd.exe) by outputting ANSI VT100 Control sequences to color the output. These sequences are not hand...Cornell Store: This is IN NO WAY officially affiliated or related to the Cornell University store. Instead, this is a project that I am doing for a class. Ther...DevUtilities: This project is for creating some utility tools, and they will be useful during the development.DotNetNuke® Skin Maple: A DotNetNuke Design Challenge skin package submitted to the "Personal" category by DyNNamite.co.uk. The package includes 4 color variations and sev...HRNet: HRNetIIS Web Site Monitoring: A software for monitor a particular web site on IIS, even if its IP is sharing between different web site.Iowa Code Camp: The source code for the Iowa Code Camp website.Leonidas: Leonidas is a virtual tutorLunch 'n Learn: The Lunch 'n Learn web application is an open source ASP.NET MVC application that allows you to setup lunch 'n learn presentations for your team, c...MNT Cryptography: A very simple cryptography classMooiNooi MVC2LINQ2SQL Web Databinder: mvc2linq2sql is a databinder for ASP.NET MVC that make able developer to clean bind object from HTML FORMS to Linq entities. Even 1 to N relations ...MoqBot: MoqBot is an auto mocking library for Moq and Ninject.mtExperience1: hoiMvcPager: MvcPager is a free paging component for ASP.NET MVC web application, it exposes a series of extension methods for using in ASP.NET MVC applications...OCal: OCal is based on object calisthenics to identify code smellsPex Custom Arithmetic Solver: Pex Custom Arithmetic Solver contains a collection of meta-heuristic search algorithms. The goal is to improve Pex's code coverage for code involvi...SetControls: Расширеные контролы для ASP.NET приложений. Полная информация ближе к релизу...shadowrage1597: CTC 195 Game Design classSharePoint Team-Mailer: A SharePoint 2007 solution that defines a generic CustomList for sending e-mails to SharePoint Groups.Sql Share: SQL Share is a collaboration tool used within the science to allow database engineers to work tightly with domain scientists.TechCalendar: Tech Events Calendar ASP.NET project.ZLYScript: A very simple script language compiler.New ReleasesALGLIB: ALGLIB 2.4.0: New ALGLIB release contains: improved versions of several linear algebra algorithms: QR decomposition, matrix inversion, condition number estimatio...AmiBroker Plug-Ins with C#: AmiBroker Plug-Ins v0.0.2: Source codes and a binaryAppFabric Caching UI Admin Tool: AppFabric Caching Beta 2 UI Admin Tool: System Requirements:.NET 4.0 RC AppFabric Caching Beta2 Test On:Win 7 (64x)Autodocs - WCF REST Automatic API Documentation Generator: Autodocs.ServiceModel.Web: This archive contains the reference DLL, instructions and license.Compact Plugs & Compact Injection: Compact Injection and Compact Plugs 1.1 Beta: First release of Compact Plugs (CP). The solution includes a simple example project of CP, called "TestCompactPlugs1". Also some fixes where made ...Console Highlighter: Console Highlighter 0.9 (preview release): Preliminary release.Encrypted Notes: Encrypted Notes 1.3: This is the latest version of Encrypted Notes (1.3). It has an installer - it will create a directory 'CPascoe' in My Documents. The last one was ...Family Tree Analyzer: Version 1.0.2: Family Tree Analyzer Version 1.0.2 This early beta version implements loading a gedcom file and displaying some basic reports. These reports inclu...FRC1103 - FRC Dashboard viewer: 2010 Documentation v0.1: This is my current version of the control system documentation for 2010. It isn't complete, but it has the information required for a custom dashbo...jQuery.cssLess: jQuery.cssLess 0.5 (Even less release): NEW - support for nested special CSS classes (like :hover) MAIN RELEASE This release, code "Even less", is the one that will interpret cssLess wit...MooiNooi MVC2LINQ2SQL Web Databinder: MooiNooi MVC2LINQ2SQL DataBinder: I didn't try this... I just took it off from my project. Please, tell me any problem implementing in your own development and I'll be pleased to h...MvcPager: MvcPager 1.2 for ASP.NET MVC 1.0: MvcPager 1.2 for ASP.NET MVC 1.0Mytrip.Mvc: Mytrip 1.0 preview 1: Article Manager Blog Manager L2S Membership(.NET Framework 3.5) EF Membership(.NET Framework 4) User Manager File Manager Localization Captcha ...NodeXL: Network Overview, Discovery and Exploration for Excel: NodeXL Excel 2007 Template, version 1.0.1.117: The NodeXL Excel 2007 template displays a network graph using edge and vertex lists stored in an Excel 2007 workbook. What's NewThis version adds ...Pex Custom Arithmetic Solver: PexCustomArithmeticSolver: This is the alpha release containing the Alternating Variable Method and Evolution Strategies to try and solve constraints over floating point vari...Scrum Sprint Monitor: v1.0.0.44877: What is new in this release? Major performance increase in animations (up to 50 fps from 2 fps) by replacing DropShadow effect with png bitmaps; ...sELedit: sELedit v1.0b: + Added support for empty strings / wstrings + Fixed: critical bug in configuration files (list 53)sPWadmin: pwAdmin v0.9_nightly: + Fixed: XML editor can now open and save character templates + Added: PWI item name database + Added: Plugin SupportTechCalendar: Events Calendar v.1.0: Initial release.The Silverlight Hyper Video Player [http://slhvp.com]: Beta 2: Beta 2.0 Some fixes from Beta 1, and a couple small enhancements. Intensive testing continues, and I will continue to update the code at least ever...ThreadSafe.Caching: 2010.03.10.1: Updates to the scavanging behaviour since last release. Scavenging will now occur every 30 seconds by default and all objects in the cache will be ...VCC: Latest build, v2.1.30310.0: Automatic drop of latest buildVisual Studio DSite: Email Sender (C++): The same Email Sender program that I but made in visual c plus plus 2008 instead of visual basic 2008.Web Forms MVP: Web Forms MVP CTP7: The release can be considered stable, and is in use behind several high traffic, public websites. It has been marked as a CTP release as it is not ...White Tiger: 0.0.3.1: Now you can load or create files with whatever root element you want *check f or sets file permisionsMost Popular ProjectsMetaSharpWBFS ManagerRawrAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesASP.NET Ajax LibraryMost Active ProjectsUmbraco CMSRawrSDS: Scientific DataSet library and toolsN2 CMSFasterflect - A Fast and Simple Reflection APIjQuery Library for SharePoint Web ServicesBlogEngine.NETFarseer Physics Enginepatterns & practices – Enterprise LibraryCaliburn: An Application Framework for WPF and Silverlight

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• SQL SERVER – Interview Questions and Answers – Frequently Asked Questions – Introduction – Day 1 of 31

  - by pinaldave

  List of all the Interview Questions and Answers Series blogs Posts covering interview questions and answers always make for interesting reading.  Some people like the subject for their helpful hints and thought provoking subject, and others dislike these posts because they feel it is nothing more than cheating.  I’d like to discuss the pros and cons of a Question and Answer format here. Interview Questions and Answers are Helpful Just like blog posts, books, and articles, interview Question and Answer discussions are learning material.  The popular Dummy’s books or Idiots Guides are not only for “dummies,” but can help everyone relearn the fundamentals.  Question and Answer discussions can serve the same purpose.  You could call this SQL Server Fundamentals or SQL Server 101. I have administrated hundreds of interviews during my career and I have noticed that sometimes an interviewee with several years of experience lacks an understanding of the fundamentals.  These individuals have been in the industry for so long, usually working on a very specific project, that the ABCs of the business have slipped their mind. Or, when a college graduate is looking to get into the industry, he is not expected to have experience since he is just graduated. However, the new grad is expected to have an understanding of fundamentals and theory.  Sometimes after the stress of final exams and graduation, it can be difficult to remember the correct answers to interview questions, though. An interview Question and Answer discussion can be very helpful to both these individuals.  It is simply a way to go back over the building blocks of a topic.  Many times a simple review like this will help “jog” your memory, and all those previously-memorized facts will come flooding back to you.  It is not a way to re-learn a topic, but a way to remind yourself of what you already know. A Question and Answer discussion can also be a way to go over old topics in a more interesting manner.  Especially if you have been working in the industry, or taking lots of classes on the topic, everything you read can sound like a repeat of what you already know.  Going over a topic in a new format can make the material seem fresh and interesting.  And an interested mind will be more engaged and remember more in the end. Interview Questions and Answers are Harmful A common argument against a Question and Answer discussion is that it will give someone a “cheat sheet.” A new guy with relatively little experience can read the interview questions and answers, and then memorize them. When an interviewer asks him the same questions, he will repeat the answers and get the job. Honestly, is he good hire because he memorized the interview questions? Wouldn’t it be better for the interviewer to hire someone with actual experience?  The answer is not as easy as it seems – there are many different factors to be considered. If the interviewer is asking fundamentals-related questions only, he gets the answers he wants to hear, and then hires this first candidate – there is a good chance that he is hiring based on personality rather than experience.  If the interviewer is smart he will ask deeper questions, have more than one person on the interview team, and interview a variety of candidates.  If one interviewee happens to memorize some answers, it usually doesn’t mean he will automatically get the job at the expense of more qualified candidates. Another argument against interview Question and Answers is that it will give candidates a false sense of confidence, and that they will appear more qualified than they are. Well, if that is true, it will not last after the first interview when the candidate is asked difficult questions and he cannot find the answers in the list of interview Questions and Answers.  Besides, confidence is one of the best things to walk into an interview with! In today’s competitive job market, there are often hundreds of candidates applying for the same position.  With so many applicants to choose from, interviewers must make decisions about who to call back and who to hire based on their gut feeling.  One drawback to reading an interview Question and Answer article is that you might sound very boring in your interview – saying the same thing as every single candidate, and parroting answers that sound like someone else wrote them for you – because they did.  However, it is definitely better to go to an interview prepared, just make sure that you give a lot of thought to your answers to make them sound like your own voice.  Remember that you will be hired based on your skills as well as your personality, so don’t think that having all the right answers will make get you hired.  A good interviewee will be prepared, confident, and know how to stand out. My Opinion A list of interview Questions and Answers is really helpful as a refresher or for beginners. To really ace an interview, one needs to have real-world, hands-on experience with SQL Server as well. Interview questions just serve as a starter or easy read for experienced professionals. When I have to learn new technology, I often search online for interview questions and get an idea about the breadth and depth of the technology. Next Action I am going to write about interview Questions and Answers for next 30 days. I have previously written a series of interview questions and answers; now I have re-written them keeping the latest version of SQL Server and current industry progress in mind. If you have faced interesting interview questions or situations, please write to me and I will publish them as a guest post. If you want me to add few more details, leave a comment and I will make sure that I do my best to accommodate. Tomorrow we will start the interview Questions and Answers series, with a few interesting stories, best practices and guest posts. We will have a prize give-away and other awards when the series ends. List of all the Interview Questions and Answers Series blogs Reference: Pinal Dave (http://blog.SQLAuthority.com) Filed under: Pinal Dave, PostADay, SQL, SQL Authority, SQL Interview Questions and Answers, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• Launching a WPF Window in a Separate Thread, Part 1

  - by Reed

  Typically, I strongly recommend keeping the user interface within an application’s main thread, and using multiple threads to move the actual “work” into background threads.  However, there are rare times when creating a separate, dedicated thread for a Window can be beneficial.  This is even acknowledged in the MSDN samples, such as the Multiple Windows, Multiple Threads sample.  However, doing this correctly is difficult.  Even the referenced MSDN sample has major flaws, and will fail horribly in certain scenarios.  To ease this, I wrote a small class that alleviates some of the difficulties involved. The MSDN Multiple Windows, Multiple Threads Sample shows how to launch a new thread with a WPF Window, and will work in most cases.  The sample code (commented and slightly modified) works out to the following: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create and show the Window Window1 tempWindow = new Window1(); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Set the apartment state newWindowThread.SetApartmentState(ApartmentState.STA); // Make the thread a background thread newWindowThread.IsBackground = true; // Start the thread newWindowThread.Start(); .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; } This sample creates a thread, marks it as single threaded apartment state, and starts the Dispatcher on that thread. That is the minimum requirements to get a Window displaying and handling messages correctly, but, unfortunately, has some serious flaws. The first issue – the created thread will run continuously until the application shuts down, given the code in the sample.  The problem is that the ThreadStart delegate used ends with running the Dispatcher.  However, nothing ever stops the Dispatcher processing.  The thread was created as a Background thread, which prevents it from keeping the application alive, but the Dispatcher will continue to pump dispatcher frames until the application shuts down. In order to fix this, we need to call Dispatcher.InvokeShutdown after the Window is closed.  This would require modifying the above sample to subscribe to the Window’s Closed event, and, at that point, shutdown the Dispatcher: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This eliminates the first issue.  Now, when the Window is closed, the new thread’s Dispatcher will shut itself down, which in turn will cause the thread to complete. The above code will work correctly for most situations.  However, there is still a potential problem which could arise depending on the content of the Window1 class.  This is particularly nasty, as the code could easily work for most windows, but fail on others. The problem is, at the point where the Window is constructed, there is no active SynchronizationContext.  This is unlikely to be a problem in most cases, but is an absolute requirement if there is code within the constructor of Window1 which relies on a context being in place. While this sounds like an edge case, it’s fairly common.  For example, if a BackgroundWorker is started within the constructor, or a TaskScheduler is built using TaskScheduler.FromCurrentSynchronizationContext() with the expectation of synchronizing work to the UI thread, an exception will be raised at some point.  Both of these classes rely on the existence of a proper context being installed to SynchronizationContext.Current, which happens automatically, but not until Dispatcher.Run is called.  In the above case, SynchronizationContext.Current will return null during the Window’s construction, which can cause exceptions to occur or unexpected behavior. Luckily, this is fairly easy to correct.  We need to do three things, in order, prior to creating our Window: Create and initialize the Dispatcher for the new thread manually Create a synchronization context for the thread which uses the Dispatcher Install the synchronization context Creating the Dispatcher is quite simple – The Dispatcher.CurrentDispatcher property gets the current thread’s Dispatcher and “creates a new Dispatcher if one is not already associated with the thread.”  Once we have the correct Dispatcher, we can create a SynchronizationContext which uses the dispatcher by creating a DispatcherSynchronizationContext.  Finally, this synchronization context can be installed as the current thread’s context via SynchronizationContext.SetSynchronizationContext.  These three steps can easily be added to the above via a single line of code: // Create a thread Thread newWindowThread = new Thread(new ThreadStart( () => { // Create our context, and install it: SynchronizationContext.SetSynchronizationContext( new DispatcherSynchronizationContext( Dispatcher.CurrentDispatcher)); Window1 tempWindow = new Window1(); // When the window closes, shut down the dispatcher tempWindow.Closed += (s,e) => Dispatcher.CurrentDispatcher.BeginInvokeShutdown(DispatcherPriority.Background); tempWindow.Show(); // Start the Dispatcher Processing System.Windows.Threading.Dispatcher.Run(); })); // Setup and start thread as before This now forces the synchronization context to be in place before the Window is created and correctly shuts down the Dispatcher when the window closes. However, there are quite a few steps.  In my next post, I’ll show how to make this operation more reusable by creating a class with a far simpler API…

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• Run Your Tests With Any NUnit Version

  - by Alois Kraus

  I always thought that the NUnit test runners and the test assemblies need to reference the same NUnit.Framework version. I wanted to be able to run my test assemblies with the newest GUI runner (currently 2.5.3). Ok so all I need to do is to reference both NUnit versions the newest one and the official for the current project. There is a nice article form Kent Bogart online how to reference the same assembly multiple times with different versions. The magic works by referencing one NUnit assembly with an alias which does prefix all types inside it. Then I could decorate my tests with the TestFixture and Test attribute from both NUnit versions and everything worked fine except that this was ugly. After playing a little bit around to make it simpler I found that I did not need to reference both NUnit.Framework assemblies. The test runners do not require the TestFixture and Test attribute in their specific version. That is really neat since the test runners are instructed by attributes what to do in a declarative way there is really no need to tie the runners to a specific version. At its core NUnit has this little method hidden to find matching TestFixtures and Tests   public bool CanBuildFrom(Type type) {     if (!(!type.IsAbstract || type.IsSealed))     {         return false;     }     return (((Reflect.HasAttribute(type,           "NUnit.Framework.TestFixtureAttribute", true) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestAttribute"       , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TestCaseAttribute"   , true)) ||               Reflect.HasMethodWithAttribute(type, "NUnit.Framework.TheoryAttribute"     , true)); } That is versioning and backwards compatibility at its best. I tell NUnit what to do by decorating my tests classes with NUnit Attributes and the runner executes my intent without the need to bind me to a specific version. The contract between NUnit versions is actually a bit more complex (think of AssertExceptions) but this is also handled nicely by using not the concrete type but simply to check for the catched exception type by string. What can we learn from this? Versioning can be easy if the contract is small and the users of your library use it in a declarative way (Attributes). Everything beyond it will force you to reference several versions of the same assembly with all its consequences. Type equality is lost between versions so none of your casts will work. That means that you cannot simply use IBigInterface in two versions. You will need a wrapper to call the correct versioned one. To get out of this mess you can use one (and only one) version agnostic driver to encapsulate your business logic from the concrete versions. This is of course more work but as NUnit shows it can be easy. Simplicity is therefore not a nice thing to have but also requirement number one if you intend to make things more complex in version two and want to support any version (older and newer). Any interaction model above easy will not be maintainable. There are different approached to versioning. Below are my own personal observations how versioning works within the  .NET Framwork and NUnit.   Versioning Models 1. Bug Fixing and New Isolated Features When you only need to fix bugs there is no need to break anything. This is especially true when you have a big API surface. Microsoft did this with the .NET Framework 3.0 which did leave the CLR as is but delivered new assemblies for the features WPF, WCF and Windows Workflow Foundations. Their basic model was that the .NET 2.0 assemblies were declared as red assemblies which must not change (well mostly but each change was carefully reviewed to minimize the risk of breaking changes as much as possible) whereas the new green assemblies of .NET 3,3.5 did not have such obligations since they did implement new unrelated features which did not have any impact on the red assemblies. This is versioning strategy aimed at maximum compatibility and the delivery of new unrelated features. If you have a big API surface you should strive hard to do the same or you will break your customers code with every release. 2. New Breaking Features There are times when really new things need to be added to an existing product. The .NET Framework 4.0 did change the CLR in many ways which caused subtle different behavior although the API´s remained largely unchanged. Sometimes it is possible to simply recompile an application to make it work (e.g. changed method signature void Func() –> bool Func()) but behavioral changes need much more thought and cannot be automated. To minimize the impact .NET 2.0,3.0,3.5 applications will not automatically use the .NET 4.0 runtime when installed but they will keep using the “old” one. What is interesting is that a side by side execution model of both CLR versions (2 and 4) within one process is possible. Key to success was total isolation. You will have 2 GCs, 2 JIT compilers, 2 finalizer threads within one process. The two .NET runtimes cannot talk  (except via the usual IPC mechanisms) to each other. Both runtimes share nothing and run independently within the same process. This enables Explorer plugins written for the CLR 2.0 to work even when a CLR 4 plugin is already running inside the Explorer process. The price for isolation is an increased memory footprint because everything is loaded and running two times.   3. New Non Breaking Features It really depends where you break things. NUnit has evolved and many different Assert, Expect… methods have been added. These changes are all localized in the NUnit.Framework assembly which can be easily extended. As long as the test execution contract (TestFixture, Test, AssertException) remains stable it is possible to write test executors which can run tests written for NUnit 10 because the execution contract has not changed. It is possible to write software which executes other components in a version independent way but this is only feasible if the interaction model is relatively simple.   Versioning software is hard and it looks like it will remain hard since you suddenly work in a severely constrained environment when you try to innovate and to keep everything backwards compatible at the same time. These are contradicting goals and do not play well together. The easiest way out of this is to carefully watch what your customers are doing with your software. Minimizing the impact is much easier when you do not need to guess how many people will be broken when this or that is removed.

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• Listing common SQL Code Smells.

  - by Phil Factor

  Once you’ve done a number of SQL Code-reviews, you’ll know those signs in the code that all might not be well. These ’Code Smells’ are coding styles that don’t directly cause a bug, but are indicators that all is not well with the code. . Kent Beck and Massimo Arnoldi seem to have coined the phrase in the "OnceAndOnlyOnce" page of www.C2.com, where Kent also said that code "wants to be simple". Bad Smells in Code was an essay by Kent Beck and Martin Fowler, published as Chapter 3 of the book ‘Refactoring: Improving the Design of Existing Code’ (ISBN 978-0201485677) Although there are generic code-smells, SQL has its own particular coding habits that will alert the programmer to the need to re-factor what has been written. See Exploring Smelly Code   and Code Deodorants for Code Smells by Nick Harrison for a grounding in Code Smells in C# I’ve always been tempted by the idea of automating a preliminary code-review for SQL. It would be so useful to trawl through code and pick up the various problems, much like the classic ‘Lint’ did for C, and how the Code Metrics plug-in for .NET Reflector by Jonathan 'Peli' de Halleux is used for finding Code Smells in .NET code. The problem is that few of the standard procedural code smells are relevant to SQL, and we need an agreed list of code smells. Merrilll Aldrich made a grand start last year in his blog Top 10 T-SQL Code Smells.However, I'd like to make a start by discovering if there is a general opinion amongst Database developers what the most important SQL Smells are. One can be a bit defensive about code smells. I will cheerfully write very long stored procedures, even though they are frowned on. I’ll use dynamic SQL occasionally. You can only use them as an aid for your own judgment and it is fine to ‘sign them off’ as being appropriate in particular circumstances. Also, whole classes of ‘code smells’ may be irrelevant for a particular database. The use of proprietary SQL, for example, is only a ‘code smell’ if there is a chance that the database will have to be ported to another RDBMS. The use of dynamic SQL is a risk only with certain security models. As the saying goes,  a CodeSmell is a hint of possible bad practice to a pragmatist, but a sure sign of bad practice to a purist. Plamen Ratchev’s wonderful article Ten Common SQL Programming Mistakes lists some of these ‘code smells’ along with out-and-out mistakes, but there are more. The use of nested transactions, for example, isn’t entirely incorrect, even though the database engine ignores all but the outermost: but it does flag up the possibility that the programmer thinks that nested transactions are supported. If anything requires some sort of general agreement, the definition of code smells is one. I’m therefore going to make this Blog ‘dynamic, in that, if anyone twitters a suggestion with a #SQLCodeSmells tag (or sends me a twitter) I’ll update the list here. If you add a comment to the blog with a suggestion of what should be added or removed, I’ll do my best to oblige. In other words, I’ll try to keep this blog up to date. The name against each 'smell' is the name of the person who Twittered me, commented about or who has written about the 'smell'. it does not imply that they were the first ever to think of the smell! Use of deprecated syntax such as *= (Dave Howard) Denormalisation that requires the shredding of the contents of columns. (Merrill Aldrich) Contrived interfaces Use of deprecated datatypes such as TEXT/NTEXT (Dave Howard) Datatype mis-matches in predicates that rely on implicit conversion.(Plamen Ratchev) Using Correlated subqueries instead of a join   (Dave_Levy/ Plamen Ratchev) The use of Hints in queries, especially NOLOCK (Dave Howard /Mike Reigler) Few or No comments. Use of functions in a WHERE clause. (Anil Das) Overuse of scalar UDFs (Dave Howard, Plamen Ratchev) Excessive ‘overloading’ of routines. The use of Exec xp_cmdShell (Merrill Aldrich) Excessive use of brackets. (Dave Levy) Lack of the use of a semicolon to terminate statements Use of non-SARGable functions on indexed columns in predicates (Plamen Ratchev) Duplicated code, or strikingly similar code. Misuse of SELECT * (Plamen Ratchev) Overuse of Cursors (Everyone. Special mention to Dave Levy & Adrian Hills) Overuse of CLR routines when not necessary (Sam Stange) Same column name in different tables with different datatypes. (Ian Stirk) Use of ‘broken’ functions such as ‘ISNUMERIC’ without additional checks. Excessive use of the WHILE loop (Merrill Aldrich) INSERT ... EXEC (Merrill Aldrich) The use of stored procedures where a view is sufficient (Merrill Aldrich) Not using two-part object names (Merrill Aldrich) Using INSERT INTO without specifying the columns and their order (Merrill Aldrich) Full outer joins even when they are not needed. (Plamen Ratchev) Huge stored procedures (hundreds/thousands of lines). Stored procedures that can produce different columns, or order of columns in their results, depending on the inputs. Code that is never used. Complex and nested conditionals WHILE (not done) loops without an error exit. Variable name same as the Datatype Vague identifiers. Storing complex data  or list in a character map, bitmap or XML field User procedures with sp_ prefix (Aaron Bertrand)Views that reference views that reference views that reference views (Aaron Bertrand) Inappropriate use of sql_variant (Neil Hambly) Errors with identity scope using SCOPE_IDENTITY @@IDENTITY or IDENT_CURRENT (Neil Hambly, Aaron Bertrand) Schemas that involve multiple dated copies of the same table instead of partitions (Matt Whitfield-Atlantis UK) Scalar UDFs that do data lookups (poor man's join) (Matt Whitfield-Atlantis UK) Code that allows SQL Injection (Mladen Prajdic) Tables without clustered indexes (Matt Whitfield-Atlantis UK) Use of "SELECT DISTINCT" to mask a join problem (Nick Harrison) Multiple stored procedures with nearly identical implementation. (Nick Harrison) Excessive column aliasing may point to a problem or it could be a mapping implementation. (Nick Harrison) Joining "too many" tables in a query. (Nick Harrison) Stored procedure returning more than one record set. (Nick Harrison) A NOT LIKE condition (Nick Harrison) excessive "OR" conditions. (Nick Harrison) User procedures with sp_ prefix (Aaron Bertrand) Views that reference views that reference views that reference views (Aaron Bertrand) sp_OACreate or anything related to it (Bill Fellows) Prefixing names with tbl_, vw_, fn_, and usp_ ('tibbling') (Jeremiah Peschka) Aliases that go a,b,c,d,e... (Dave Levy/Diane McNurlan) Overweight Queries (e.g. 4 inner joins, 8 left joins, 4 derived tables, 10 subqueries, 8 clustered GUIDs, 2 UDFs, 6 case statements = 1 query) (Robert L Davis) Order by 3,2 (Dave Levy) MultiStatement Table functions which are then filtered 'Sel * from Udf() where Udf.Col = Something' (Dave Ballantyne) running a SQL 2008 system in SQL 2000 compatibility mode(John Stafford)

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• CodePlex Daily Summary for Saturday, May 15, 2010

  CodePlex Daily Summary for Saturday, May 15, 2010New ProjectsBizTalk EDI Guidance: BizTalk EDI Guidance is intended to simplify the delivery of EDI solutions by leveraging the ESB Toolkit. This project is currently Alpha and sh...Continues Integration Sample: I'm providing a series of blog post to show a complete CI process using CruiseControl.Net and msbuild. The source code for this series is hosted here.DioM2D: My Dragons in our Midst RPG. Runs on my custom Starlight Engine.Ethical Hacking ASP.NET: Security tools and guidelines for white-hat hacking and protecting ASP.NET web applications.Farseer Engine with XNATouch: Farseer is great engine for game physics. This implementation uses XNATouch framework.Feature Builder Guidance Extensions: Feature Builder Guidance Extensions are Feature Extensions which extend the guidance for the Feature Building experience. Each FBGX will be suppli...Microsoft Office Document Security: MODS is a plugin for office 2007 thats includes Hash Encryption, Hex Convertion and more. Plugins: MODS For Word still working on (MODS for Excel ...Minimize Engine (XNA): The Minimize Engine is a basic 3D Games Engine created using XNA, with its primary focus around Grid Based games.MSForge TownCrier: This project is meant to build a notification and calling system for MSForge.net User Groups.NatureProtector: Silverlight 4 project.OutSync: OutSync is a free Windows desktop application that syncs photos of your Facebook friends with matching contacts in Microsoft Outlook. It allows you...Quick Save Images, Clipboard save to file, Quick save, bmp, png, jpeg, Image: ClipSa is a very small tool for very quick picture saving. You put some picture into the clipboard (PrintScrn/Alt-PrintScrn/Ctrl-C), ClipSa saves ...ResHelper Manager: Resource strings management tool that creates localization files for any type of localization target (asp.net, wpf and so on...)SecureCookieHttpModule: Secure your session cookie (and other session-based) cookies for replay attacks using this easy to use ASP.NET HttpModule.simpleChMS: A Church Management System (ChMS) designed for churches or ministries like youth groups that want to facilitate better care or theie membership. Fo...sMAPtool: -SPDomainObject: mapping strong type objects to sp listsSQL Trim: This project aims at developing a universal trim function for Microsoft SQL Server. It trims: 1) pre spaces 2) post spaces 3) double spaces 3) subs...TurretGunner: mt-experienceNew ReleasesBeanProxy: BeanProxy 3.0: BeanProxy is a C# (.NET 3.5) library housing classes that facilitates unit testing. Any non-static, public interface/class or abstract class can be...Blueset Studio Opensource Projects: 蓝色之风记事本 0.2 Alpha: 一个超级Bug版本……CSharp Intellisense: V2.1: - Bug fix (Pascal Casing)DioM2D: DioM2D0.01: http://www.dragonsinourmidst.com/forums/showthread.php?p=690058#post690058Ethical Hacking ASP.NET: Version 1.0.0.1: This is the initial release of the project. Read more about the available tests and features on the Documentation tab. You need the full .NET Frame...Event Scavenger: Collector service update - version 3.2.4: Added check if the database connection string is set up in the config file.Feature Builder Guidance Extensions: FBGX-Binaries: This release consists of a zip file containing all the VSIXs resulting from building each of the FBGX packages found here as source. This will mak...Floe IRC Client: Floe IRC Client 2010-05 R2: - Detaching windows (right click on the tabs to detach them) - Highlight lines with your nick or other patterns - Fixed several bugs - Tabs can now...Free language translator and file converter: Free Language Translator 1.96: Fixed some minor bugs and improved the UI a bit. If you can not install the msi file you might be missing some prerequisites. You can try running t...Geocache Downloader: release 1.0: This is the first release.kp.net: Alpha release is avalable: The goal of this alpha release is to try the code in some production scenarios and find out what features should be tuned.Live-Exchange Calendar Sync: Live-Exchange Calendar Sync: Live-Exchange Calendar Sync Beta May 14, 2010 release of Live-Exchange Calendar Sync 1.0 BETA. (Version 45334) Getting StartedInfo about installat...MAPILab Explorer for SharePoint: MAPILab Explorer for SharePoint ver 2.1.1: 1) Small bug fixed that appears on first start (when earliers versions wasn't installed). How to install:Download ZIP file and extract it on Sha...Microsoft Office Document Security: MODS 4 WORD (SOURCE INCLUDED): Includes Source CodeMoonyDesk (windows desktop widgets): MoonyDesk Alpha: MoonyDesk Alpha (some memory improvements)OnTopReplica: Release 2.9.3: Some bugfixes and improvements. Czech translation added (thanks René Mihula).OutSync: OutSync v1.0.100.0: OutSync v1.0.100.0 is the final release by Mel before the move to CodePlex. I have tested it on Windows 7 32bit and 64bit with Office 2007 and it ...Quick Save Images, Clipboard save to file, Quick save, bmp, png, jpeg, Image: Clipsa v 0.1: Download and extract to any place 2 files - clipSa.exe and clipSa.exe.config Run clipSa.exe. That's all.ResHelper Manager: ResHelperManager: List of changes applied to this version of ResHelper is included in main download zip package. Example sourcesIn Source Code tab are sources of De...Rx Contrib: V1.3: - Bug Fix - BufferWithTimeOrCount with flexible time period setting when ever the time period elapsed...SharePoint DVK Integration: SharePoint 2007 DVK integration v1.0.3: Fixes Fixed default field bindings. I rebound too many fields on every page load. Fixed extension replacing on creating target url (threw it out)...ShoutcastStast for DotNetNuke: DNN_ShoutcastStats alpha 05.00.495: First Alpha release of ShoutcastStats Module for DotNetNuke This first alpha version of the ShoutcastStats Module for DotNetNuke is still in devel...SilverPart 2.1: SilverPart 2.1: SilverPart 2.1 This interim release fixes some major bugs related to Firefox and anonymous access. - Fix for Issue ID 4005 - SilverPart does not w...sMAPtool: sMAPedit v0.7c (Base Release with Maps): Fixed: force a gargabe collection update to prevent pictureBox's memory leak Added: essential map pack with all basic maps in jpg format Added:...SQL Trim: Trim: Initial releaseSSIS Multiple Hash: Multiple Hash V1.2.1: This is version 1.2.1 of the Multiple Hash SSIS Component. It supports SQL 2005 and SQL 2008, although you have to download the correct install pa...StreamInsight Yahoo Finance input adapter example: StockTicker_v1_0_RTM: Updated for StreamInsight RTM.Update Controls .NET: 2.1.0.0: Automatic dependency management for WPF and Silverlight data binding. This release combines both the WPF and Silverlight assemblies into one insta...VCC: Latest build, v2.1.30514.0: Automatic drop of latest buildMost Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)patterns & practices – Enterprise LibraryMicrosoft SQL Server Community & SamplesPHPExcelASP.NETMost Active Projectspatterns & practices – Enterprise LibraryMirror Testing SystemRawrPHPExcelBlogEngine.NETMicrosoft Biology FoundationCustomer Portal Accelerator for Microsoft Dynamics CRMWindows Azure Command-line Tools for PHP DevelopersShake - C# MakeStyleCop

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• Using Unity – Part 6

  - by nmarun

  This is the last of the ‘Unity’ series and I’ll be talking about generics here. If you’ve been following the previous articles, you must have noticed that I’m just adding more and more ‘Product’ classes to the project. I’ll change that trend in this blog where I’ll be adding an ICaller interface and a Caller class. 1: public interface ICaller<T> where T : IProduct 2: { 3: string CallMethod<T>(string typeName); 4: } 5:  6: public class Caller<T> : ICaller<T> where T:IProduct 7: { 8: public string CallMethod<T>(string typeName) 9: { 10: //... 11: } 12: } We’ll fill-in the implementation of the CallMethod in a few, but first, here’s what we’re going to do: create an instance of the Caller class pass it the IProduct as a generic parameter in the CallMethod method, we’ll use Unity to dynamically create an instance of IProduct implemented object I need to add the config information for ICaller and Caller types. 1: <typeAlias alias="ICaller`1" type="ProductModel.ICaller`1, ProductModel" /> 2: <typeAlias alias="Caller`1" type="ProductModel.Caller`1, ProductModel" /> The .NET Framework’s convention to express generic types is ICaller`1, where the digit following the "`" matches the number of types contained in the generic type. So a generic type that contains 4 types contained in the generic type would be declared as: 1: <typeAlias alias="Caller`4" type="ProductModel.Caller`4, ProductModel" /> On my .aspx page, I have the following UI design: 1: <asp:RadioButton ID="LegacyProduct" Text="Product" runat="server" GroupName="ProductWeb" 2: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 3: <br /> 4: <asp:RadioButton ID="NewProduct" Text="Product 2" runat="server" GroupName="ProductWeb" 5: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 6: <br /> 7: <asp:RadioButton ID="ComplexProduct" Text="Product 3" runat="server" GroupName="ProductWeb" 8: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> 9: <br /> 10: <asp:RadioButton ID="ArrayConstructor" Text="Product 4" runat="server" GroupName="ProductWeb" 11: AutoPostBack="true" OnCheckedChanged="RadioButton_CheckedChanged" /> Things to note here are that all these radio buttons belong to the same GroupName => only one of these four can be clicked. Next, all four controls postback to the same ‘OnCheckedChanged’ event and lastly the ID’s point to named types of IProduct (already added to the web.config file). 1: <type type="IProduct" mapTo="Product" name="LegacyProduct" /> 2:  3: <type type="IProduct" mapTo="Product2" name="NewProduct" /> 4:  5: <type type="IProduct" mapTo="Product3" name="ComplexProduct"> 6: ... 7: </type> 8:  9: <type type="IProduct" mapTo="Product4" name="ArrayConstructor"> 10: ... 11: </type> In my calling code, I see which radio button was clicked, pass that as an argument to the CallMethod method. 1: protected void RadioButton_CheckedChanged(object sender, EventArgs e) 2: { 3: string typeName = ((RadioButton)sender).ID; 4: ICaller<IProduct> caller = unityContainer.Resolve<ICaller<IProduct>>(); 5: productDetailsLabel.Text = caller.CallMethod<IProduct>(typeName); 6: } What’s basically happening here is that the ID of the control gets passed on to the typeName which will be one of “LegacyProduct”, “NewProduct”, “ComplexProduct” or “ArrayConstructor”. I then create an instance of an ICaller and pass the typeName to it. Now, we’ll fill in the blank for the CallMethod method (sorry for the naming guys). 1: public string CallMethod<T>(string typeName) 2: { 3: IUnityContainer unityContainer = HttpContext.Current.Application["UnityContainer"] as IUnityContainer; 4: T productInstance = unityContainer.Resolve<T>(typeName); 5: return ((IProduct)productInstance).WriteProductDetails(); 6: } This is where I’ll resolve the IProduct by passing the type name and calling the WriteProductDetails() method. With all things in place, when I run the application and choose different radio buttons, the output should look something like below:          Basically this is how generics come to play in Unity. Please see the code I’ve used for this here. This marks the end of the ‘Unity’ series. I’ll definitely post any updates that I find, but for now I don’t have anything planned.

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• The last MVVM you'll ever need?

  - by Nuri Halperin

  As my MVC projects mature and grow, the need to have some omnipresent, ambient model properties quickly emerge. The application no longer has only one dynamic pieced of data on the page: A sidebar with a shopping cart, some news flash on the side – pretty common stuff. The rub is that a controller is invoked in context of a single intended request. The rest of the data, even though it could be just as dynamic, is expected to appear on it's own. There are many solutions to this scenario. MVVM prescribes creating elaborate objects which expose your new data as a property on some uber-object with more properties exposing the "side show" ambient data. The reason I don't love this approach is because it forces fairly acute awareness of the view, and soon enough you have many MVVM objects laying around, and views have to start doing null-checks in order to ensure you really supplied all the values before binding to them. Ick. Just as unattractive is the ViewData dictionary. It's not strongly typed, and in both this and the MVVM approach someone has to populate these properties – n'est pas? Where does that live? With MVC2, we get the formerly-futures  feature Html.RenderAction(). The feature allows you plant a line in a view, of the format: <% Html.RenderAction("SessionInterest", "Session"); %> While this syntax looks very clean, I can't help being bothered by it. MVC was touting a very strong separation of concerns, the Model taking on the role of the business logic, the controller handling route and performing minimal view-choosing operations and the views strictly focused on rendering out angled-bracket tags. The RenderAction() syntax has the view calling some controller and invoking it inline with it's runtime rendering. This – to my taste – embeds too much  knowledge of controllers into the view's code – which was allegedly forbidden.  The one way flow "Controller Receive Data –> Controller invoke Model –> Controller select view –> Controller Hand data to view" now gets a "View calls controller and gets it's own data" which is not so one-way anymore. Ick. I toyed with some other solutions a bit, including some base controllers, special view classes etc. My current favorite though is making use of the ExpandoObject and dynamic features with C# 4.0. If you follow Phil Haack or read a bit from David Heyden you can see the general picture emerging. The game changer is that using the new dynamic syntax, one can sprout properties on an object and make use of them in the view. Well that beats having a bunch of uni-purpose MVVM's any day! Rather than statically exposed properties, we'll just use the capability of adding members at runtime. Armed with new ideas and syntax, I went to work: First, I created a factory method to enrich the focuse object: public static class ModelExtension { public static dynamic Decorate(this Controller controller, object mainValue) { dynamic result = new ExpandoObject(); result.Value = mainValue; result.SessionInterest = CodeCampBL.SessoinInterest(); result.TagUsage = CodeCampBL.TagUsage(); return result; } } This gives me a nice fluent way to have the controller add the rest of the ambient "side show" items (SessionInterest, TagUsage in this demo) and expose them all as the Model: public ActionResult Index() { var data = SyndicationBL.Refresh(TWEET_SOURCE_URL); dynamic result = this.Decorate(data); return View(result); } So now what remains is that my view knows to expect a dynamic object (rather than statically typed) so that the ASP.NET page compiler won't barf: <%@ Page Language="C#" Title="Ambient Demo" MasterPageFile="~/Views/Shared/Ambient.Master" Inherits="System.Web.Mvc.ViewPage<dynamic>" %> Notice the generic ViewPage<dynamic>. It doesn't work otherwise. In the page itself, Model.Value property contains the main data returned from the controller. The nice thing about this, is that the master page (Ambient.Master) also inherits from the generic ViewMasterPage<dynamic>. So rather than the page worrying about all this ambient stuff, the side bars and panels for ambient data all reside in a master page, and can be rendered using the RenderPartial() syntax: <% Html.RenderPartial("TagCloud", Model.SessionInterest as Dictionary<string, int>); %> Note here that a cast is necessary. This is because although dynamic is magic, it can't figure out what type this property is, and wants you to give it a type so its binder can figure out the right property to bind to at runtime. I use as, you can cast if you like. So there we go – no violation of MVC, no explosion of MVVM models and voila – right? Well, I could not let this go without a tweak or two more. The first thing to improve, is that some views may not need all the properties. In that case, it would be a waste of resources to populate every property. The solution to this is simple: rather than exposing properties, I change d the factory method to expose lambdas - Func<T> really. So only if and when a view accesses a member of the dynamic object does it load the data. public static class ModelExtension { // take two.. lazy loading! public static dynamic LazyDecorate(this Controller c, object mainValue) { dynamic result = new ExpandoObject(); result.Value = mainValue; result.SessionInterest = new Func<Dictionary<string, int>>(() => CodeCampBL.SessoinInterest()); result.TagUsage = new Func<Dictionary<string, int>>(() => CodeCampBL.TagUsage()); return result; } } Now that lazy loading is in place, there's really no reason not to hook up all and any possible ambient property. Go nuts! Add them all in – they won't get invoked unless used. This now requires changing the signature of usage on the ambient properties methods –adding some parenthesis to the master view: <% Html.RenderPartial("TagCloud", Model.SessionInterest() as Dictionary<string, int>); %> And, of course, the controller needs to call LazyDecorate() rather than the old Decorate(). The final touch is to introduce a convenience method to the my Controller class , so that the tedium of calling Decorate() everywhere goes away. This is done quite simply by adding a bunch of methods, matching View(object), View(string,object) signatures of the Controller class: public ActionResult Index() { var data = SyndicationBL.Refresh(TWEET_SOURCE_URL); return AmbientView(data); } //these methods can reside in a base controller for the solution: public ViewResult AmbientView(dynamic data) { dynamic result = ModelExtension.LazyDecorate(this, data); return View(result); } public ViewResult AmbientView(string viewName, dynamic data) { dynamic result = ModelExtension.LazyDecorate(this, data); return View(viewName, result); } The call to AmbientView now replaces any call the View() that requires the ambient data. DRY sattisfied, lazy loading and no need to replace core pieces of the MVC pipeline. I call this a good MVC day. Enjoy!

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• AdvancedFormatProvider: Making string.format do more

  - by plblum

  When I have an integer that I want to format within the String.Format() and ToString(format) methods, I’m always forgetting the format symbol to use with it. That’s probably because its not very intuitive. Use {0:N0} if you want it with group (thousands) separators. text = String.Format("{0:N0}", 1000); // returns "1,000"   int value1 = 1000; text = value1.ToString("N0"); Use {0:D} or {0:G} if you want it without group separators. text = String.Format("{0:D}", 1000); // returns "1000"   int value2 = 1000; text2 = value2.ToString("D"); The {0:D} is especially confusing because Microsoft gives the token the name “Decimal”. I thought it reasonable to have a new format symbol for String.Format, "I" for integer, and the ability to tell it whether it shows the group separators. Along the same lines, why not expand the format symbols for currency ({0:C}) and percent ({0:P}) to let you omit the currency or percent symbol, omit the group separator, and even to drop the decimal part when the value is equal to the whole number? My solution is an open source project called AdvancedFormatProvider, a group of classes that provide the new format symbols, continue to support the rest of the native symbols and makes it easy to plug in additional format symbols. Please visit https://github.com/plblum/AdvancedFormatProvider to learn about it in detail and explore how its implemented. The rest of this post will explore some of the concepts it takes to expand String.Format() and ToString(format). AdvancedFormatProvider benefits: Supports {0:I} token for integers. It offers the {0:I-,} option to omit the group separator. Supports {0:C} token with several options. {0:C-$} omits the currency symbol. {0:C-,} omits group separators, and {0:C-0} hides the decimal part when the value would show “.00”. For example, 1000.0 becomes “$1000” while 1000.12 becomes “$1000.12”. Supports {0:P} token with several options. {0:P-%} omits the percent symbol. {0:P-,} omits group separators, and {0:P-0} hides the decimal part when the value would show “.00”. For example, 1 becomes “100 %” while 1.1223 becomes “112.23 %”. Provides a plug in framework that lets you create new formatters to handle specific format symbols. You register them globally so you can just pass the AdvancedFormatProvider object into String.Format and ToString(format) without having to figure out which plug ins to add. text = String.Format(AdvancedFormatProvider.Current, "{0:I}", 1000); // returns "1,000" text2 = String.Format(AdvancedFormatProvider.Current, "{0:I-,}", 1000); // returns "1000" text3 = String.Format(AdvancedFormatProvider.Current, "{0:C-$-,}", 1000.0); // returns "1000.00" The IFormatProvider parameter Microsoft has made String.Format() and ToString(format) format expandable. They each take an additional parameter that takes an object that implements System.IFormatProvider. This interface has a single member, the GetFormat() method, which returns an object that knows how to convert the format symbol and value into the desired string. There are already a number of web-based resources to teach you about IFormatProvider and the companion interface ICustomFormatter. I’ll defer to them if you want to dig more into the topic. The only thing I want to point out is what I think are implementation considerations. Why GetFormat() always tests for ICustomFormatter When you see examples of implementing IFormatProviders, the GetFormat() method always tests the parameter against the ICustomFormatter type. Why is that? public object GetFormat(Type formatType) { if (formatType == typeof(ICustomFormatter)) return this; else return null; } The value of formatType is already predetermined by the .net framework. String.Format() uses the StringBuilder.AppendFormat() method to parse the string, extracting the tokens and calling GetFormat() with the ICustomFormatter type. (The .net framework also calls GetFormat() with the types of System.Globalization.NumberFormatInfo and System.Globalization.DateTimeFormatInfo but these are exclusive to how the System.Globalization.CultureInfo class handles its implementation of IFormatProvider.) Your code replaces instead of expands I would have expected the caller to pass in the format string to GetFormat() to allow your code to determine if it handles the request. My vision would be to return null when the format string is not supported. The caller would iterate through IFormatProviders until it finds one that handles the format string. Unfortunatley that is not the case. The reason you write GetFormat() as above is because the caller is expecting an object that handles all formatting cases. You are effectively supposed to write enough code in your formatter to handle your new cases and call .net functions (like String.Format() and ToString(format)) to handle the original cases. Its not hard to support the native functions from within your ICustomFormatter.Format function. Just test the format string to see if it applies to you. If not, call String.Format() with a token using the format passed in. public string Format(string format, object arg, IFormatProvider formatProvider) { if (format.StartsWith("I")) { // handle "I" formatter } else return String.Format(formatProvider, "{0:" + format + "}", arg); } Formatters are only used by explicit request Each time you write a custom formatter (implementer of ICustomFormatter), it is not used unless you explicitly passed an IFormatProvider object that supports your formatter into String.Format() or ToString(). This has several disadvantages: Suppose you have several ICustomFormatters. In order to have all available to String.Format() and ToString(format), you have to merge their code and create an IFormatProvider to return an instance of your new class. You have to remember to utilize the IFormatProvider parameter. Its easy to overlook, especially when you have existing code that calls String.Format() without using it. Some APIs may call String.Format() themselves. If those APIs do not offer an IFormatProvider parameter, your ICustomFormatter will not be available to them. The AdvancedFormatProvider solves the first two of these problems by providing a plug-in architecture.

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• When OneTug Just Isn&rsquo;t Enough&hellip;

  - by onefloridacoder

  I stole that from the back of a T-shirt I saw at the Orlando Code Camp 2010.  This was my first code camp and my first time volunteering for an event like this as well.  It was an awesome day.  I cannot begin to count the “aaahh”, “I did-not-know I could do that”, in the crowds and for myself.  I think it was a great day of learning for everyone at all levels.  All of the presenters were different and provided great insights into the topics they were presenting.  Here’s a list of the ones that I attended. KodeFuGuru, “Pirates vs. Ninjas” He touched on many good topics to relax some of the ways we think when we are writing out code, and still looks good, readable, etc.  As he pointed out in all of his examples, we might not always realize everything that’s going on under the covers.  He exposed a bug in his own code, and verbalized the mental gymnastics he went through when he knew there was something wrong with one of his IEnumerable implementations.  For me, it was great to hear that someone else labors over these gut reactions to code quickly snapped together, to the point that we rush to the refactor stage to fix what’s bothering us – and learn.  He has some content on extension methods that was very interesting.  My “that is so cool” moment was when he swapped out AddEntity method on an entity class and used a With extension method instead.  Some of the LINQ scales fell off my eyes at that moment, and I realized my own code could be a lot more powerful (and readable) if incorporate a few of these examples at the appropriate times.  And he cautioned as well… “don’t go crazy with this stuff”, there’s a place and time for everything.  One of his examples demo’d toward the end of the talk is on his sight where he’s chaining methods together, cool stuff. Quotes I liked: “Extension Methods - Extension methods to put features back on the model type, without impacting the type.” “Favor Declarative Code” – Check out the ? and ?? operators if you’re not already using them. “Favor Fluent Code” “Avoid Pirate Ninja Zombies!  If you see one run!” I’m definitely going to be looking at “Extract Projection” when I get into VS2010. BDD 101 – Sean Chambers http://github.com/schambers This guy had a whole host of gremlins against him, final score Sean 5, Gremlins 1.  He ran the code samples from his github repo  in the code github code viewer since the PC they school gave him to use didn’t have VS installed. He did a great job of converting the grammar between BDD and TDD, and how this style of development can be used in integration tests as well as the different types of gated builds on a CI box – he didn’t go into a discussion around CI, but we could infer that it could work. Like when we use WSSF, it does cause a class explosion to happen however the amount of code per class it limit to just covering the concern at hand – no more, no less.  As in “When I as a <Role>, expect {something} to happen, because {}”  This keeps us (the developer) from gold plating our solutions and creating less waste.  He basically keeps the code that prove out the requirement to two lines of code.  Nice. He uses SpecUnit to merge this grammar into his .NET projects and gave an overview on how this ties into writing his own BDD tests.  Some folks were familiar with Given / When / Then as story acceptance criteria and here’s how he mapped it: “Given <Context>  When <Something Happens> Then <I expect...>”  There are a few base classes and overrides in the SpecUnit framework that help with setting up the context for each test which looked very handy. Successfully Running Your Own Coding Business The speaker ran through a list of items that sounded like common sense stuff LLC, banking, separating expenses, etc.  Then moved into role playing with business owners and an ISV.  That was pretty good stuff, it pays to be a good listener all of the time even if your client is sitting on the other side of the phone tearing you head off for you – but that’s all it is, and get used to it its par for the course.  Oh, yeah always answer the phone was one simple thing that you can do to move  your business forward.  But like Cory Foy tweeted this week, “If you owe me a lot of money, don’t have a message that says your away for five weeks skiing in Colorado.”  Lots of food for thought that’s on my list of “todo’s and to-don’ts”. Speaker Idol Next, I had the pleasure of helping Russ Fustino tape this part of Code Camp as my primary volunteer opportunity that day.  You remember Russ, “know the code” from the awesome Russ’ Tool Shed series.  He did a great job orchestrating and capturing the Speaker Idol finals.   So I didn’t actually miss any sessions, but was able to see three back to back in one setting.  The idol finalists gave a 10 minute talk and very deep subjects, but different styles of talks.  No one walked away empty handed for jobs very well done.  Russ has details on his site.  The pictures and  video captured is supposed to be published on Channel 9 at a later date.  It was also a valuable experience to see what makes technical speakers effective in their talks.  I picked up quite a few speaking tips from what I heard from the judges and contestants. Design For Developers – Diane Leeper If you are a great developer, you’re probably a lousy designer.  Diane didn’t come to poke holes in what we think we can do with UI layout and design, but she provided some tools we can use to figure out metaphors for visualizing data.  If you need help with that check out Silverlight Pivot – that’s what she was getting at.  I was first introduced to her at one of John Papa’s talks last year at a Lakeland User Group meeting and she’s very passionate about design.  She was able to discuss different elements of Pivot, while to a developer is just looked cool. I believe she was providing the deck from her talk to folks after her talk, so send her an email if you’re interested.   She says she can talk about design for hours and hours – we all left that session believing her.   Rinse and Repeat Orlando Code Camp 2010 was awesome, and would totally do it again.  There were lots of folks from my shop there, and some that have left my shop to go elsewhere.  So it was a reunion of sorts and a great celebration for the simple fact that its great to be a developer and there’s a community that supports and recognizes it as well.  The sponsors were generous and the organizers were very tired, namely Esteban Garcia and Will Strohl who were responsible for making a lot of this magic happen.  And if you don’t believe me, check out the chatter on Twitter.

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• Easier ASP.NET MVC Routing

  - by Steve Wilkes

  I've recently refactored the way Routes are declared in an ASP.NET MVC application I'm working on, and I wanted to share part of the system I came up with; a really easy way to declare and keep track of ASP.NET MVC Routes, which then allows you to find the name of the Route which has been selected for the current request. Traditional MVC Route Declaration Traditionally, ASP.NET MVC Routes are added to the application's RouteCollection using overloads of the RouteCollection.MapRoute() method; for example, this is the standard way the default Route which matches /controller/action URLs is created: routes.MapRoute(     "Default",     "{controller}/{action}/{id}",     new { controller = "Home", action = "Index", id = UrlParameter.Optional }); The first argument declares that this Route is to be named 'Default', the second specifies the Route's URL pattern, and the third contains the URL pattern segments' default values. To then write a link to a URL which matches the default Route in a View, you can use the HtmlHelper.RouteLink() method, like this: @ this.Html.RouteLink("Default", new { controller = "Orders", action = "Index" }) ...that substitutes 'Orders' into the {controller} segment of the default Route's URL pattern, and 'Index' into the {action} segment. The {Id} segment was declared optional and isn't specified here. That's about the most basic thing you can do with MVC routing, and I already have reservations: I've duplicated the magic string "Default" between the Route declaration and the use of RouteLink(). This isn't likely to cause a problem for the default Route, but once you get to dozens of Routes the duplication is a pain. There's no easy way to get from the RouteLink() method call to the declaration of the Route itself, so getting the names of the Route's URL parameters correct requires some effort. The call to MapRoute() is quite verbose; with dozens of Routes this gets pretty ugly. If at some point during a request I want to find out the name of the Route has been matched.... and I can't. To get around these issues, I wanted to achieve the following: Make declaring a Route very easy, using as little code as possible. Introduce a direct link between where a Route is declared, where the Route is defined and where the Route's name is used, so I can use Visual Studio's Go To Definition to get from a call to RouteLink() to the declaration of the Route I'm using, making it easier to make sure I use the correct URL parameters. Create a way to access the currently-selected Route's name during the execution of a request. My first step was to come up with a quick and easy syntax for declaring Routes. 1 . An Easy Route Declaration Syntax I figured the easiest way of declaring a route was to put all the information in a single string with a special syntax. For example, the default MVC route would be declared like this: "{controller:Home}/{action:Index}/{Id}*" This contains the same information as the regular way of defining a Route, but is far more compact: The default values for each URL segment are specified in a colon-separated section after the segment name The {Id} segment is declared as optional simply by placing a * after it That's the default route - a pretty simple example - so how about this? routes.MapRoute(     "CustomerOrderList",     "Orders/{customerRef}/{pageNo}",     new { controller = "Orders", action = "List", pageNo = UrlParameter.Optional },     new { customerRef = "^[a-zA-Z0-9]+$", pageNo = "^[0-9]+$" }); This maps to the List action on the Orders controller URLs which: Start with the string Orders/ Then have a {customerRef} set of characters and numbers Then optionally a numeric {pageNo}. And again, it’s quite verbose. Here's my alternative: "Orders/{customerRef:^[a-zA-Z0-9]+$}/{pageNo:^[0-9]+$}*->Orders/List" Quite a bit more brief, and again, containing the same information as the regular way of declaring Routes: Regular expression constraints are declared after the colon separator, the same as default values The target controller and action are specified after the -> The {pageNo} is defined as optional by placing a * after it With an appropriate parser that gave me a nice, compact and clear way to declare routes. Next I wanted to have a single place where Routes were declared and accessed. 2. A Central Place to Declare and Access Routes I wanted all my Routes declared in one, dedicated place, which I would also use for Route names when calling RouteLink(). With this in mind I made a single class named Routes with a series of public, constant fields, each one relating to a particular Route. With this done, I figured a good place to actually declare each Route was in an attribute on the field defining the Route’s name; the attribute would parse the Route definition string and make the resulting Route object available as a property. I then made the Routes class examine its own fields during its static setup, and cache all the attribute-created Route objects in an internal Dictionary. Finally I made Routes use that cache to register the Routes when requested, and to access them later when required. So the Routes class declares its named Routes like this: public static class Routes{     [RouteDefinition("Orders/{customerName}->Orders/Index")]     public const string OrdersCustomerIndex = "OrdersCustomerIndex";     [RouteDefinition("Orders/{customerName}/{orderId:^([0-9]+)$}->Orders/Details")]     public const string OrdersDetails = "OrdersDetails";     [RouteDefinition("{controller:Home}*/{action:Index}*")]     public const string Default = "Default"; } ...which are then used like this: @ this.Html.RouteLink(Routes.Default, new { controller = "Orders", action = "Index" }) Now that using Go To Definition on the Routes.Default constant takes me to where the Route is actually defined, it's nice and easy to quickly check on the parameter names when using RouteLink(). Finally, I wanted to be able to access the name of the current Route during a request. 3. Recovering the Route Name The RouteDefinitionAttribute creates a NamedRoute class; a simple derivative of Route, but with a Name property. When the Routes class examines its fields and caches all the defined Routes, it has access to the name of the Route through the name of the field against which it is defined. It was therefore a pretty easy matter to have Routes give NamedRoute its name when it creates its cache of Routes. This means that the Route which is found in RequestContext.RouteData.Route is now a NamedRoute, and I can recover the Route's name during a request. For visibility, I made NamedRoute.ToString() return the Route name and URL pattern, like this: The screenshot is from an example project I’ve made on bitbucket; it contains all the named route classes and an MVC 3 application which demonstrates their use. I’ve found this way of defining and using Routes much tidier than the default MVC system, and you find it useful too

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• Speaker at the German Visual FoxPro Developer Conference 2004

  The following is an excerpt from the UniversalThread conference coverage of the German Visual FoxPro Developer Conference 2004 written by Hans-Otto Lochmann, Armin Neudert and myself. TRACK Active FoxPro Pages Back in 1996 Peter Herzog invented a FoxPro based solution to provide intranet capabilities for one of his customers. Nearly at the same time Rick Strahl had the same task and created WestWind Web Connection (WWWC). The aspect that developers have to have a full Visual FoxPro development environment to create WWWC solutions was the starting point of a "personal sportive competition" of Peter to write his own solution. But the main aspect has to be that it doesn't rely on a full VFP version in order to run. The VFP runtime should enough and the source code has to be compiled and interpreted on the fly. So, as Microsoft released Active Server Pages a name for Peter's solution was found: Active FoxPro Pages (AFP). During the years many drawbacks, design aspects as well as technological hassles forced ProLib Software to refactor the product. This way many limits like DCOM configuration, file-based information transfer between Web server and AFP, missing features (like upload forms or other Web servers than IIS) and extensibility were eliminated. As a consequence ProLib Software decided to rewrite Active FoxPro Pages in mid of 2002 completely. Christof Wollenhaupt, before his marriage known as Christof Lange, and Jochen Kirstätter had to solve this task. AFP 3.0 was officially released at German Devcon in November 2002. Today AFP has six distributors world-wide and there is a lot more information available online than before version 3.0. Directly after a short welcome speech by Rainer Becker, Jochen Kirstätter - aka JoKi - opened today's AFP track and introduced the basic concepts how Active FoxPro Pages works in general, explained the AFP terminilogy and every single component, and presented a small Walk-Through about how to write an AFP-based Web solution. Actually his presentation slides themselves were an AFP Web application. This way it was easy to integrate accompanying AFP samples on the fly. Additionally it was shown that no Visual FoxPro development environment is needed to create a Web application. A simple text editor like NotePad or any WYSIWYG editor on the market is usable to fullfil customer's requirements.Welcome at least two new speakers - Nina Schwanzer and Bernhard Reiter. Both are working at ProLib Software and this year's conference is their first time as speakers. And they did their job very well. The whole session was kind of a "ping pong" game and those two complemented each other to keep the audience in tension. First, they described typical requirements a modern desktop application should fullfil - online registration and activation, auto-update capabilities, or even frontend to administer a Web application on a remote system via internet, and explained how possible solutions like Web Services (using the SOAP interface), DCOM, and even .NET might solve those requirements. But any of those ways has different drawbacks like complicated installation or configuration, or extraordinary download sizes. Next, they introduced a technology they developed and used in a customer's project: Active FoxPro Pages Remote Procedure Call (AFP RPC). [...]   In the next session JoKi described how to extend Active FoxPro Pages. On the one hand AFP provides a plugin interface, and on the other hand any addon for Visual FoxPro might be usable as well. During the first half he spoke about the plugin interface and wrote live a new AFP extension - the Devcon plugin. Later he questioned any former step and showed that a single AFP document may solve the problem as well. So, developing extensions is only interesting if they are re-usable and generic. At the end he talked about multiple interfaces for the same business logic. For instance plain VFP class, COM server and .NET integration. Currently there are several specialized AFP extensions for sending mail, for using cryptographic routines (ie. based on .NET classes), or enhanced methods to handle HTML/XML strings.Rainer Becker and Peter Herzog introduced a new development for Visual Extend (VFX) - an AFP form builder. With this builder creating an AFP Web form designed with Visual FoxPro's form designer was a matter of seconds. The builder itself is currently in pre-release status and will be part of the VFX framework in the future. It was very impressive to see that the whole design of a form as well as most parts of its functionality were exported to a combination of HTML, JavaScript and Active FoxPro Pages. At half-time Jürgen "wOOdy" Wondzinski and JoKi changed places with Rainer and Peter, and presented some Web solutions in AFP. [...] Visual FoxPro 9.0 und Linux Is Linux still a topic for Visual FoxPro developers based on the activities during this year? In his session Jochen Kirstätter - aka JoKi - went not through the technical steps and requirements on how to setup and run FoxPro on a Linux client. Instead, he explained what Linux actually is, and talked about the high variety of distributions. In fact there are a lot of distributions around but since some several years there are some specialized ones available: Live Distributions (aka LiveCDs).The intension of LiveCDs is to run a full-featured Linux operating system on any personal computer directly from a bootable medium, like CD, DVD, or even USB memory stick, without installation on a hard disk. One of the first Linux LiveCDs was made by Klaus Knopper and is well-known as Knoppix. Today, many other LiveCDs are based on the concepts of Knoppix. During the session Jochen booted Morphix, a very light-weighted LiveCD, on his notebook, and actually showed the attendees that testing and playing around with Linux is absolutely easy. Running a text processing application swept away most of the contrary aspects the audience had. Okay, where is the part about FoxPro? Well, there are several scenarios a customer might require usage of Linux, and actually with all of them FoxPro could deal with. I guess that one of the more common ones is the situation that a customer has a heterogeneous intranet with Windows clients and Linux servers, i.e. Windows XP Professional and any Linux distribution on their servers. Even in this scenario there are two variants hidden! Why? Well, on the one hand there is a software package called Samba, that provides Windows server capabilities to a Linux system, and on the other hand there are several SQL servers for Linux, like PostgreSQL, DB2 and MySQL. Either way, FoxPro is able to deal with these scenarios, but you as developer have to know what you are talking about with your customers. And even if there's no Windows operating system, you are able to provide a FoxPro-based solution. Using the wine library - wine stands for Wine Is Not an Emulator - you are able to run your VFP applications on Linux clients, too; but not without reading VFP's EULA. Licenses were also part the session, and Jochen discussed the meaning of Open Source and its misunderstanding throughout most developers. Open Source does not mean that it's without a fee. Instead, it stands for access to the source code of an application or tool. And, VFP itself is one of the best samples to explain Open Source due to fact that since years, VFP is shipped with the xSource.zip archive. [...]

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• Generate Strongly Typed Observable Events for the Reactive Extensions for .NET (Rx)

  - by Bobby Diaz

  I must have tried reading through the various explanations and introductions to the new Reactive Extensions for .NET before the concepts finally started sinking in.  The article that gave me the ah-ha moment was over on SilverlightShow.net and titled Using Reactive Extensions in Silverlight.  The author did a good job comparing the "normal" way of handling events vs. the new "reactive" methods. Admittedly, I still have more to learn about the Rx Framework, but I wanted to put together a sample project so I could start playing with the new Observable and IObservable<T> constructs.  I decided to throw together a whiteboard application in Silverlight based on the Drawing with Rx example on the aforementioned article.  At the very least, I figured I would learn a thing or two about a new technology, but my real goal is to create a fun application that I can share with the kids since they love drawing and coloring so much! Here is the code sample that I borrowed from the article: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp");       var draggingEvents = from pos in mouseMoveEvent                              .SkipUntil(mouseLeftButtonDown)                              .TakeUntil(mouseLeftButtonUp)                              .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) =>                                  new                                  {                                      X2 = cur.EventArgs.GetPosition(this).X,                                      X1 = prev.EventArgs.GetPosition(this).X,                                      Y2 = cur.EventArgs.GetPosition(this).Y,                                      Y1 = prev.EventArgs.GetPosition(this).Y                                  })).Repeat()                          select pos;       draggingEvents.Subscribe(p =>     {         Line line = new Line();         line.Stroke = new SolidColorBrush(Colors.Black);         line.StrokeEndLineCap = PenLineCap.Round;         line.StrokeLineJoin = PenLineJoin.Round;         line.StrokeThickness = 5;         line.X1 = p.X1;         line.Y1 = p.Y1;         line.X2 = p.X2;         line.Y2 = p.Y2;         this.LayoutRoot.Children.Add(line);     }); One thing that was nagging at the back of my mind was having to deal with the event names as strings, as well as the verbose syntax for the Observable.FromEvent<TEventArgs>() method.  I came up with a couple of static/helper classes to resolve both issues and also created a T4 template to auto-generate these helpers for any .NET type.  Take the following code from the above example: var mouseMoveEvent = Observable.FromEvent<MouseEventArgs>(this, "MouseMove"); var mouseLeftButtonDown = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonDown"); var mouseLeftButtonUp = Observable.FromEvent<MouseButtonEventArgs>(this, "MouseLeftButtonUp"); Turns into this with the new static Events class: var mouseMoveEvent = Events.Mouse.Move.On(this); var mouseLeftButtonDown = Events.Mouse.LeftButtonDown.On(this); var mouseLeftButtonUp = Events.Mouse.LeftButtonUp.On(this); Or better yet, just remove the variable declarations altogether:     var draggingEvents = from pos in Events.Mouse.Move.On(this)                              .SkipUntil(Events.Mouse.LeftButtonDown.On(this))                              .TakeUntil(Events.Mouse.LeftButtonUp.On(this))                              .Let(mm => mm.Zip(mm.Skip(1), (prev, cur) =>                                  new                                  {                                      X2 = cur.EventArgs.GetPosition(this).X,                                      X1 = prev.EventArgs.GetPosition(this).X,                                      Y2 = cur.EventArgs.GetPosition(this).Y,                                      Y1 = prev.EventArgs.GetPosition(this).Y                                  })).Repeat()                          select pos; The Move, LeftButtonDown and LeftButtonUp members of the Events.Mouse class are readonly instances of the ObservableEvent<TTarget, TEventArgs> class that provide type-safe access to the events via the On() method.  Here is the code for the class: using System; using System.Collections.Generic; using System.Linq;   namespace System.Linq {     /// <summary>     /// Represents an event that can be managed via the <see cref="Observable"/> API.     /// </summary>     /// <typeparam name="TTarget">The type of the target.</typeparam>     /// <typeparam name="TEventArgs">The type of the event args.</typeparam>     public class ObservableEvent<TTarget, TEventArgs> where TEventArgs : EventArgs     {         /// <summary>         /// Initializes a new instance of the <see cref="ObservableEvent"/> class.         /// </summary>         /// <param name="eventName">Name of the event.</param>         protected ObservableEvent(String eventName)         {             EventName = eventName;         }           /// <summary>         /// Registers the specified event name.         /// </summary>         /// <param name="eventName">Name of the event.</param>         /// <returns></returns>         public static ObservableEvent<TTarget, TEventArgs> Register(String eventName)         {             return new ObservableEvent<TTarget, TEventArgs>(eventName);         }           /// <summary>         /// Creates an enumerable sequence of event values for the specified target.         /// </summary>         /// <param name="target">The target.</param>         /// <returns></returns>         public IObservable<IEvent<TEventArgs>> On(TTarget target)         {             return Observable.FromEvent<TEventArgs>(target, EventName);         }           /// <summary>         /// Gets or sets the name of the event.         /// </summary>         /// <value>The name of the event.</value>         public string EventName { get; private set; }     } } And this is how it's used:     /// <summary>     /// Categorizes <see cref="ObservableEvents"/> by class and/or functionality.     /// </summary>     public static partial class Events     {         /// <summary>         /// Implements a set of predefined <see cref="ObservableEvent"/>s         /// for the <see cref="System.Windows.System.Windows.UIElement"/> class         /// that represent mouse related events.         /// </summary>         public static partial class Mouse         {             /// <summary>Represents the MouseMove event.</summary>             public static readonly ObservableEvent<UIElement, MouseEventArgs> Move =                 ObservableEvent<UIElement, MouseEventArgs>.Register("MouseMove");               // additional members omitted...         }     } The source code contains a static Events class with prefedined members for various categories (Key, Mouse, etc.).  There is also an Events.tt template that you can customize to generate additional event categories for any .NET type.  All you should have to do is add the name of your class to the types collection near the top of the template:     types = new Dictionary<String, Type>()     {         //{ "Microsoft.Maps.MapControl.Map, Microsoft.Maps.MapControl", null }         { "System.Windows.FrameworkElement, System.Windows", null },         { "Whiteboard.MainPage, Whiteboard", null }     }; The template is also a bit rough at this point, but at least it generates code that *should* compile.  Please let me know if you run into any issues with it.  Some people have reported errors when trying to use T4 templates within a Silverlight project, but I was able to get it to work with a little black magic...  You can download the source code for this project or play around with the live demo.  Just be warned that it is at a very early stage so don't expect to find much today.  I plan on adding alot more options like pen colors and sizes, saving, printing, etc. as time permits.  HINT: hold down the ESC key to erase! Enjoy! Additional Resources Using Reactive Extensions in Silverlight DevLabs: Reactive Extensions for .NET (Rx) Rx Framework Part III - LINQ to Events - Generating GetEventName() Wrapper Methods using T4

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• CodePlex Daily Summary for Saturday, March 27, 2010

  CodePlex Daily Summary for Saturday, March 27, 2010New ProjectsAlter gear SQL index Management: SQL Index management displays a list of indexes available for the chosen database and allows you to select an individual / group of indexes to be r...ASP League Ladder System: An ASP ladder / league system for online gaming league or real life leagues also.Augmented Reality Strategy Simulator: Augmented Reality Strategy Simulator is a software suite to promote computer aided strategy planning. Sports team can visualize their strategy usin...Boo syntax highlighting for Visual Studio 2010: Simple syntax hightlighting VSX add-in for Boo language in Visual Studio 2010.easySan: easySan zur einfachen Mitgliedsverwaltung im BRKFsUnit: FsUnit makes unit-testing with F# more enjoyable. It adds a special syntax to your favorite .NET testing framework.Laughing Dog XNA Framework: Laughing Dog is a simple to use, component based 2D framework for XNA game development. At present it is very early in development and as such is f...miniTodo: WPFでMVVMの練習にてきとうに作ったTODOアプリ 実用は無理です。My Common Library on .NET with CSharp: My Common Library on .NET with CSharp, it conclude database assecc, encrypt string, data caching, StringUtility, thank you for your view.Native code wrapping using c# : fsutil sparse commands: Ever thought about creating HUGE FILES for future use but felt bad for the wasted memory? Well, SPARSE FILES are the ANSWER! This FSUTIL SPARSE CO...Open SOA Platform: A centralized system for administering applications throught a SOA Enterprise Service Bus: Runtime environment (PROD, DEV, ...) , application and s...P-DBMS: Network and Database ProjectPraiseSight: PraiseSight is supposed to become a practical tool for churches to catalog an present their songs, lyrics and presentations on a beamer. The soluti...Pretty Good Frontend: Pretty Good Frontend is a sample frontend for ConfigMgr (SCCM) 2007 and MDT 2010 Zero Touch. S3Appender (Appender for Log4Net that Uses Amazon S3 For Storing Log Files): The S3Appender is a log4net appender that stores log events in either a MemoryStream or FileStream and sends them to S3 based on time intervals and...sEmit: sEmit (sms emitter) is an application written in C# which was built to send text messages. The project was founded in May 2009 by cansik. It works ...Silverlight RIA Tools: A tool set that generates a full RIA Solutions in Silverlightthommo cannon: Cannon for shooting down ThommosTianjin Polytechnic University Online Judge: Online Judge System Built on Microsoft technologies. Vision & Scope: A distributed OJ Solution on Windows and Cloud. Technologies used or planed...Tinare: Tinare is an byte encryption and decryption alogrithm. The input key is a string password.TinyPlug: Small Plugin Manager, written in C# Allows a project to define supported interfaces, and at runtime add plugins which support (inherit) these in...Utility niconv helps to convert text from one encoding to another: .NET implementation of GUN iconv console converter utility. The niconv program converts text from one encoding to another encoding. In the future r...WareFeed - Software Business Analytics: WareFeed is a simple but effective Software Business Analytics tool written in PHP and compatible others languages such as .NET, Java or Python. It...Y36API1: Semestralni projekt na Y36APINew ReleasesAlter gear SQL index Management: Setup 1.0.0: setup for first alpha releaseASP League Ladder System: ASPLeagueRelease_0_4_1: Release v 0.41Augmented Reality Strategy Simulator: Augmented Reality Strategy Simulator: Version 1.0 InstallerAutoAudit: AutoAudit 1.10e: Version 1.10e will be the final iteration of version 1 development. Version 2 will begin adding switches and options. Pleae email your suggestio...Boo syntax highlighting for Visual Studio 2010: Boo syntax VS 2010 - alpha: First release TODO: Multiline comments!Chargify.NET: Chargify.NET 0.6: Updated library, using Metered Components and updated Product information.Composer: V1.0.326.1000 Alpha: Initial Alpha release. Should be stable, with minor issues.CoNatural Components: CoNatural Components 1.6: Code fixes: Created helper classes to generate source code for type mapper/materializer. Fixed issue in optimized type materializer when loading ...CRM External View: 1.2: New Features in v1.2 release Password protected views. No more using Web Data Access role from v1. Filtering capabilities Caching for performan...Designit Video Embed Package: Release 1.1.0 beta1: You can now either have the video embeded directly in the template or have a preview in template that opens the video in a lightbox window.FsUnit: FsUnit 0.9.0 for NUnit: This release is for F# 2.0 and NUnit 2.5+.Laughing Dog XNA Framework: Laughing Dog 0.0.1: Laughing Dog - Alpla - v 0.0.1 First released version of the Laughing Dog framework.LiveUpload to Facebook: LiveUpload to Facebook 3.2: Version 3.2Become a fan on Facebook! Features Quickly and easily upload your photos and videos to Facebook, including any people tags added in Win...MapWindow6: MapWindow 6.0 msi March 26: This version adds the Join feature for creating a new "featureset" with attributes that are joined with attributes from a Excel data label named 'D...Mobile Broadband Logging Monitor: Mobile Broadband Logging Monitor 1.2.2: This edition supports: Newer and older editions of Birdstep Technology's EasyConnect HUAWEI Mobile Partner MWConn User defined location for s...Multiplayer Quiz: Release 1_6_351_0: A beta release of the next version. Please leave any errors in discussions or comments.Native code wrapping using c# : fsutil sparse commands: Fsutil sparse file native code - c sharp wrapper: Project Description A C# code wrapping a native code-Sparse files1 The code is about SPARSE files- the abillity to create huge files (for future us...Nice Libraries: 1.30 build 50325.01: Release 1.30 build 50325.01Pretty Good Frontend: Pretty Good Frontend binaries v1.0: This is the first public release of the Pretty Good Frontend binariesPylor: Pylor 0.1 alpha: This is the very first published version. I hope I can put a sample project soon.Quick Performance Monitor: Version 1.1 refresh: There was a typo or two in the sample batch file. Corrected now.Rapidshare Episode Downloader: RED v0.8.3: 0.8.1 introduced the ability to advance to the next episode. In 0.8.2 a bug was found that if episode number is less then 10, then the preceding 0...RapidWebDev - .NET Enterprise Software Development Infrastructure: RapidWebDev 1.52: RapidWebDev is an infrastructure helps to develop enterprise software solutions in Microsoft .NET easily and productively. This is the release vers...thommo cannon: game: gamethommo cannon: setup: setupthommo cannon: test: testTinare: Tinare DLL: Tinare DLL is a dynamic-link library written in C# which provides the functions to encrypt and decrypt a byte stream with tinare.WeatherBar: WeatherBar 2.1 [No Installation]: Minor changes to release 2.0 (http://weatherbar.codeplex.com/releases/view/42490). Fixed the bug that caused an exception to be thrown if the user...Most Popular ProjectsMetaSharpRawrWBFS ManagerASP.NET Ajax LibrarySilverlight ToolkitMicrosoft SQL Server Product Samples: DatabaseAJAX Control ToolkitLiveUpload to FacebookWindows Presentation Foundation (WPF)ASP.NETMost Active ProjectsRawrjQuery Library for SharePoint Web ServicesBlogEngine.NETMicrosoft Biology FoundationFarseer Physics Enginepatterns & practices: Composite WPF and SilverlightLINQ to TwitterTable2ClassFluent Ribbon Control SuiteNB_Store - Free DotNetNuke Ecommerce Catalog Module

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• How to implement a 2d collision detection for Android

  - by Michael Seun Araromi

  I am making a 2d space shooter using opengl ES. Can someone please show me how to implement a collision detection between the enemy ship and player ship. The code for the two classes are below: Player Ship Class: package com.proandroidgames; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import javax.microedition.khronos.opengles.GL10; public class SSGoodGuy { public boolean isDestroyed = false; private int damage = 0; private FloatBuffer vertexBuffer; private FloatBuffer textureBuffer; private ByteBuffer indexBuffer; private float vertices[] = { 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, }; private float texture[] = { 0.0f, 0.0f, 0.25f, 0.0f, 0.25f, 0.25f, 0.0f, 0.25f, }; private byte indices[] = { 0, 1, 2, 0, 2, 3, }; public void applyDamage(){ damage++; if (damage == SSEngine.PLAYER_SHIELDS){ isDestroyed = true; } } public SSGoodGuy() { ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); byteBuf.order(ByteOrder.nativeOrder()); vertexBuffer = byteBuf.asFloatBuffer(); vertexBuffer.put(vertices); vertexBuffer.position(0); byteBuf = ByteBuffer.allocateDirect(texture.length * 4); byteBuf.order(ByteOrder.nativeOrder()); textureBuffer = byteBuf.asFloatBuffer(); textureBuffer.put(texture); textureBuffer.position(0); indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); } public void draw(GL10 gl, int[] spriteSheet) { gl.glBindTexture(GL10.GL_TEXTURE_2D, spriteSheet[0]); gl.glFrontFace(GL10.GL_CCW); gl.glEnable(GL10.GL_CULL_FACE); gl.glCullFace(GL10.GL_BACK); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glDisable(GL10.GL_CULL_FACE); } } Enemy Ship Class: package com.proandroidgames; import java.nio.ByteBuffer; import java.nio.ByteOrder; import java.nio.FloatBuffer; import java.util.Random; import javax.microedition.khronos.opengles.GL10; public class SSEnemy { public float posY = 0f; public float posX = 0f; public float posT = 0f; public float incrementXToTarget = 0f; public float incrementYToTarget = 0f; public int attackDirection = 0; public boolean isDestroyed = false; private int damage = 0; public int enemyType = 0; public boolean isLockedOn = false; public float lockOnPosX = 0f; public float lockOnPosY = 0f; private Random randomPos = new Random(); private FloatBuffer vertexBuffer; private FloatBuffer textureBuffer; private ByteBuffer indexBuffer; private float vertices[] = { 0.0f, 0.0f, 0.0f, 1.0f, 0.0f, 0.0f, 1.0f, 1.0f, 0.0f, 0.0f, 1.0f, 0.0f, }; private float texture[] = { 0.0f, 0.0f, 0.25f, 0.0f, 0.25f, 0.25f, 0.0f, 0.25f, }; private byte indices[] = { 0, 1, 2, 0, 2, 3, }; public void applyDamage() { damage++; switch (enemyType) { case SSEngine.TYPE_INTERCEPTOR: if (damage == SSEngine.INTERCEPTOR_SHIELDS) { isDestroyed = true; } break; case SSEngine.TYPE_SCOUT: if (damage == SSEngine.SCOUT_SHIELDS) { isDestroyed = true; } break; case SSEngine.TYPE_WARSHIP: if (damage == SSEngine.WARSHIP_SHIELDS) { isDestroyed = true; } break; } } public SSEnemy(int type, int direction) { enemyType = type; attackDirection = direction; posY = (randomPos.nextFloat() * 4) + 4; switch (attackDirection) { case SSEngine.ATTACK_LEFT: posX = 0; break; case SSEngine.ATTACK_RANDOM: posX = randomPos.nextFloat() * 3; break; case SSEngine.ATTACK_RIGHT: posX = 3; break; } posT = SSEngine.SCOUT_SPEED; ByteBuffer byteBuf = ByteBuffer.allocateDirect(vertices.length * 4); byteBuf.order(ByteOrder.nativeOrder()); vertexBuffer = byteBuf.asFloatBuffer(); vertexBuffer.put(vertices); vertexBuffer.position(0); byteBuf = ByteBuffer.allocateDirect(texture.length * 4); byteBuf.order(ByteOrder.nativeOrder()); textureBuffer = byteBuf.asFloatBuffer(); textureBuffer.put(texture); textureBuffer.position(0); indexBuffer = ByteBuffer.allocateDirect(indices.length); indexBuffer.put(indices); indexBuffer.position(0); } public float getNextScoutX() { if (attackDirection == SSEngine.ATTACK_LEFT) { return (float) ((SSEngine.BEZIER_X_4 * (posT * posT * posT)) + (SSEngine.BEZIER_X_3 * 3 * (posT * posT) * (1 - posT)) + (SSEngine.BEZIER_X_2 * 3 * posT * ((1 - posT) * (1 - posT))) + (SSEngine.BEZIER_X_1 * ((1 - posT) * (1 - posT) * (1 - posT)))); } else { return (float) ((SSEngine.BEZIER_X_1 * (posT * posT * posT)) + (SSEngine.BEZIER_X_2 * 3 * (posT * posT) * (1 - posT)) + (SSEngine.BEZIER_X_3 * 3 * posT * ((1 - posT) * (1 - posT))) + (SSEngine.BEZIER_X_4 * ((1 - posT) * (1 - posT) * (1 - posT)))); } } public float getNextScoutY() { return (float) ((SSEngine.BEZIER_Y_1 * (posT * posT * posT)) + (SSEngine.BEZIER_Y_2 * 3 * (posT * posT) * (1 - posT)) + (SSEngine.BEZIER_Y_3 * 3 * posT * ((1 - posT) * (1 - posT))) + (SSEngine.BEZIER_Y_4 * ((1 - posT) * (1 - posT) * (1 - posT)))); } public void draw(GL10 gl, int[] spriteSheet) { gl.glBindTexture(GL10.GL_TEXTURE_2D, spriteSheet[0]); gl.glFrontFace(GL10.GL_CCW); gl.glEnable(GL10.GL_CULL_FACE); gl.glCullFace(GL10.GL_BACK); gl.glEnableClientState(GL10.GL_VERTEX_ARRAY); gl.glEnableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glVertexPointer(3, GL10.GL_FLOAT, 0, vertexBuffer); gl.glTexCoordPointer(2, GL10.GL_FLOAT, 0, textureBuffer); gl.glDrawElements(GL10.GL_TRIANGLES, indices.length, GL10.GL_UNSIGNED_BYTE, indexBuffer); gl.glDisableClientState(GL10.GL_VERTEX_ARRAY); gl.glDisableClientState(GL10.GL_TEXTURE_COORD_ARRAY); gl.glDisable(GL10.GL_CULL_FACE); } }

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• CodePlex Daily Summary for Thursday, April 15, 2010

  CodePlex Daily Summary for Thursday, April 15, 2010New ProjectsApplication Logging Repository (ALR): The ALR is a light-weight logging framework that allows applications to log events and exceptions to a central repository.Arkane.FileProperties.DSS: Arkane.FileProperties.Dss is a library for parsing the file header of a .DSS file (as used by Olympus digital dictaphone systems) to obtain time, v...B in conTrol project: This project enables controling log-in and locking your workstation automatically, identifyng you bluetooth.DarkBook: DarkBook is a personal library project.Direct2D for Microsoft .Net: Direct2D, DirectWrite and Windows Imaging wrappers for .Net. This library allows to access Direct2D, DirectWrite and Windows Imaging Windows API f...DJ Ware: DJ Ware is an extensible music player with plugin support and innovative features to organize and explore music files. It is developed with C#, WPF...gpsMe: gpsMe is a Windows Mobile 6.x mapping solution allowing to place the user on a personnalized map. The screen requirements are VGA or WVGA but, you ...jErrorLog: jErrorLog is an error logging component for use in DotNet 2.0 or later applications. It can log error messages to any of the following: database, e...KEMET_API: Java Library (open - source). This library is a help to study egyptian hieroglyphs.Meadow: A web site project for a Swedish floorball team called Slackers. Home page built with ASP.NET 2.0, ASP.NET AJAX and SQL Server 2005.Mustang Math: Mustang Math makes it easier for young children to practice basic math facts on the computer. No keyboard or mouse required - just say the answer!...Net.Formats.oEmbed: oEmbed format implementation in c#. oEmbed is a format for allowing an embedded representation of a URL on third party sites. The simple API allows...Normlize O/R Mapper: Open source O/RM tool that participates with traditional inheritance object models as well as Hibernate/nHibernate style class shells. As I have t...N-Twill Twitter Client for VB.NET: Proyecto de cliente twitter hecho con la libreria TwitterVB2 y hecho en VB.net 2008.SIQM: Spatial Information Quality Management Toolset TIMETABLEASY Web: Under developmentTweetSharp: TweetSharp is a complete .NET library for micro-blogging platforms that allows you to write short and sweet expressions that fly to Twitter, Yammer...UISandbox: UISandbox is a sample C# source code showing how to deal with plugins requiring sandbox, when those plugins must interact with WPF application inte...WinForm SharePoint Web Part Manager: The SharePoint Web Part Manager is a WinForm tool using the SharePoint object model that enables developers and power users to add, update, delete,...WoW Character Viewer: View your World of Warcraft character (or anyone else's character), using this application. Written using Visual Basic Express 2008, then ported t...Xrns2XMod: Xrns2XMod converts from Renoise format (xrns) to mod or xm, which are more compatible formats playable from xmplay or vlc.New ReleasesArkane.FileProperties.DSS: 1.0 stable release: Executables and merge module for 1.0. (See documentation.)Bluetooth Radar: Version 2.0: Add IrDA reference for Bluetooth sending using Obex Add Project icon Add Bluetooth detection mode (Auto close application is there is no blueto...BUtil: BUtil 5.0 Alpha: Backup tasks adding.... in progressChronos WPF: Chronos v1.0 RC 1: Chronos v1.0 RC 1. Development will be feature frozen after this release, only bug fixes will be allowed. Updated nRoute assembly to v0.4 (http:...clipShow: Version 2.5: Release that addresses the canonical syntax issues in search discoverd by Tschachim (thanks again!). Also, the play list and play all menu items s...DarkBook: DarkBook alpha: Hi, here comes the alpha version of Darkbook. It has all the functions already but is still in developing. I hope it's helpful for you, at least it...DirectQ: Release 1.8.3a: Improvements to 1.8.2, which will be shortly be removed. This replaces the original 1.8.3 release from earlier today which had some late-breaking ...Effect Custom Tool for Visual Studio: Effect Custom Tool v1.1: Effect Custom Tool for Visual Studio is a visual studio 2008 extension that helps you generate c# classes from effect (*.fx) files for use with Xna...Folder Bookmarks: Folder Bookmarks 1.4.3: This is the latest version of Folder Bookmarks (1.4.3), with general improvements. It has an installer - it will create a directory 'CPascoe' in My...gpsMe: gpsMe v0.3: Required Hardware Windows Mobile 6 .Net Compact Framework 3.5 integrated gps device VGA or WVGA screen (normally works on others)IST435: Lab 4 - Enterprise Level CMS with DotNetNuke: Lab 4 - Enterprise Level CMS with DotNetNukeThis is the "starter kit" that you must base your Lab 4 on. This lab must be completed in-class.Mouse Jiggler: MouseJiggle-1.1: 1.1 release of Mouse Jiggler, now with x64 compatibility and the ability to start jiggling on run with the --jiggle or -j command-line switch.Mustang Math: MustangMath.exe: This is a quick and dirty "0.1" prototype to demonstrate the speech recognition idea. It starts asking you questions automatically on launch and k...MvcContrib: a Codeplex Foundation project: 2.0.36.0 for MVC2 (RTW): Please see the Change Log for a complete list of changes. MVC BootCamp Description of the releases: MvcContrib.Release.zip MvcContrib.dll MvcC...Nito.LINQ: Beta (v0.3): New features for this release: Several new supported platforms (see below). PDBs that are source-indexed to the appropriate CodePlex changeset. ...OpenIdPortableArea: 0.1.0.2 OpenIdPortableArea: OpenIdPortableArea.Release: DotNetOpenAuth.dll DotNetOpenAuth.xml MvcContrib.dll MvcContrib.xml OpenIdPortableArea.dll OpenIdPortableAre...PokeIn Comet Ajax Library: PokeIn Sample with Library v0.2: New version of PokeIn library with sample. v0.2 There are new features in this release and no bug detected yet.Project Tru Tiên: Elements-test V1-fix (v2): Là EL test được fix tiếp theo bản fix V1, tạm gọi đây là bản fix V2 của ELtest Trong bản fix này EL được fix thêm vụ Quest, Quest chỉnh sửa đúng t...Rule 18 - Love your clipboard: Rule 18: This is the third public beta for the first version of Rule 18. This version has been updated to support Visual Studio 2010 RTM and .NET 4.0 RTM. ...SevenZipSharp: SevenZipSharp 0.62: Added: Extraction from SFX archives. Now it is possible to unrar RAR self-extractors, unzip ZIP self-extractors, etc. Extraction from DOC, XLS, (...SharePoint Labs: SPLab3001A-FRA-Level200: SPLab3001A-FRA-Level200 This SharePoint Lab will teach the persistence object layer that SharePoint uses to centraly store configuration data and o...TTXPathNavigator: TTXPathNavigator for VS2010: Version for Visual Studio 2010turing machine simulator: SDS: SDS documentVecDraw: VecDraw_0.2.25: Alpha release for test purposesWinForm SharePoint Web Part Manager: Beta 1: First release of the WinForm SharePoitn web part manager toolXrns2XMod: Xrns2XMod 0.5.1: Mod and XM conversion format - No sample data conversion at momentZip Solution: ZipSolution 5.3: Features: 1. Added WaitMsec for visual studio support with getting access to files in post build event; 2. Added ShowTextInToolbars to app.config ...Most Popular ProjectsRawrWBFS ManagerAJAX Control ToolkitMicrosoft SQL Server Product Samples: DatabaseSilverlight ToolkitWindows Presentation Foundation (WPF)ASP.NETMicrosoft SQL Server Community & SamplesPHPExcelpatterns & practices – Enterprise LibraryMost Active ProjectsRawrpatterns & practices – Enterprise LibraryGMap.NET - Great Maps for Windows Forms & PresentationFarseer Physics EngineIonics Isapi Rewrite FilterNB_Store - Free DotNetNuke Ecommerce Catalog ModuleBlogEngine.NETjQuery Library for SharePoint Web ServicesDotRasFacebook Developer Toolkit

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• C#: Optional Parameters - Pros and Pitfalls

  - by James Michael Hare

  When Microsoft rolled out Visual Studio 2010 with C# 4, I was very excited to learn how I could apply all the new features and enhancements to help make me and my team more productive developers. Default parameters have been around forever in C++, and were intentionally omitted in Java in favor of using overloading to satisfy that need as it was though that having too many default parameters could introduce code safety issues.  To some extent I can understand that move, as I’ve been bitten by default parameter pitfalls before, but at the same time I feel like Java threw out the baby with the bathwater in that move and I’m glad to see C# now has them. This post briefly discusses the pros and pitfalls of using default parameters.  I’m avoiding saying cons, because I really don’t believe using default parameters is a negative thing, I just think there are things you must watch for and guard against to avoid abuses that can cause code safety issues. Pro: Default Parameters Can Simplify Code Let’s start out with positives.  Consider how much cleaner it is to reduce all the overloads in methods or constructors that simply exist to give the semblance of optional parameters.  For example, we could have a Message class defined which allows for all possible initializations of a Message: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message() 5: : this(string.Empty) 6: { 7: } 8:  9: public Message(string text) 10: : this(text, null) 11: { 12: } 13:  14: public Message(string text, IDictionary<string, string> properties) 15: : this(text, properties, -1) 16: { 17: } 18:  19: public Message(string text, IDictionary<string, string> properties, long timeToLive) 20: { 21: // ... 22: } 23: }   Now consider the same code with default parameters: 1: public class Message 2: { 3: // can either cascade these like this or duplicate the defaults (which can introduce risk) 4: public Message(string text = "", IDictionary<string, string> properties = null, long timeToLive = -1) 5: { 6: // ... 7: } 8: }   Much more clean and concise and no repetitive coding!  In addition, in the past if you wanted to be able to cleanly supply timeToLive and accept the default on text and properties above, you would need to either create another overload, or pass in the defaults explicitly.  With named parameters, though, we can do this easily: 1: var msg = new Message(timeToLive: 100);   Pro: Named Parameters can Improve Readability I must say one of my favorite things with the default parameters addition in C# is the named parameters.  It lets code be a lot easier to understand visually with no comments.  Think how many times you’ve run across a TimeSpan declaration with 4 arguments and wondered if they were passing in days/hours/minutes/seconds or hours/minutes/seconds/milliseconds.  A novice running through your code may wonder what it is.  Named arguments can help resolve the visual ambiguity: 1: // is this days/hours/minutes/seconds (no) or hours/minutes/seconds/milliseconds (yes) 2: var ts = new TimeSpan(1, 2, 3, 4); 3:  4: // this however is visually very explicit 5: var ts = new TimeSpan(days: 1, hours: 2, minutes: 3, seconds: 4);   Or think of the times you’ve run across something passing a Boolean literal and wondered what it was: 1: // what is false here? 2: var sub = CreateSubscriber(hostname, port, false); 3:  4: // aha! Much more visibly clear 5: var sub = CreateSubscriber(hostname, port, isBuffered: false);   Pitfall: Don't Insert new Default Parameters In Between Existing Defaults Now let’s consider a two potential pitfalls.  The first is really an abuse.  It’s not really a fault of the default parameters themselves, but a fault in the use of them.  Let’s consider that Message constructor again with defaults.  Let’s say you want to add a messagePriority to the message and you think this is more important than a timeToLive value, so you decide to put messagePriority before it in the default, this gives you: 1: public class Message 2: { 3: public Message(string text = "", IDictionary<string, string> properties = null, int priority = 5, long timeToLive = -1) 4: { 5: // ... 6: } 7: }   Oh boy have we set ourselves up for failure!  Why?  Think of all the code out there that could already be using the library that already specified the timeToLive, such as this possible call: 1: var msg = new Message(“An error occurred”, myProperties, 1000);   Before this specified a message with a TTL of 1000, now it specifies a message with a priority of 1000 and a time to live of -1 (infinite).  All of this with NO compiler errors or warnings. So the rule to take away is if you are adding new default parameters to a method that’s currently in use, make sure you add them to the end of the list or create a brand new method or overload. Pitfall: Beware of Default Parameters in Inheritance and Interface Implementation Now, the second potential pitfalls has to do with inheritance and interface implementation.  I’ll illustrate with a puzzle: 1: public interface ITag 2: { 3: void WriteTag(string tagName = "ITag"); 4: } 5:  6: public class BaseTag : ITag 7: { 8: public virtual void WriteTag(string tagName = "BaseTag") { Console.WriteLine(tagName); } 9: } 10:  11: public class SubTag : BaseTag 12: { 13: public override void WriteTag(string tagName = "SubTag") { Console.WriteLine(tagName); } 14: } 15:  16: public static class Program 17: { 18: public static void Main() 19: { 20: SubTag subTag = new SubTag(); 21: BaseTag subByBaseTag = subTag; 22: ITag subByInterfaceTag = subTag; 23:  24: // what happens here? 25: subTag.WriteTag(); 26: subByBaseTag.WriteTag(); 27: subByInterfaceTag.WriteTag(); 28: } 29: }   What happens?  Well, even though the object in each case is SubTag whose tag is “SubTag”, you will get: 1: SubTag 2: BaseTag 3: ITag   Why?  Because default parameter are resolved at compile time, not runtime!  This means that the default does not belong to the object being called, but by the reference type it’s being called through.  Since the SubTag instance is being called through an ITag reference, it will use the default specified in ITag. So the moral of the story here is to be very careful how you specify defaults in interfaces or inheritance hierarchies.  I would suggest avoiding repeating them, and instead concentrating on the layer of classes or interfaces you must likely expect your caller to be calling from. For example, if you have a messaging factory that returns an IMessage which can be either an MsmqMessage or JmsMessage, it only makes since to put the defaults at the IMessage level since chances are your user will be using the interface only. So let’s sum up.  In general, I really love default and named parameters in C# 4.0.  I think they’re a great tool to help make your code easier to read and maintain when used correctly. On the plus side, default parameters: Reduce redundant overloading for the sake of providing optional calling structures. Improve readability by being able to name an ambiguous argument. But remember to make sure you: Do not insert new default parameters in the middle of an existing set of default parameters, this may cause unpredictable behavior that may not necessarily throw a syntax error – add to end of list or create new method. Be extremely careful how you use default parameters in inheritance hierarchies and interfaces – choose the most appropriate level to add the defaults based on expected usage. Technorati Tags: C#,.NET,Software,Default Parameters

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• Authenticating clients in the new WCF Http stack

  - by cibrax

  About this time last year, I wrote a couple of posts about how to use the “Interceptors” from the REST starker kit for implementing several authentication mechanisms like “SAML”, “Basic Authentication” or “OAuth” in the WCF Web programming model. The things have changed a lot since then, and Glenn finally put on our hands a new version of the Web programming model that deserves some attention and I believe will help us a lot to build more Http oriented services in the .NET stack. What you can get today from wcf.codeplex.com is a preview with some cool features like Http Processors (which I already discussed here), a new and improved version of the HttpClient library, Dependency injection and better TDD support among others. However, the framework still does not support an standard way of doing client authentication on the services (This is something planned for the upcoming releases I believe). For that reason, moving the existing authentication interceptors to this new programming model was one of the things I did in the last few days. In order to make authentication simple and easy to extend,  I first came up with a model based on what I called “Authentication Interceptors”. An authentication interceptor maps to an existing Http authentication mechanism and implements the following interface, public interface IAuthenticationInterceptor{ string Scheme { get; } bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal);} An authentication interceptors basically needs to returns the http authentication schema that implements in the property “Scheme”, and implements the authentication mechanism in the method “DoAuthentication”. As you can see, this last method “DoAuthentication” only relies on the HttpRequestMessage and HttpResponseMessage classes, making the testing of this interceptor very simple (There is no need to do some black magic with the WCF context or messages). After this, I implemented a couple of interceptors for supporting basic authentication and brokered authentication with SAML (using WIF) in my services. The following code illustrates how the basic authentication interceptors looks like. public class BasicAuthenticationInterceptor : IAuthenticationInterceptor{ Func<UsernameAndPassword, bool> userValidation; string realm;  public BasicAuthenticationInterceptor(Func<UsernameAndPassword, bool> userValidation, string realm) { if (userValidation == null) throw new ArgumentNullException("userValidation");  if (string.IsNullOrEmpty(realm)) throw new ArgumentNullException("realm");  this.userValidation = userValidation; this.realm = realm; }  public string Scheme { get { return "Basic"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { string[] credentials = ExtractCredentials(request); if (credentials.Length == 0 || !AuthenticateUser(credentials[0], credentials[1])) { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied"); response.Headers.WwwAuthenticate.Add(new AuthenticationHeaderValue("Basic", "realm=" + this.realm));  principal = null;  return false; } else { principal = new GenericPrincipal(new GenericIdentity(credentials[0]), new string[] {});  return true; } }  private string[] ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme.StartsWith("Basic")) { string encodedUserPass = request.Headers.Authorization.Parameter.Trim();  Encoding encoding = Encoding.GetEncoding("iso-8859-1"); string userPass = encoding.GetString(Convert.FromBase64String(encodedUserPass)); int separator = userPass.IndexOf(':');  string[] credentials = new string[2]; credentials[0] = userPass.Substring(0, separator); credentials[1] = userPass.Substring(separator + 1);  return credentials; }  return new string[] { }; }  private bool AuthenticateUser(string username, string password) { var usernameAndPassword = new UsernameAndPassword { Username = username, Password = password };  if (this.userValidation(usernameAndPassword)) { return true; }  return false; }} This interceptor receives in the constructor a callback in the form of a Func delegate for authenticating the user and the “realm”, which is required as part of the implementation. The rest is a general implementation of the basic authentication mechanism using standard http request and response messages. I also implemented another interceptor for authenticating a SAML token with WIF. public class SamlAuthenticationInterceptor : IAuthenticationInterceptor{ SecurityTokenHandlerCollection handlers = null;  public SamlAuthenticationInterceptor(SecurityTokenHandlerCollection handlers) { if (handlers == null) throw new ArgumentNullException("handlers");  this.handlers = handlers; }  public string Scheme { get { return "saml"; } }  public bool DoAuthentication(HttpRequestMessage request, HttpResponseMessage response, out IPrincipal principal) { SecurityToken token = ExtractCredentials(request);  if (token != null) { ClaimsIdentityCollection claims = handlers.ValidateToken(token);  principal = new ClaimsPrincipal(claims);  return true; } else { response.StatusCode = HttpStatusCode.Unauthorized; response.Content = new StringContent("Access denied");  principal = null;  return false; } }  private SecurityToken ExtractCredentials(HttpRequestMessage request) { if (request.Headers.Authorization != null && request.Headers.Authorization.Scheme == "saml") { XmlTextReader xmlReader = new XmlTextReader(new StringReader(request.Headers.Authorization.Parameter));  var col = SecurityTokenHandlerCollection.CreateDefaultSecurityTokenHandlerCollection(); SecurityToken token = col.ReadToken(xmlReader);  return token; }  return null; }}This implementation receives a “SecurityTokenHandlerCollection” instance as part of the constructor. This class is part of WIF, and basically represents a collection of token managers to know how to handle specific xml authentication tokens (SAML is one of them). I also created a set of extension methods for injecting these interceptors as part of a service route when the service is initialized. var basicAuthentication = new BasicAuthenticationInterceptor((u) => true, "ContactManager");var samlAuthentication = new SamlAuthenticationInterceptor(serviceConfiguration.SecurityTokenHandlers); // use MEF for providing instancesvar catalog = new AssemblyCatalog(typeof(Global).Assembly);var container = new CompositionContainer(catalog);var configuration = new ContactManagerConfiguration(container); RouteTable.Routes.AddServiceRoute<ContactResource>("contact", configuration, basicAuthentication, samlAuthentication);RouteTable.Routes.AddServiceRoute<ContactsResource>("contacts", configuration, basicAuthentication, samlAuthentication); In the code above, I am injecting the basic authentication and saml authentication interceptors in the “contact” and “contacts” resource implementations that come as samples in the code preview. I will use another post to discuss more in detail how the brokered authentication with SAML model works with this new WCF Http bits. The code is available to download in this location.

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• Documenting C# Library using GhostDoc and SandCastle

  - by sreejukg

  Documentation is an essential part of any IT project, especially when you are creating reusable components that will be used by other developers (such as class libraries). Without documentation re-using a class library is almost impossible. Just think of coding .net applications without MSDN documentation (Ooops I can’t think of it). Normally developers, who know the bits and pieces of their classes, see this as a boring work to write details again to generate the documentation. Also the amount of work to make this and manage it changes made the process of manual creation of Documentation impossible or tedious. So what is the effective solution? Let me divide this into two steps 1. Generate comments for your code while you are writing the code. 2. Create documentation file using these comments. Now I am going to examine these processes. Step 1: Generate XML Comments automatically Most of the developers write comments for their code. The best thing is that the comments will be entered during the development process. Additionally comments give a good reference to the code, make your code more manageable/readable. Later these comments can be converted into documentation, along with your source code by identifying properties and methods I found an add-in for visual studio, GhostDoc that automatically generates XML documentation comments for C#. The add-in is available in Visual Studio Gallery at MSDN. You can download this from the url http://visualstudiogallery.msdn.microsoft.com/en-us/46A20578-F0D5-4B1E-B55D-F001A6345748. I downloaded the free version from the above url. The free version suits my requirement. There is a professional version (you need to pay some $ for this) available that gives you some more features. I found the free version itself suits my requirements. The installation process is straight forward. A couple of clicks will do the work for you. The best thing with GhostDoc is that it supports multiple versions of visual studio such as 2005, 2008 and 2010. After Installing GhostDoc, when you start Visual studio, the GhostDoc configuration dialog will appear. The first screen asks you to assign a hot key, pressing this hotkey will enter the comment to your code file with the necessary structure required by GhostDoc. Click Assign to go to the next step where you configure the rules for generating the documentation from the code file. Click Create to start creating the rules. Click finish button to close this wizard. Now you performed the necessary configuration required by GhostDoc. Now In Visual Studio tools menu you can find the GhostDoc that gives you some options. Now let us examine how GhostDoc generate comments for a method. I have write the below code in my code behind file. public Char GetChar(string str, int pos) { return str[pos]; } Now I need to generate the comments for this function. Select the function and enter the hot key assigned during the configuration. GhostDoc will generate the comments as follows. /// <summary> /// Gets the char. /// </summary> /// <param name="str">The STR.</param> /// <param name="pos">The pos.</param> /// <returns></returns> public Char GetChar(string str, int pos) { return str[pos]; } So this is a very handy tool that helps developers writing comments easily. You can generate the xml documentation file separately while compiling the project. This will be done by the C# compiler. You can enable the xml documentation creation option (checkbox) under Project properties -> Build tab. Now when you compile, the xml file will created under the bin folder. Step 2: Generate the documentation from the XML file Now you have generated the xml file documentation. Sandcastle is the tool from Microsoft that generates MSDN style documentation from the compiler produced XML file. The project is available in codeplex http://sandcastle.codeplex.com/. Download and install Sandcastle to your computer. Sandcastle is a command line tool that doesn’t have a rich GUI. If you want to automate the documentation generation, definitely you will be using the command line tools. Since I want to generate the documentation from the xml file generated in the previous step, I was expecting a GUI where I can see the options. There is a GUI available for Sandcastle called Sandcastle Help File Builder. See the link to the project in codeplex. http://www.codeplex.com/wikipage?ProjectName=SHFB. You need to install Sandcastle and then the Sandcastle Help file builder. From here I assume that you have installed both sandcastle and Sandcastle help file builder successfully. Once you installed the help file builder, it will be available in your all programs list. Click on the Sandcastle Help File Builder GUI, will launch application. First you need to create a project. Click on File -> New project The New project dialog will appear. Choose a folder to store your project file and give a name for your documentation project. Click the save button. Now you will see your project properties. Now from the Project explorer, right click on the Documentation Sources, Click on the Add Documentation Source link. A documentation source is a file such as an assembly or a Visual Studio solution or project from which information will be extracted to produce API documentation. From the Add Documentation source dialog, I have selected the XML file generated by my project. Once you add the xml file to the project, you will see the dll file automatically added by the help file builder. Now click on the build button. Now the application will generate the help file. The Build window gives to the result of each steps. Once the process completed successfully, you will have the following output in the build window. Now navigate to your Help Project (I have selected the folder My Documents\Documentation), inside help folder, you can find the chm file. Open the chm file will give you MSDN like documentation. Documentation is an important part of development life cycle. Sandcastle with GhostDoc make this process easier so that developers can implement the documentation in the projects with simple to use steps.

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• C#/.NET Little Wonders: The Timeout static class

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. When I started the “Little Wonders” series, I really wanted to pay homage to parts of the .NET Framework that are often small but can help in big ways.  The item I have to discuss today really is a very small item in the .NET BCL, but once again I feel it can help make the intention of code much clearer and thus is worthy of note. The Problem - Magic numbers aren’t very readable or maintainable In my first Little Wonders Post (Five Little Wonders That Make Code Better) I mention the TimeSpan factory methods which, I feel, really help the readability of constructed TimeSpan instances. Just to quickly recap that discussion, ask yourself what the TimeSpan specified in each case below is 1: // Five minutes? Five Seconds? 2: var fiveWhat1 = new TimeSpan(0, 0, 5); 3: var fiveWhat2 = new TimeSpan(0, 0, 5, 0); 4: var fiveWhat3 = new TimeSpan(0, 0, 5, 0, 0); You’d think they’d all be the same unit of time, right?  After all, most overloads tend to tack additional arguments on the end.  But this is not the case with TimeSpan, where the constructor forms are:     TimeSpan(int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds);     TimeSpan(int days, int hours, int minutes, int seconds, int milliseconds); Notice how in the 4 and 5 parameter version we suddenly have the parameter days slipping in front of hours?  This can make reading constructors like those above much harder.  Fortunately, there are TimeSpan factory methods to help make your intention crystal clear: 1: // Ah! Much clearer! 2: var fiveSeconds = TimeSpan.FromSeconds(5); These are great because they remove all ambiguity from the reader!  So in short, magic numbers in constructors and methods can be ambiguous, and anything we can do to clean up the intention of the developer will make the code much easier to read and maintain. Timeout – Readable identifiers for infinite timeout values In a similar way to TimeSpan, let’s consider specifying timeouts for some of .NET’s (or our own) many methods that allow you to specify timeout periods. For example, in the TPL Task class, there is a family of Wait() methods that can take TimeSpan or int for timeouts.  Typically, if you want to specify an infinite timeout, you’d just call the version that doesn’t take a timeout parameter at all: 1: myTask.Wait(); // infinite wait But there are versions that take the int or TimeSpan for timeout as well: 1: // Wait for 100 ms 2: myTask.Wait(100); 3:  4: // Wait for 5 seconds 5: myTask.Wait(TimeSpan.FromSeconds(5); Now, if we want to specify an infinite timeout to wait on the Task, we could pass –1 (or a TimeSpan set to –1 ms), which what the .NET BCL methods with timeouts use to represent an infinite timeout: 1: // Also infinite timeouts, but harder to read/maintain 2: myTask.Wait(-1); 3: myTask.Wait(TimeSpan.FromMilliseconds(-1)); However, these are not as readable or maintainable.  If you were writing this code, you might make the mistake of thinking 0 or int.MaxValue was an infinite timeout, and you’d be incorrect.  Also, reading the code above it isn’t as clear that –1 is infinite unless you happen to know that is the specified behavior. To make the code like this easier to read and maintain, there is a static class called Timeout in the System.Threading namespace which contains definition for infinite timeouts specified as both int and TimeSpan forms: Timeout.Infinite An integer constant with a value of –1 Timeout.InfiniteTimeSpan A static readonly TimeSpan which represents –1 ms (only available in .NET 4.5+) This makes our calls to Task.Wait() (or any other calls with timeouts) much more clear: 1: // intention to wait indefinitely is quite clear now 2: myTask.Wait(Timeout.Infinite); 3: myTask.Wait(Timeout.InfiniteTimeSpan); But wait, you may say, why would we care at all?  Why not use the version of Wait() that takes no arguments?  Good question!  When you’re directly calling the method with an infinite timeout that’s what you’d most likely do, but what if you are just passing along a timeout specified by a caller from higher up?  Or perhaps storing a timeout value from a configuration file, and want to default it to infinite? For example, perhaps you are designing a communications module and want to be able to shutdown gracefully, but if you can’t gracefully finish in a specified amount of time you want to force the connection closed.  You could create a Shutdown() method in your class, and take a TimeSpan or an int for the amount of time to wait for a clean shutdown – perhaps waiting for client to acknowledge – before terminating the connection.  So, assume we had a pub/sub system with a class to broadcast messages: 1: // Some class to broadcast messages to connected clients 2: public class Broadcaster 3: { 4: // ... 5:  6: // Shutdown connection to clients, wait for ack back from clients 7: // until all acks received or timeout, whichever happens first 8: public void Shutdown(int timeout) 9: { 10: // Kick off a task here to send shutdown request to clients and wait 11: // for the task to finish below for the specified time... 12:  13: if (!shutdownTask.Wait(timeout)) 14: { 15: // If Wait() returns false, we timed out and task 16: // did not join in time. 17: } 18: } 19: } We could even add an overload to allow us to use TimeSpan instead of int, to give our callers the flexibility to specify timeouts either way: 1: // overload to allow them to specify Timeout in TimeSpan, would 2: // just call the int version passing in the TotalMilliseconds... 3: public void Shutdown(TimeSpan timeout) 4: { 5: Shutdown(timeout.TotalMilliseconds); 6: } Notice in case of this class, we don’t assume the caller wants infinite timeouts, we choose to rely on them to tell us how long to wait.  So now, if they choose an infinite timeout, they could use the –1, which is more cryptic, or use Timeout class to make the intention clear: 1: // shutdown the broadcaster, waiting until all clients ack back 2: // without timing out. 3: myBroadcaster.Shutdown(Timeout.Infinite); We could even add a default argument using the int parameter version so that specifying no arguments to Shutdown() assumes an infinite timeout: 1: // Modified original Shutdown() method to add a default of 2: // Timeout.Infinite, works because Timeout.Infinite is a compile 3: // time constant. 4: public void Shutdown(int timeout = Timeout.Infinite) 5: { 6: // same code as before 7: } Note that you can’t default the ShutDown(TimeSpan) overload with Timeout.InfiniteTimeSpan since it is not a compile-time constant.  The only acceptable default for a TimeSpan parameter would be default(TimeSpan) which is zero milliseconds, which specified no wait, not infinite wait. Summary While Timeout.Infinite and Timeout.InfiniteTimeSpan are not earth-shattering classes in terms of functionality, they do give you very handy and readable constant values that you can use in your programs to help increase readability and maintainability when specifying infinite timeouts for various timeouts in the BCL and your own applications. Technorati Tags: C#,CSharp,.NET,Little Wonders,Timeout,Task

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• C#/.NET Little Wonders: Using &lsquo;default&rsquo; to Get Default Values

  - by James Michael Hare

  Once again, in this series of posts I look at the parts of the .NET Framework that may seem trivial, but can help improve your code by making it easier to write and maintain. The index of all my past little wonders posts can be found here. Today’s little wonder is another of those small items that can help a lot in certain situations, especially when writing generics.  In particular, it is useful in determining what the default value of a given type would be. The Problem: what’s the default value for a generic type? There comes a time when you’re writing generic code where you may want to set an item of a given generic type.  Seems simple enough, right?  We’ll let’s see! Let’s say we want to query a Dictionary<TKey, TValue> for a given key and get back the value, but if the key doesn’t exist, we’d like a default value instead of throwing an exception. So, for example, we might have a the following dictionary defined: 1: var lookup = new Dictionary<int, string> 2: { 3: { 1, "Apple" }, 4: { 2, "Orange" }, 5: { 3, "Banana" }, 6: { 4, "Pear" }, 7: { 9, "Peach" } 8: }; And using those definitions, perhaps we want to do something like this: 1: // assume a default 2: string value = "Unknown"; 3:  4: // if the item exists in dictionary, get its value 5: if (lookup.ContainsKey(5)) 6: { 7: value = lookup[5]; 8: } But that’s inefficient, because then we’re double-hashing (once for ContainsKey() and once for the indexer).  Well, to avoid the double-hashing, we could use TryGetValue() instead: 1: string value; 2:  3: // if key exists, value will be put in value, if not default it 4: if (!lookup.TryGetValue(5, out value)) 5: { 6: value = "Unknown"; 7: } But the “flow” of using of TryGetValue() can get clunky at times when you just want to assign either the value or a default to a variable.  Essentially it’s 3-ish lines (depending on formatting) for 1 assignment.  So perhaps instead we’d like to write an extension method to support a cleaner interface that will return a default if the item isn’t found: 1: public static class DictionaryExtensions 2: { 3: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 4: TKey key, TValue defaultIfNotFound) 5: { 6: TValue value; 7:  8: // value will be the result or the default for TValue 9: if (!dict.TryGetValue(key, out value)) 10: { 11: value = defaultIfNotFound; 12: } 13:  14: return value; 15: } 16: } 17:  So this creates an extension method on Dictionary<TKey, TValue> that will attempt to get a value using the given key, and will return the defaultIfNotFound as a stand-in if the key does not exist. This code compiles, fine, but what if we would like to go one step further and allow them to specify a default if not found, or accept the default for the type?  Obviously, we could overload the method to take the default or not, but that would be duplicated code and a bit heavy for just specifying a default.  It seems reasonable that we could set the not found value to be either the default for the type, or the specified value. So what if we defaulted the type to null? 1: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 2: TKey key, TValue defaultIfNotFound = null) // ... No, this won’t work, because only reference types (and Nullable<T> wrapped types due to syntactical sugar) can be assigned to null.  So what about a calling parameterless constructor? 1: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 2: TKey key, TValue defaultIfNotFound = new TValue()) // ... No, this won’t work either for several reasons.  First, we’d expect a reference type to return null, not an “empty” instance.  Secondly, not all reference types have a parameter-less constructor (string for example does not).  And finally, a constructor cannot be determined at compile-time, while default values can. The Solution: default(T) – returns the default value for type T Many of us know the default keyword for its uses in switch statements as the default case.  But it has another use as well: it can return us the default value for a given type.  And since it generates the same defaults that default field initialization uses, it can be determined at compile-time as well. For example: 1: var x = default(int); // x is 0 2:  3: var y = default(bool); // y is false 4:  5: var z = default(string); // z is null 6:  7: var t = default(TimeSpan); // t is a TimeSpan with Ticks == 0 8:  9: var n = default(int?); // n is a Nullable<int> with HasValue == false Notice that for numeric types the default is 0, and for reference types the default is null.  In addition, for struct types, the value is a default-constructed struct – which simply means a struct where every field has their default value (hence 0 Ticks for TimeSpan, etc.). So using this, we could modify our code to this: 1: public static class DictionaryExtensions 2: { 3: public static TValue GetValueOrDefault<TKey, TValue>(this Dictionary<TKey, TValue> dict, 4: TKey key, TValue defaultIfNotFound = default(TValue)) 5: { 6: TValue value; 7:  8: // value will be the result or the default for TValue 9: if (!dict.TryGetValue(key, out value)) 10: { 11: value = defaultIfNotFound; 12: } 13:  14: return value; 15: } 16: } Now, if defaultIfNotFound is unspecified, it will use default(TValue) which will be the default value for whatever value type the dictionary holds.  So let’s consider how we could use this: 1: lookup.GetValueOrDefault(1); // returns “Apple” 2:  3: lookup.GetValueOrDefault(5); // returns null 4:  5: lookup.GetValueOrDefault(5, “Unknown”); // returns “Unknown” 6:  Again, do not confuse a parameter-less constructor with the default value for a type.  Remember that the default value for any type is the compile-time default for any instance of that type (0 for numeric, false for bool, null for reference types, and struct will all default fields for struct).  Consider the difference: 1: // both zero 2: int i1 = default(int); 3: int i2 = new int(); 4:  5: // both “zeroed” structs 6: var dt1 = default(DateTime); 7: var dt2 = new DateTime(); 8:  9: // sb1 is null, sb2 is an “empty” string builder 10: var sb1 = default(StringBuilder()); 11: var sb2 = new StringBuilder(); So in the above code, notice that the value types all resolve the same whether using default or parameter-less construction.  This is because a value type is never null (even Nullable<T> wrapped types are never “null” in a reference sense), they will just by default contain fields with all default values. However, for reference types, the default is null and not a constructed instance.  Also it should be noted that not all classes have parameter-less constructors (string, for instance, doesn’t have one – and doesn’t need one). Summary Whenever you need to get the default value for a type, especially a generic type, consider using the default keyword.  This handy word will give you the default value for the given type at compile-time, which can then be used for initialization, optional parameters, etc. Technorati Tags: C#,CSharp,.NET,Little Wonders,default

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