Do you have a great idea for the next version of Visual Studio and you want to get your voice heard? Now is your chance! Go to twitter and post a message stating your request with the hash tag #vswish and we will take a look at it. We are listening to that channel so please do submit your feedback.

Sayed Ibrahim Hashimi

I’m happy to say that I was offered, and accepted, a position on the Web Platform and Tools team with Microsoft. I will be a Program Manager on that team. In a nutshell I will be responsible for helping to make development easier for web developers using .NET and Visual Studio. Its a very interesting role and I’m gonna be pretty challenged in the next few months to adapt to my new role. The Web Platform and Tools team has a bunch of tools that they are responsible for, and one of the is the Web Deployment Tool. I think that this will be one of the areas that I will be working in, so if you have any ideas feel free to drop me a line here or privately at sayed –DOT—hashimi [AT] gmail –DOT—com. I will start in this role in about 2 weeks.

Sayed Ibrahim Hashimi

If you are doing any kind of web development and you are not familiar with the Web Platform Installer(WPI) then you need to take a look at it. I just installed WordPress on IIS 7 with just a few clicks and  filled in a few text boxes. When you install WordPress there are some prerequisites like mySql and php. The WPI was smart enough to realize that I had neither installed, downloaded those, installed them and configured them. I was prompted for some info for those tools of course. I’ve also installed a few other apps using the WPI like, MSDeploy and dasBlog and I didn’t have any issues what so ever.

When using the WPI there are two main categories that can be installed, Web Platform and Web Applications. The Web Platform category includes items like frameworks (i.e. ASP.NET, PHP), Database (i.e. mySql) and other high level shared components. The Web Applications includes various web applications. Some others that I didn’t list previously include; DotNetNuke, nopCommerce, and umbarco just to name a few. I’m not sure how many apps are available but it looks like at least 50.

If you are an app creator and would like to share your app then you can visit the WPI Developer page for a starting point.

The past few days I was unable to Edit and Continue in Visual Studio 2010 Ultimate from my home machine, which is running Windows 7 64bit. I knew there were some issues with this on 64bit, I figured one of my projects was not targeting x86 so I just ignored it. Then today I was really getting annoyed at seeing the dialog.

So I started playing around with the configuration settings made sure that everything was in order and still no dice.

After that I performed a repair of Visual Studio, and then reset all the settings under Tools>Import and Export Settings and that still didn’t solve the problem. Then I remembered that I change my IntelliTrace settings the other day so I went to disable it and to my surprise I saw the dialog box shown below.

When I changed the IntelliTrace setting to collect call information I didn’t notice the warning stating “Edit and continue is disabled when collecting Call Information”! So I changed the setting and everything was good. Microsoft should add this to the Edit and Continue dialog box not available, I’ll ping a few people I know about that. FYI I created this question on Stackoverflow before I resolved it myself.

Sayed Ibrahim Hashimi

Recently I had the chance to work on a WPF app and it was behaving very strangely when I built and ran the application. For instance I tried to debug the application from Visual Studio and I received an error staging “Visual Studio cannot start debugging because the debug target ‘PATH HERE’ is missing. Please build the project and retry, or set the OutputPath and AssemblyName properties appropriately to point at the correct location for the target assembly.”

So I checked the properties, every thing looked good. I even built the project from the command line and it built fine. Anywayz at some point after that I was able to debug the app. But then I noticed that the UI was not getting updated with my changes. So I started digging a bit deeper. I noticed that when I ran a Clean from Visual Studio the output files for that particular project.

I then rebuilt the solution in Visual Studio. From the Output window I selected all the text,copied it, and then pasted that into an editor. After looking at the message

------ Skipped Clean: Project: R…ion: Debug Any CPU ------
Project not selected to build for this solution configuration
------ Skipped Clean: Project: R…Admin.Wpf, Configuration: Debug x86 ------
Project not selected to build for this solution configuration
------ Clean started: Project: Test…er, Configuration: Debug Any CPU ------
Build started 5/8/2010 1:10:02 AM.

I immediately knew that there was an incorrect value in the build configuration manager. You can find the configuration manager from the toolbar.

Here is what I found.

In this dialog there are two project set not to build for Debug builds; the DB project and the Wpf project. The DB project is OK to not build on Debug if there are a small % of DB changes versus code changes. If that is the case the devs can just build the DB project manually when the change it. In the case of the Wpf project, it should be set to build and the fact that it wasn’t was causing all the issues. So I checked the build check box, clicked the Close button and it was all good. You should also make sure that all other configuration as setup correctly. You don’t want to get bitten by this again.

Sayed Ibrahim Hashimi

If you are using Visual Studio 2010 then you may already be aware that Web Deployment Tool (aka MSDeploy) is integrated into Visual Studio. I’ve posted a few blog entries already about this tool. Two of the common questions that I get discussing this with people are

1. How do I exclude files from being placed in the package?
2. How do I add other files to the created package?

I will address these two questions here, first we look at the easier one, how to exclude files but we will go over a bit of background first.

Web Publishing Pipeline

With Visual Studio 2010 a new concept has been created which is known as the Web Publishing Pipeline. In a nutshell this is a process which will take your web application, build it and eventually create a package that you can use to deploy your application. This process is fully captured in MSBuild. With VS 2010 many targets and many tasks are shipped to support this process. Since its captured in MSBuild format, you can customize and extend to your hearts desire. So what we need to do is hook into this process to perform the customizations that we need. This process is captured in the following files.

%program files%\MSBuild\Microsoft\VisualStudio\v10.0\WebApplications\Microsoft.WebApplication.targets
%program files%\MSBuild\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.targets

The Microsoft.WebApplication.targets file is imported by the web applications projects file, then that file imports the Microsoft.Web.Publishing.targets file.

Excluding files from being packaged

If you open the project file of a web application created with VS 2010 towards the bottom of it you will find a line with.

<Import Project="$(MSBuildExtensionsPath32)\Microsoft\VisualStudio\v10.0\WebApplications\Microsoft.WebApplication.targets" />

BTW you can open the project file inside of VS. Right click on the project pick Unload Project. Then right click on the unloaded project and select Edit Project.

This statement will include all the targets and tasks that we need. Most of our customizations should be after that import, if you are not sure put if after! So if you have files to exclude there is an item name, ExcludeFromPackageFiles, that can be used to do so. For example let’s say that you have file named Sample.Debug.js which included in your web application but you want that file to be excluded from the created packages. You can place the snippet below after that import statement.

<ItemGroup>
  <ExcludeFromPackageFiles Include="Sample.Debug.xml">
    <FromTarget>Project</FromTarget>
  </ExcludeFromPackageFiles>
</ItemGroup>

By declaring populating this item the files will automatically be excluded. Note the usage of the FromTarget metadata here. I will not get into that here, but you should know to always specify that.

Including extra files into the package

Including extra files into the package is a bit harder but still no bigee if you are comfortable with MSBuild, and if you are not then read this.  In order to do this we need to hook into the part of the process that collects the files for packaging. The target we need to extend is called CopyAllFilesToSingleFolder. This target has a dependency property, PipelinePreDeployCopyAllFilesToOneFolderDependsOn, that we can tap into and inject our own target. So we will create a target named CustomCollectFiles and inject that into the process. We achieve this with the following (remember after the import statement).

<PropertyGroup>
  <CopyAllFilesToSingleFolderForPackageDependsOn>
    CustomCollectFiles;
    $(CopyAllFilesToSingleFolderForPackageDependsOn);
  </CopyAllFilesToSingleFolderForPackageDependsOn>
</PropertyGroup>

This will add our target to the process, now we need to define the target itself. Let’s assume that you have a folder named Extra Files that sits 1 level above your web project. You want to include all of those files. Here is the CustomCollectFiles target and we discuss after that.

<Target Name="CustomCollectFiles">
  <ItemGroup>
    <_CustomFiles Include="..\Extra Files\**\*" />

    <FilesForPackagingFromProject  Include="%(_CustomFiles.Identity)">
      <DestinationRelativePath>Extra Files\%(RecursiveDir)%(Filename)%(Extension)</DestinationRelativePath>
    </FilesForPackagingFromProject>
  </ItemGroup>
</Target>

Here what I did was create the item _CustomFiles and in the Include attribute told it to pick up all the files in that folder and any folder underneath it. Then I use this item to populate the FilesForPackagingFromProject item. This is the item that MSDeploy actually uses to add extra files. Also notice that I declared the metadata DestinationRelativePath value. This will determine the relative path that it will be placed in the package. I used the statement Extra Files%(RecursiveDir)%(Filename)%(Extension) here. What that is saying is to place it in the same relative location in the package as it is under the Extra Files folder.

Admittedly this could be easier, but its not too bad, and its pretty flexible.

Sayed Ibrahim Hashimi

/preprocess (/pp)

Since you can import other MSBuild files using the Import Element sometimes locating where a target, property or item is being defined can lead to a search that takes you through several files. It can be even more confusing if more than 1 file defines the property or target that you are interested in, because you may have thought that you found the right target but you may one that was overridden by another file. Now with MSBuild 4.0 you don’t have to search through all of those files. You can use the switch /preprocess switch. Here is the snippet from msbuild.exe /? describing it.

/preprocess[:file] 
 Creates a single, aggregated project file by inlining all the files that would be imported during a build, with their boundaries marked. This can be useful for figuring out what files are being imported and from where, and what they will contribute to the build. By default the output is written to the console window. If the path to an output file is provided that will be used instead.
 (Short form: /pp)
 Example:
   /pp:out.txt

When you use this the full logical project file is dumped to the console, or optionally to a file, and it includes references to where the elements are defined. For example I created the following very simple project files.

import-01.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <Target Name="TargetOne">
        <Message Text="From import-02.proj - TargetOne"/>
    </Target>
</Project>

import-02.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <Target Name="TargetTwo">
        <Message Text="From import-02.proj - TargetTwo"/>
    </Target>
</Project>

master.proj

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="4.0" DefaultTargets="TargetOne;TargetTwo" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

    <Target Name="TargetOne">
        <Message Text="From master.proj - TargetOne"/>
    </Target>

    <Target Name="TargetTwo">
        <Message Text="From master.proj - TargetTwo"/>
    </Target>

    <Import Project="import-01.proj"/>
    <Import Project="import-02.proj"/>
</Project>

After executing the command msbuild.exe master.proj /pp:out.xml the following was written to the out.xml file.

<?xml version="1.0" encoding="utf-8"?>
<!--
============================================================================================================================================
C:\temp\MSBuild\import\master.proj
============================================================================================================================================
-->
<Project ToolsVersion="4.0" DefaultTargets="TargetOne;TargetTwo" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <Target Name="TargetOne">
    <Message Text="From master.proj - TargetOne" />
  </Target>
  <Target Name="TargetTwo">
    <Message Text="From master.proj - TargetTwo" />
  </Target>
  <!--
============================================================================================================================================
  <Import Project="import-01.proj">

C:\temp\MSBuild\import\import-01.proj
============================================================================================================================================
-->
  <Target Name="TargetOne">
    <Message Text="From import-02.proj - TargetOne" />
  </Target>
  <!--
============================================================================================================================================
  </Import>

C:\temp\MSBuild\import\master.proj
============================================================================================================================================
-->
  <!--
============================================================================================================================================
  <Import Project="import-02.proj">

C:\temp\MSBuild\import\import-02.proj
============================================================================================================================================
-->
  <Target Name="TargetTwo">
    <Message Text="From import-02.proj - TargetTwo" />
  </Target>
  <!--
============================================================================================================================================
  </Import>

C:\temp\MSBuild\import\master.proj
============================================================================================================================================
-->
</Project>

As you can see with /pp it is very easy to see exactly what is defined where and at what location.

/detailedsummary (/ds)

Another new feature with MSBuild 4.0 is the /detailedsummary (/ds) command line switch. When you use this switch you will be shown a detailed summary (haha) of build execution. This summary includes the amount of time spent build each project file as well as the node utilization. I just preformed a build with the command msbuild RuleStack.Engine.sln /m /ds and the summary is shown below.

============================== Build Hierarchy (IDs represent configurations) =====================================================
 Id                  : Exclusive Time   Total Time   Path (Targets)
 -----------------------------------------------------------------------------------------------------------------------------------
 0                   : 0.020s           1.211s       C:\...\RuleStack.Engine.sln ()
 | 1                 : 0.667s           0.667s       C:\...\RuleStack.Engine.Common\RuleStack.Engine.Common.csproj ()
 | 3                 : 0.255s           0.718s       C:\...\Unittest\RuleStack.Engine.Tests\RuleStack.Engine.Tests.csproj ()
 | | 6               : 0.000s           0.000s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder .csproj ()
 | | 5               : 0.000s           0.000s       C:\...\RuleStack.Data\RuleStack.Data.csproj ()
 | | 1               : 0.000s           0.000s       C:\...\RuleStack.Engine.Common\RuleStack.Engine.Common.csproj ()
 | | 2               : 0.000s           0.000s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( )
 | | 8               : 0.292s           0.460s       C:\...\RuleStack.Engine.Admin.Web\RuleStack.Engine.Admin.Web.csproj ()
 | | | 24            : 0.000s           0.000s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( GetNativeManifest)
 | | | 5             : 0.000s           0.000s       C:\...\RuleStack.Data\RuleStack.Data.csproj ()
 | | . 2             : 0.000s           0.000s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( )
 | . 36              : 0.003s           0.003s       C:\...\RuleStack.Engine.Admin.Web\RuleStack.Engine.Admin.Web.csproj (GetNativeManifest)
 | 2                 : 0.319s           0.390s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( )
 | | 6               : 0.000s           0.000s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder.csproj ()
 | | 5               : 0.000s           0.000s       C:\...\RuleStack.Data\RuleStack.Data.csproj ()
 | | 17              : 0.002s           0.002s       C:\...\RuleStack.Data\RuleStack.Data.csproj (GetNativeManifest)
 | . 21              : 0.001s           0.001s       C:\...\RuleStack.Data\RuleStack.Data.csproj (GetCopyToOutputDirectoryItems)
 | 4                 : 0.382s           0.567s       C:\...\RuleStack.Services\RuleStack.Services.csproj ()
 | | 5               : 0.000s           0.000s       C:\...\RuleStack.Data\RuleStack.Data.csproj ()
 | | 2               : 0.000s           0.000s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( )
 | | 24              : 0.002s           0.002s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( GetNativeManifest)
 | . 29              : 0.001s           0.001s       C:\...\RuleStack.Engine.Backend\RuleStack.Engine.Backend.csproj ( GetCopyToOutputDirectoryItems)
 | 7                 : 0.333s           0.337s       C:\...\ObjectBinder\Test_RuleStack.ObjectBinder\Test_RuleStack.ObjectBinder.csproj ()
 | | 6               : 0.000s           0.000s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder.csproj ()
 | | 13              : 0.001s           0.001s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder.csproj (GetNativeManifest)
 | . 19              : 0.001s           0.001s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder.csproj (GetCopyToOutputDirectoryItems)
 | 6                 : 0.210s           0.210s       C:\...\ObjectBinder\RuleStack.ObjectBinder\RuleStack.ObjectBinder.csproj ()
 | 5                 : 0.277s           0.277s       C:\...\RuleStack.Data\RuleStack.Data.csproj ()
 | . 12              : 0.000s           0.000s       C:\...\RuleStack.Engine.Common\RuleStack.Engine.Common.csproj (GetNativeManifest)
 . 43                : 0.002s           0.002s       C:\...\RuleStack.Engine.Admin.Web\RuleStack.Engine.Admin.Web.csproj.metaproj ()

 ============================== Node Utilization (IDs represent configurations) ====================================================
 Timestamp:            1       2       3       4       5       6       7       8        Duration   Cumulative
 -----------------------------------------------------------------------------------------------------------------------------------
 634081842447519669:   0       x       x       x       x       x       x       x        0.018s     0.018s
 634081842447699679:   1       x       x       x       x       x       x       x        0.461s     0.479s #########
 634081842452309943:   |       6       7       5       3       4       2       x        0.130s     0.609s ##
 634081842453610018:   |       |       |       |       8       |       |       x        0.086s     0.695s #
 634081842454470067:   |       |       |       |       |       |       |       x        0.001s     0.696s
 634081842454480067:   x       |       |       |       |       |       |       x        0.001s     0.697s
 634081842454490068:   x       |       x       |       |       x       |       x        0.001s     0.698s
 634081842454500068:   x       |       x       |       |       x       x       x        0.001s     0.699s
 634081842454510069:   x       x       7       |       |       x       x       x        0.002s     0.701s
 634081842454530070:   12      x       |       |       |       x       x       x        0.002s     0.703s
 634081842454550071:   |       13      x       |       |       x       x       x        0.001s     0.704s
 634081842454560072:   |       x       7       |       |       x       x       x        0.008s     0.712s
 634081842454640076:   |       x       |       |       x       x       x       x        0.054s     0.766s #
 634081842455180107:   |       x       |       x       x       x       2       x        0.003s     0.769s
 634081842455210109:   |       x       |       17      x       x       x       x        0.002s     0.771s
 634081842455230110:   |       x       |       x       x       x       2       x        0.036s     0.807s
 634081842455590131:   |       19      x       x       x       x       |       x        0.001s     0.808s
 634081842455600131:   |       x       7       x       x       x       |       x        0.018s     0.826s
 634081842455780142:   |       x       x       x       x       x       |       x        0.036s     0.862s
 634081842456140162:   |       x       x       21      x       x       x       x        0.001s     0.863s
 634081842456150163:   |       x       x       x       x       x       2       x        0.016s     0.879s
 634081842456310172:   |       x       x       x       8       4       x       x        0.003s     0.882s
 634081842456340174:   |       x       x       x       |       x       24      x        0.001s     0.883s
 634081842456350174:   |       x       x       x       x       x       |       x        0.001s     0.884s
 634081842456360175:   |       x       x       x       8       4       x       x        0.148s     1.032s ##
 634081842457840259:   |       x       x       x       |       x       29      x        0.001s     1.033s
 634081842457850260:   |       x       x       x       |       4       x       x        0.023s     1.056s
 634081842458080273:   |       x       x       x       |       x       x       x        0.013s     1.069s
 634081842458210281:   |       x       x       x       3       x       x       x        0.004s     1.073s
 634081842458250283:   |       x       x       x       36      x       x       x        0.003s     1.076s
 634081842458280285:   |       x       x       x       3       x       x       x        0.131s     1.207s ##
 634081842459590360:   0       x       x       x       x       x       x       x        0.001s     1.208s
 634081842459600360:   43      x       x       x       x       x       x       x        0.002s     1.210s
 634081842459620361:   0       x       x       x       x       x       x       x        0.001s     1.211s
 -----------------------------------------------------------------------------------------------------------------------------------
 Utilization:          57.8    30.3    46.9    39.6    76.5    53.6    45.4    .0       Average Utilization: 43.8

In the snippet above you should know that I replace the path to the files with … to reduce the width of the output. Also the machine that I’m currently using has 8 cores so it shows 8 nodes, on your machine you may have a different number of columns for the node utilization table.

Sayed Ibrahim Hashimi

If you are using Visual Studio 2010 then you may already be familiar with the Web.config transformations that are now available. What you might not know is that you can use that same technology to transform config files outside of the build process. You will need Visual Studio 2010 installed on the machine where you perform these transformations. It is very easy to perform these transformation as well. Let’s say that we start with the app.config file shown below.

<configuration>
    <connectionStrings>
        <clear/>
        <add name="Default" connectionString="Data Source=localhost;Initial Catalog=Sample01;Integrated Security=True;" />
    </connectionStrings>
    
    <appSettings>
        <add key="contactEmail" value="contact@demo.example.com"/>
        <add key="siteUrl" value="http://demo.example.com"/>
    </appSettings>
    
</configuration>

Then we create another file, transform.xml, which contains our transformations. That file is shown below.

<configuration xmlns:xdt="http://schemas.microsoft.com/XML-Document-Transform">
    <connectionStrings>
        <clear/>
        <add name="Default" connectionString="Data Source=NOT-localhost;Initial Catalog=Sample01;Integrated Security=True;" 
             xdt:Locator="Match(name)" xdt:Transform="Replace"/>
    </connectionStrings>

    <appSettings>
        <add key="contactEmail" value="contact@example.com" xdt:Locator="Match(key)" xdt:Transform="Replace"/>
        <add key="siteUrl" value="http://example.com" xdt:Locator="Match(key)" xdt:Transform="Replace"/>
    </appSettings>

</configuration>

Then we can easily execute the transformations by using MSBuild. So I created a file named trans.proj and it is shown below.

<Project ToolsVersion="4.0" DefaultTargets="Demo" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
    <UsingTask TaskName="TransformXml"
             AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v10.0\Web\Microsoft.Web.Publishing.Tasks.dll"/>

    <Target Name="Demo">
        <TransformXml Source="app.config"
                      Transform="Transform.xml"
                      Destination="app.prod.config"/>
    </Target>
</Project>

This MSBuild file uses the TransformXml task which is shipped with Visual Studio 2010. We specify the source file, transform file and the destination. Pretty straight forward.

In order to execute this I open a Visual Studio 2010 command prompt, browse to the directory containing both files, and enter the following command

msbuild trans.proj /t:Demo

Once you do this then you will find the file app.prod.config with the following contents.

<configuration>
    <connectionStrings>
        <clear/>
        <add name="Default" connectionString="Data Source=NOT-localhost;Initial Catalog=Sample01;Integrated Security=True;"/>
    </connectionStrings>
    
    <appSettings>
        <add key="contactEmail" value="contact@example.com"/>
        <add key="siteUrl" value="http://example.com"/>
    </appSettings>
    
</configuration>

Sayed Ibrahim Hashimi

TagBuilder startTag = new TagBuilder("a");
startTag.Attributes.Add("href", string.Format("{0}/{1}", this.UrlPrefix, 1));
startTag.SetInnerText("<<");
startTag.Attributes.Add("title", "first page");
httpResponse.Write(startTag.ToString(TagRenderMode.Normal));

TagBuilder previous = new TagBuilder("a");
previous.Attributes.Add("href", string.Format("{0}/{1}", this.UrlPrefix, this.CurrentPage - 1));
previous.SetInnerText("<");
previous.Attributes.Add("title", "previous page");
httpResponse.Write(previous.ToString(TagRenderMode.Normal));

public FluentTagBuilder AddCssClass(string value)
{
    this.TagBuilder.AddCssClass(value);
    return this;
}

public FluentTagBuilder SetInnerHtml(string innerHtml)
{
    this.TagBuilder.InnerHtml = innerHtml;
    return this;
}

FluentTagBuilder startTag =
    new FluentTagBuilder("a")
    .AddAttribute("href", string.Format("{0}/{1}", this.UrlPrefix, 1))
    .SetInnerText("<<")
    .AddAttribute("title", "first page");

httpResponse.Write(startTag.ToString(TagRenderMode.Normal));

FluentTagBuilder previous =
    new FluentTagBuilder("a")
    .AddAttribute("href", string.Format("{0}/{1}", this.UrlPrefix, this.CurrentPage - 1))
    .SetInnerText("<")
    .AddAttribute("title", "previous page");

httpResponse.Write(previous.ToString(TagRenderMode.Normal));

1. FluentTagBuilder.cs
2. Pager.cs

Today a friend of mine asked me to explain (via email) a few things to another developer regarding some things I have done with the Entity Framework (EF). I figured since I already typed it up I might as well share it here as well. So here it is.

I have had 2 issues with using EF4 which I have found creative and effective work around for.

Externalizing filters

The first issue, which also exists when using other frameworks, is that you end up with an explosion of methods (and usually a lot of duplicated code). For instance let’s say you have a table to store users. This table has an ID, and Email field and, and let’s and OpenIdUrl. So you end up with the following methods.

User GetUserById(long id)

User GetUserByEmail(string email)

User GetUserByOpenIdUrl(string openIdUrl)

Usually you’ll find that each of these methods have the exact same implementation except a different where clause. Now there is a bigger problem in the fact that you cannot anticipate everything that the user may want to filter on. Because of this and the dynamic nature of IQueryable I have employed a technique using Expression Trees to allow the user to declare the exact filter to be used via a lambda expression. So for the users it’s very slick. For example I could create the following method

public User GetUser(Expression<Func<User, bool>> filter)
{
    if (filter == null)
    {
        filter = Const<User>.LinqExpression.LinqExpressionFuncAlwaysTrue;
    }

    User foundUser = null;
    using (InlineTasksContext dbContext = new InlineTasksContext())
    {
        dbContext.Connection.Open();
        foundUser = dbContext.Users.Where(filter).SingleIfExists();
    }

    return foundUser;
}

In this case I’m allowing the user to pass in a filter that is applied to the query. Here is how I could implement those three if I chose to as well.

public User GetUserById(long id)
{
    return this.GetUser(user => user.Id == id);
}
public User GetUserByEmail(string email)
{
    if (email == null) { throw new System.ArgumentNullException("email"); }

    return GetUser(user => user.Email == email);
}
public User GetUserByOpenIdUrl(string openIdUrl)
{
    if (string.IsNullOrEmpty(openIdUrl)) { throw new ArgumentNullException("openIdUrl"); }

    return GetUser(user => user.OpenIdUrl == openIdUrl);
}

Note in the first method I am using some other helpers I created. Specifically the Const<User>.LinqExpression.LinqExpressionFuncAlwaysTrue as well as the SingleIfExists

extension method. I use the AlwaysTrue expression so that way I don’t have to be worried about doing an if and having to maintain 2 select statements. And the other (SingleIfExists) is used to just return null instead of blowing up if no elements exist in the sequence.

Since they are not the purpose of this email I’ve just put them at the bottom so that you can read if you are interested.

As Keith mentioned to me a while back Expression trees are not serializable so you still end up with this problem if you are using a service based solution. But you could try and use the sample Expression Tree Serialization to take care of this for you, I’ve never tried it, but it’s on my TODO list.

.Include

My next issue is that you are forced to declare what navigation properties (i.e. table links) should be included in the query. This is done using the .Include method. So back to our GetUser example, how can a framework know what tables values should be extracted for? The end result is that the framework creator just includes a bunch of tables and 90% of the time the result is just wasted resources because the other data is never touched. Better is to provide a default which only includes the most commonly used tables and another method that allows them to specify what they want. Here is a sample for a GetTasksByUserId method

public IList<Task> GetTasksByUserId(long userId, IEnumerable<string> includeList)
{
    using (InlineTasksContext dbContext = new InlineTasksContext())
    {
        var result = (from t in dbContext.Tasks
                        .Include(includeList)
                        .Where(t=>t.User.Id == 1)
                        select t)
                        .ToList();
        return result;
    }
}
 In this example I’m using an extension method for.Include which is defined as follows.
public static ObjectQuery<T> Include<T>(this ObjectQuery<T> query, IEnumerable<string> includes)
{
    if (query == null) { throw new System.ArgumentNullException("query"); }

    if (includes != null)
    {
        foreach (string include in includes)
        {
            query.Include(include);
        }
    }
    return query;
}

So the idea is to create a framework which is both robust and easy to use, but at the same time is not overly assumptive about what the users want. I think a lot more can be done with EF and its dynamic nature.

Does that cover what you were intending Keith? Any questions/comments please send them my way.

Here are those methods I mentioned above.

public static class LinqExtensions
{
    public static T SingleIfExists<T>(this IQueryable<T> query)
    {
        if (query == null) { throw new System.ArgumentNullException("query"); }

        T result = default(T);
        if (query.Count() > 0)
        {
            result = query.Single();
        }

        return result;
    }
}
//----------------------------------------------------------------------------------------------------
public class Const<T>
{
    public static class Predicate
    {
        public static Predicate<T> AlwaysTrue
        {
            get
            {
                return x => true;
            }
        }

        public static Predicate<T> AlwaysFalse
        {
            get
            {
                return x => false;
            }
        }
    }

    public class LinqExpression
    {
        public static Expression<Func<T, bool>> LinqExpressionFuncAlwaysTrue
        {
            get
            {
                return x => true;
            }
        }
    }
}

The story around routing in ASP.NET MVC is pretty good. When a resource is requested the action that it is routed to is determined and the parameters to the action are initialized. Counter to that when you build a link you specify the argument values and it creates the url for you. So if your routes happen to change your application shouldn’t be bothered by that. One area which can be problematic for this is if you are making any ajax requests. What I’ve done to minimize the impact of route changes to Ajax requests is to have the script make a call to determine the correct route. In the most trivial case this is extremely easy. You call an action, which has a known route, passing into it the name of the action and controller. It returns to you the url for the route. This works really good, but the problem is when your routes have parameters, how do you handle those?

First let’s take a look at the Javascript and then the definition of the action method which it calls.

// wire up the event for the enter button
$("#searchText").keypress(function (event) {
    if (event.keyCode == 13) {
        // grab the text that is inside the box
        var text = $("#searchText").val();

        var routData = {
            controllerName: 'Search',
            actionName: 'Search',
            paramValues: "{ criteria: '" + text + "' }"
        };

        $.ajax({
            url: "/Home/MapRoute",
            data: routData,
            success: function (data) {
                window.location.href = data;
            },
            error: function (data) {
                alert('there was a failure on the internets');
            }
        });

    }
});

Here I am building a Javascript object named routeData. This is declared in JSON. One thing to pay attention to is the fact that the value for paramValues is a string containing JSON. This is passed to the controller action.

I’m using jQuery to make an Ajax request to /Home/MapRoute. This maps to the method shown below.

public JsonResult MapRoute(string actionName, string controllerName, string paramValues)
{
    JavaScriptSerializer jss = new JavaScriptSerializer();

    Dictionary<string, string> parameters = jss.Deserialize<Dictionary<string, string>>(paramValues);

    RouteValueDictionary rd = new RouteValueDictionary();
    foreach (string key in parameters.Keys)
    {
        rd.Add(key, parameters[key]);
    }

    UrlHelper urlHelper = new UrlHelper(this.Request.RequestContext);
    string url = urlHelper.Action(actionName, controllerName, rd);

    return Json(url, JsonRequestBehavior.AllowGet);
}

Here I’m using the JavaScriptSerializer to convert the JSON string into a dictionary, with string as key and value. I use that dictionary to create a RouteValueDictionary which is passed, along with other parameters, into the UrlHelper to generate the url. When you return the Json result you must specify JsonRequestBehavior.AllowGet, otherwise a 500 internal service error will be returned. I think this is new with ASP.NET 2.

When the action method returns, you can use that url. The drawback to this approach is that you will make an extra request to determine the url, but you will be sure that those urls are correct. Also you could cache the results with Output Caching since the routes won’t change.

Sayed Ibrahim Hashimi