msbuild - How to add content from a target in a csproj file?

Question

I would like to add content to my web application depending on the configuration. I have declared the target in the initials target and the target looks like this :

  <Target Name="ApplicationNameDefinition" Outputs="$(MashupName)">
<MSBuild.ExtensionPack.Framework.TextString TaskAction="StartsWith" String1="$(ConfigurationName)" String2="Config1">
  <Output TaskParameter="Result" PropertyName="isConfig1" />
</MSBuild.ExtensionPack.Framework.TextString>
<MSBuild.ExtensionPack.Framework.TextString TaskAction="StartsWith" String1="$(ConfigurationName)" String2="Config2">
  <Output TaskParameter="Result" PropertyName="isConfig2" />
</MSBuild.ExtensionPack.Framework.TextString>
<MSBuild.ExtensionPack.Framework.TextString TaskAction="StartsWith" String1="$(ConfigurationName)" String2="Config3">
  <Output TaskParameter="Result" PropertyName="isConfig3" />
</MSBuild.ExtensionPack.Framework.TextString>
<MSBuild.ExtensionPack.Framework.TextString TaskAction="StartsWith" String1="$(ConfigurationName)" String2="Config4">
  <Output TaskParameter="Result" PropertyName="isConfig4" />
</MSBuild.ExtensionPack.Framework.TextString>
<Error Condition=" !$(isConfig1) And !$(isConfig2) And !$(isConfig3) And !$(isConfig4) " Text="Configuration $(ConfigurationName) Inconnue" />

<PropertyGroup>
  <MashupName Condition="$(isConfig1)">App1</MashupName>
  <MashupName Condition="$(isConfig2)">App2</MashupName>
  <MashupName Condition="$(isConfig3)">App3</MashupName>
  <MashupName Condition="$(isConfig4)">App4</MashupName>
</PropertyGroup>
<Error Condition="'$(MashupName)'==''" Text="Configuration $(MashupName) Inconnue" />
<ItemGroup >
  <Content Condition=" '$(MashupName)'!='' " Include="App_Themes\$(MashupName)\**" />
</ItemGroup>

However, the content is not added to the project. Any Idea ?

Thanks.

Answer 1

Actually this works in msbuild, but not in Visual Studio which has some cache with csproj files...