Property Functions: GetFolderPath

Today someone sent me an email asking how to call the System.Environment.GetFolderPath method passing in the value of MyDocuments for the value of the folder parameter. I was expecting the below to do the trick.

<Project ToolsVersion="4.0" 
         DefaultTargets="Demo" 
         xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <PropertyGroup>
    <Tempfile02>$([System.Environment]::GetFolderPath(System.Environment.SpecialFolder.MyDocuments))</Tempfile02>
  </PropertyGroup>

  <Target Name="Demo">
    <Message Text="TempFile01: $(TempFile02)"/>
  </Target>

</Project>

To my surprise I was faced with the following error.

Build started 3/20/2011 6:20:36 PM.

Project "C:\temp\_NET\msbuild\PropFunction01.proj" on node 1 (default targets).

C:\temp\_NET\msbuild\PropFunction01.proj(20,5): error MSB4186: Invalid static method invocation syntax: "[System.Environment]::GetFolderPath(System.Environment.Spec ialFolder.MyDocuments)". Requested value 'System.Environment.MyDocuments' was not found. Static method invocation should be of the form: $([FullTypeName]::Method()), e.g. $([System.IO.Path]::Combine(`a`, `b`)).

Done Building Project "C:\temp\_NET\msbuild\PropFunction01.proj" (default targets) -- FAILED.

Build FAILED.

So I sent an email to the MSBuild team asking “WTF why doesn’t this work?!”, and Dan Moseley (a lead dev there) sent me a snippet that worked, its below.

<Project ToolsVersion="4.0" DefaultTargets="Demo" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">

  <PropertyGroup>
    <Tempfile02>$([System.Environment]::GetFolderPath(SpecialFolder.MyDocuments))</Tempfile02>
  </PropertyGroup>

  <Target Name="Demo">
    <Message Text="TempFile01: $(TempFile02)"/>
  </Target>

</Project>

In that snippet instead of using the fully qualified class name of System.Environment.SpecialFolder.MyDocuments, for some reason you have to use the shortened name of just SpecialFolder.MyDocuments. It seems like a bug to me, but at least there is a work around!

Resources

Sayed Ibrahim Hashimi – @sayedihashimi

msbuild | MSBuild 4.0 | Visual Studio 2010 Monday, March 21, 2011 1:27:44 AM (GMT Standard Time, UTC+00:00)

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