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.

  
    $([System.Environment]::GetFolderPath(System.Environment.SpecialFolder.MyDocuments))
  

  
    
  

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.

  
    $([System.Environment]::GetFolderPath(SpecialFolder.MyDocuments))
  

  
    
  

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

• Property Functions Part 1
• Property Functions MSDN Reference
• Property Functions: MSBuild Team Blog

Sayed Ibrahim Hashimi – @sayedihashimi