You can get it with Reflection
vb Code:
  1. Imports System.Reflection
  2.  
  3. Namespace Reflection
  4.     Public Class Peeker
  5.         Public Function GetTargetFramework(ByVal Path As String) As String
  6.             Dim asm As Assembly = Assembly.LoadFile(Path)
  7.             Return asm.ImageRuntimeVersion
  8.         End Function
  9.     End Class
  10. End Namespace