title: SolutionDir set to *Undefined* in post-build xcopy event
body: <p>I have a project that has a post-build event that xcopies a DLLs to a certain directory:</p>
  
  <pre><code>xcopy "$(TargetDir)$(TargetName).dll" "$(SolutionDir)..\UdpLocationService\bin\Plugins\" /d /y
  xcopy "$(TargetDir)$(TargetName).pdb" "$(SolutionDir)..\UdpLocationService\bin\Plugins\" /d /y
  </code></pre>
  
  <p>However, I have CruiseControl.NET set up as a build server and MSBuild is failing on building that project due to this xcopy post-build event:</p>
  
  <pre><code>MSB3073: The command "xcopy "C:\Build\Services\Windows\VehicleServer\Plugins\Payload\bin\Debug\Payload.dll" "*Undefined*..\UdpLocationService\bin\Plugins\" /d /y xcopy "C:\Build\Services\Windows\VehicleServer\Plugins\Payload\bin\Debug\Payload.pdb" "*Undefined*..\UdpLocationService\bin\Plugins\" /d /y" exited with code 4. in Microsoft.Common.targets(3397, 13)
  </code></pre>
  
  <p>Any suggestions to get this fixed?</p>