MSBuild to copy output of a dependency project into another folder

I have a project that have a couple project dependencies, I want to throw the output (dll) of the two dependent project into another folder, but it doesn't seem to work. The following is something what I have, is there anything wrong?

<ItemGroup>
  <ProjectReference Include="..\..\a\a.csproj">
    <Project>{xxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}<开发者_StackOverflow;/Project>
    <Name>Client</Name>
  </ProjectReference>
  <ProjectReference Include="..\..\b\b.csproj">
    <Project>{yyyyyy-yyyy-yyyy-yyyy-yyyyyyyyyyyy}</Project>
    <Name>Server</Name>
  </ProjectReference>
</ItemGroup>
<Target Name="BuildOtherProjects">
  <MSBuild Projects="@(ProjectReference)" Targets="Build">
    <Output TaskParameter="TargetOutputs" ItemName="DependentAssemblies" />
  </MSBuild>
  <Copy SourceFiles="@(DependentAssemblies)"   DestinationFolder="$(OtherBuildLocation)\Build\Output" SkipUnchangedFiles="true" />
</Target>

Firstly, at what point is it failing? Try debugging what you've got with a few message tasks set to importance="high" (to ensure their visibility in the output). The first check that springs to mind, is what's actually in the DependentAssemblies ItemGroup after the MSBuild task?

If you're doing what I think you're trying to do though, that is, get all dependencies into a single directory, perhaps for deployment, then have you considered instead having all projects output to the same directory? OutDir and OutputPath are two properties you can make use of.