How to conditionally include MASM .asm files depending on platform/configuration (32/64-bit)

Question

I'm using Visual Studio 2010. I have two different MASM assembly files, one for 32-bit builds and one for 64-bit. The relevant part of my .vcxproj looks like this:

  <ItemGroup>
    <MASM Include="asmcode32.asm" Condition="'$(Platform)'=='Win32'" />
    <MASM Include="asmcode64.asm" Condition="'$(Platform)'=='x64'" />
  </ItemGroup>

My problem is this: The only file shown in Solution Explorer is the one for whichever configuration (Win32 / x64) is selected when Visual Studio is opened. Even unloading and reloading the project is insufficient - I must close and re-open visual studio for the other file to be shown.

I would prefer that both files be shown all the time, regardless of which configuration is selected. I could live with the visible item changing, depending on which solution is selected.

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Example:

Visual Studio is opened with the x64 configuration selected. Only asmcode64.asm is shown:

When I change to the Win32 configuration (via the "Solution Platforms" drop-down), asmcode32.asm is still not visible. Again, even unload + reload does not make it visible.

With Win32 still selected, I can close Visual Studio and re-open it. Only now is asmcode32.asm visible:

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Is there something else I can do with my .vcxproj file to show both files?

Perhaps adding the Condition= to the <MASM items was not the correct solution. If this is indeed the case, how can I configure the project to compile as I intend it?

This only applies to MASM .asm files. The equivalent operation for C/C++ files is to use the "Excluded From Build" option in the file's properties (this option doesn't exist for MASM files):

Answer 1

You're¹ doing it wrong.

The Conditional= solution works, but using it causes the behavior you're¹ seeing. Visual Studio appears to only evaluate which files will be shown in the Solution Explorer once. Basically this makes Visual Studio think that the file isn't even a part of the project.

The real solution is to use the same <ExcludedFromBuild> tags that the C files use (which are added when you select the "Excluded From Build" option in the file's properties pages.

  <ItemGroup>
    <!-- This causes the items to not be shown in Solution Explorer -->
    <!--
    <MASM Include="asmcode32.asm" Condition="'$(Platform)'=='Win32'" />
    <MASM Include="asmcode64.asm" Condition="'$(Platform)'=='x64'" />
    -->

    <!-- This is the right solution. -->
    <MASM Include="asmcode32.asm">
      <ExcludedFromBuild Condition="'$(Platform)'=='x64'">true</ExcludedFromBuild>
    </MASM>
    <MASM Include="asmcode64.asm">
      <ExcludedFromBuild Condition="'$(Platform)'=='Win32'">true</ExcludedFromBuild>
    </MASM>
  </ItemGroup>

It's a shame that this option is not exposed via the GUI, like it is for C files.

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