Conditionally use 32/64 bit reference when building in Visual Studio

Question

I have a project that builds in 32/64-bit and has corresponding 32/64-bit dependencies. I want to be able to switch configurations and have the correct reference used, but I don't know how to tell Visual Studio to use the architecture-appropriate dependency.

Maybe I'm going about this the wrong way, but I want to be able to switch between x86 and x64 in the configuration dropdown, and have the referenced DLL be the right bitness.

Answer 1

Hi,

Could you reference both DLL and use IoC container to setup a profile to use the desired dll depending on build type?

Regards

Iain

Answer 2

AFAIK, if your project requires references that are 32-bit or 64-bit specific (i.e. COM-interop assemblies), and you have no interest in manually editing the .csproj file, then you'll have to create separate 32-bit and 64-bit projects.

I should note that the following solution is untested, but should work. If you are willing to manually edit the .csproj file, then you should be able to achieve the desired result with a single project. The .csproj file is just an MSBuild script, so for a full reference, look here. Once you open the .csproj file in an editor, locate the <Reference> elements. You should be able to split these elements out in to 3 distinct item groups: references that aren't platform specific, x86-specific references, and x64-specific references.

Here is an example that assumes your project is configured with target platforms named "x86" and "x64"

<!-- this group contains references that are not platform specific -->
<ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Core" />
    <!-- any other references that aren't platform specific -->
</ItemGroup>

<!-- x86 specific referneces -->
<ItemGroup Condition=" '$(Platform)' == 'x86' ">
    <Reference Include="MyComAssembly.Interop">
        <HintPath>..\..\lib\x86\MyComAssembly.Interop.dll</HintPath>
    </Reference>

    <!-- any additional x86 specific references -->
</ItemGroup>

<!-- x64 specific referneces -->
<ItemGroup Condition=" '$(Platform)' == 'x64' ">
    <Reference Include="MyComAssembly.Interop">
        <HintPath>..\..\lib\x64\MyComAssembly.Interop.dll</HintPath>
    </Reference>

    <!-- any additional x64 specific references -->
</ItemGroup>

Now, when you set your project/solution build configuration to target the x86 or x64 platform, it should include the proper references in each case. Of course, you'll need to play around with the <Reference> elements. You could even setup dummy projects where you add the x86 and x64 references, and then just copy the necessary <Reference> elements from those dummy project files to your "real" project file.

Edit 1
Here's a link to the common MSBuild project items, which I accidentally left out from the original post: http://msdn.microsoft.com/en-us/library/bb629388.aspx