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

Here is what I've done in a previous project, which will require the manual edition of the .csproj file(s). You also need separate directories for the different binaries, ideally siblings of each other, and with the same name as the platform you are targeting.

After adding a single platform's references to the project, open the .csproj in a text editor. Before the first <ItemGroup> element within the <Project> element, add the following code, which will help determine which platform you're running (and building) on.

<!-- Properties group for Determining 64bit Architecture -->
<PropertyGroup>
  <CurrentPlatform>x86</CurrentPlatform>
  <CurrentPlatform Condition="'$(PROCESSOR_ARCHITECTURE)'=='AMD64' or '$(PROCESSOR_ARCHITEW6432)'=='AMD64'">AMD64</CurrentPlatform>
</PropertyGroup>

Then, for your platform specific references, you make changes such as the following:

<ItemGroup>
  <Reference Include="Leadtools, Version=16.5.0.0, Culture=neutral, PublicKeyToken=9cf889f53ea9b907, processorArchitecture=x86">
    <SpecificVersion>False</SpecificVersion>
    <HintPath>..\..\Lib\Leadtools\$(CurrentPlatform)\Leadtools.dll</HintPath>
  </Reference>
  <Reference Include="Leadtools.Codecs, Version=16.5.0.0, Culture=neutral, PublicKeyToken=9cf889f53ea9b907, processorArchitecture=x86">
    <SpecificVersion>False</SpecificVersion>
    <HintPath>..\..\Lib\Leadtools\$(CurrentPlatform)\Leadtools.Codecs.dll</HintPath>
  </Reference>
  <Reference Include="Leadtools.ImageProcessing.Core, Version=16.5.0.0, Culture=neutral, PublicKeyToken=9cf889f53ea9b907, processorArchitecture=x86">
    <SpecificVersion>False</SpecificVersion>
    <HintPath>..\..\Lib\Leadtools\$(CurrentPlatform)\Leadtools.ImageProcessing.Core.dll</HintPath>
  </Reference>
  <Reference Include="System" />
  <Reference Include="System.Core" />
  <Reference Include="System.Data.Entity" />
  <!--  Other project references -->
</ItemGroup>

Note the use of the $(CurrentPlatform) property, which we defined above. You could, instead, use conditionals for which assemblies to include for which platform. You could also need to:

• Replace the $(PROCESSOR_ARCHITEW6432) and $(PROCESSOR_ARCHITECTURE) with $(Platform) to consider ONLY the target platform of the projects
• Alter the platform determination logic in order to be appropriate to the current machine, so that you're not building/referencing a 64 bit binary to execute on a 32 bit platform.

I had this written up originally for an internal Wiki at work, however, I've modified it and posted the full process to my blog, if you are interested in the detailed step-by-step instructions.