PlatformTarget

PlatformTarget is a property used in .NET project files to specify the processor architecture for the compiled output. It is an MSBuild setting that can be set to x86, x64, or AnyCPU, and it guides how the assembly is generated and how it will run on different operating systems.

The meaning of the values is as follows: x86 produces a 32-bit assembly that runs only on 32-bit Windows or under WOW64 on 64-bit Windows. x64 produces a 64-bit assembly that runs on 64-bit Windows. AnyCPU produces a platform-agnostic assembly that can run as 32-bit on 32-bit OS and as 64-bit on 64-bit OS; on 64-bit Windows the runtime may apply a Prefer 32-bit setting that can influence whether an AnyCPU application runs as 32-bit or 64-bit. In practice, this setting matters most when the project consumes native or unmanaged libraries with specific bitness requirements.

PlatformTarget interacts with dependencies and native code. If the project references unmanaged DLLs or uses P/Invoke, the bitness of those libraries must be compatible with the produced PlatformTarget. Mismatches can cause load-time or runtime failures. For mixed-mode assemblies or certain C++/CLI projects, selecting the correct target architecture is essential.

Setting PlatformTarget can be done in Visual Studio through the project properties (Build > Platform target) or by editing the project file to include a tag such as <PlatformTarget>x86</PlatformTarget> (with x86, x64, or AnyCPU as the value). In SDK-style projects, PlatformTarget may be optional or inferred, but it remains a relevant control for compatibility with native dependencies and deployment considerations.

Notes: In modern .NET Core and .NET 5+/cross-platform scenarios, platform targeting affects deployment and native bindings more than runtime behavior, where runtime identifiers and self-contained deployments may be more influential.