问题
I have three projects, ProjectA (exe), ProjectB (exe) and ProjectD (class library)
Project A references the System.Data.OracleClient.dll and ProjectD. Project B just references ProjectD. The 32-bit client version of oracle is installed and therefore ProjectA has to be a 32-bit application. Project B can be built as a 64-bit application.
Project A build settings:
Platform: Active (x86)
Platform target: x86
Project B build settings:
Platform: Active (Any CPU)
Platform target: Any CPU
My questions are what should the build settings be for ProjectD (the class library) and when ProjectA and ProjectB get built does it build ProjectD differently? A deeper explanation of the CLR would be great in terms of communications of the projects.
ProjectA and ProjectB are to be used on 64-bit Windows Server 2008. No installation, just standalone exe's.
回答1:
Only the Platform target setting for the EXE project matters. That's the assembly that gets loaded first and determines the bitness of the entire process.
A DLL doesn't get a choice, it must be compatible with whatever was selected by the EXE project. Picking AnyCPU for a DLL project is therefore almost always the correct selection.
There are just a few cases where you'd use an explicit setting. You'd only do so if you know that the class library has a dependency on some kind of native code, like the Oracle provider, and that trying to run that native code in the wrong bitness produces a completely inscrutable exception. You can avoid that exception and get a (slightly) better one by picking the Platform target for the DLL, the program will fail with a BadImageFormatException early when it tries to load the assembly. Albeit that this exception isn't exactly a very informative one either. Some odds that an admin is going to try to reinstall the DLL a couple of times before deciding that the real problem is elsewhere.
So basic ground rules: pick x86 for the EXE project, AnyCPU for all other class library projects, a nastygram to Oracle for doing nothing to make this easy.
回答2:
My questions are what should the build settings be for ProjectD (the class library) and when ProjectA and ProjectB get built does it build ProjectD differently? A deeper explanation of the CLR would be great in terms of communications of the projects.
Just use Any CPU for your lib. It'll build a unique assembly that can be executed in both 32-bit en 64-bit environments.
Technically, the just in time compilation with either produce 32-bit code or 64-bit code at runtime.
来源：https://stackoverflow.com/questions/15499553/how-to-build-x64-and-x86-projects-that-reference-same-projects