DLL函数未导出：无法找到名为TestFunc的入口点

I'm busy getting to know a tiny bit of C/C++, and interop with C#. I've checked several examples of creating a simple Win32 DLL and using this from C#, but when I try and call into my DLL, I get the runtime error: "Unable to find an entry point named TestFunc". My DLL looks like this, and I created it from a Win32 DLL project, with the empty project option:I'm busy getting to know a tiny bit of C/C++, a