为什么P / Invoke函数在C＃中必须是静态的？

Question

see the code:

class VirtualMemoryManager
{
    [DllImport("kernel32.dll",EntryPoint="GetCurrentProcess")]
    internal static extern IntPtr GetCurrentProcessHandle();
}

Why the "GetCurrentProcessHandle" must "static"

Answer 1

This is a requirement for P/Invoke methods because there is no consistent notion of an instance in the Windows API.

Source: http://msdn.microsoft.com/en-us/magazine/cc164123.aspx

Answer 2

Externally imported functions are static by nature. By not making them static they will not gain anything. An instance method can use local variables, which is impossible with dll import routines anyway.