c# – P / invoke函数获取指向struct 的指针

参见英文答案 > How do I handle null or optional dll struct parameters in C#1个
诸如 CreateProcess之类的函数具有指向结构的指示符.在C中,我只是将NULL作为可选参数的指针传递,而不是在堆栈上创建虚拟结构对象并将指针传递给虚拟对象.

在C#中,我已将其声明为(p / invoke)

[DllImport("kernel32.dll",CharSet = CharSet.Auto)]
        public static extern bool CreateProcess(
            string lpApplicationName,string lpCommandLine,ref SECURITY_ATTRIBUTES lpProcessAttributes,ref SECURITY_ATTRIBUTES lpThreadAttributes,bool bInheritHandles,CreateProcessFlags dwProcessCreationFlags,IntPtr lpEnvironment,string lpCurrentDirectory,ref STARTUPINFO lpStartupInfo,ref PROCESS_INFORMATION lpProcessInformation);

但是,如果我尝试为lpProcessAttributes参数或lpThreadAttributes参数传递null,则会出现编译器错误：

Error 2 Argument 3: cannot convert from ‘<null>’ to ‘ref
Debugging.Wrappers.SECURITY_ATTRIBUTES’

如何修改上面的函数签名,以便我可以为SECURITY_ATTRIBUTES参数传递null,而不会出现此编译器错误？ (如果我愿意,还能传递一个真正的结构？)

[StructLayout(LayoutKind.Sequential)]
public struct SECURITY_ATTRIBUTES {
    public int nLength;
    public IntPtr lpSecurityDescriptor;
    public int bInheritHandle;

    public static SECURITY_ATTRIBUTES Empty {
        get {
            return new SECURITY_ATTRIBUTES {
                nLength = sizeof(int)*2 + IntPtr.Size,lpSecurityDescriptor = IntPtr.Zero,bInheritHandle = 0,};
        }
    }
}