用WM_COPYDATA传递struct

    利用WM_COPYDATA可以轻松实现两个进程间的通信，但是一般都是传string数据，今天看到CSDN上有人问如何传Struct。下面是我的解决方法。

[StructLayout(LayoutKind.Sequential)]
            public struct COPYDATASTRUCT
        {
            public int dwData;
            public int cbData;
            public int lpData;
        }
        [DllImport("user32", EntryPoint = "SendMessageA")]
        public static extern int SendMessage(int Hwnd, int wMsg, int wParam, ref COPYDATASTRUCT lParam);
        const int WM_COPYDATA = 0x004A;

        //定义要传递的Struct
        [StructLayout(LayoutKind.Sequential)]
        struct WholeInfo
        {
            //SizeConst指定字符串很重要，后面要用到
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10)]
            public string cPath;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10)]
            public string lPath;
            public bool status;
        }


//发送方代码

            WholeInfo h=new WholeInfo();
            h.lPath="lPath";
            h.cPath ="cPath";
            h.status=true;
            int size = Marshal.SizeOf(typeof(WholeInfo ));
            byte[] Bytes = new byte[size];
            //根据定义的尺寸分配内存块
            GCHandle GC = GCHandle.Alloc(Bytes, GCHandleType.Pinned);
            IntPtr ptr1 = GC.AddrOfPinnedObject();
            //获得Struct对应的IntPtr
            Marshal.StructureToPtr(h, ptr1,false );            
            SendData.lpData = ptr1.ToInt32();
            SendData.cbData =size;           

            int intHWnd  = FindWindow(null,@"接收方");
            if (intHWnd > 0)
            {
                SendMessage(intHWnd ,  WM_COPYDATA, 0,ref (SendData));
            }

//接收方代码

        //处理消息
        protected override void DefWndProc(ref System.Windows.Forms.Message m)
        {
            switch(m.Msg)
            {
                case WM_COPYDATA:
                    COPYDATASTRUCT RecvData = (COPYDATASTRUCT)m.GetLParam(typeof(COPYDATASTRUCT));
                     WholeInfo h = (WholeInfo)Marshal.PtrToStructure((IntPtr)RecvData.lpData, typeof(WholeInfo));
                    this.textBox1.Text = h.cPath ;
                    
                    break;
                default:
                    base.DefWndProc(ref m);
                    break;

            }

        }

关键的代码就是
[MarshalAs(UnmanagedType.ByValTStr, SizeConst = 10)]

这样C#才能分配正确的内存位置，但是要记住一个汉字占2位