c# 進程間通訊 COPYDATA

發送端：

static void Main(string[] args)
        {
            while(true)
            {
                String strInput = Console.ReadLine();
                if (strInput == "q")
                    break;

                int hPdf = IPCTool.FindWindow(null, @"pdfWatermark0");
                if (hPdf != 0)
                {
                    IPCTool.COPYDATASTRUCT cds;
                    cds.dwData = (IntPtr)256;
                    cds.lpData = "hello cSharpTestConsole";
                    cds.cbData = 256;

                    IPCTool.SendMessage(hPdf, 0x004A, 0, ref cds);
                }
            }
        }

接收端：

// override window proc
        protected override void DefWndProc(ref Message m)
        {
            switch(m.Msg)
            {
                case 0x004A:
                    {
                        IPCTool.COPYDATASTRUCT cdata = new IPCTool.COPYDATASTRUCT();
                        
                      //cdata = (IPCTool.COPYDATASTRUCT)Marshal.PtrToStructure(m.LParam, typeof(IPCTool.COPYDATASTRUCT));

                        cdata = (IPCTool.COPYDATASTRUCT)m.GetLParam(cdata.GetType());

                    //  MessageBox.Show(cdata.lpData);
                        break;
                    }
                default:
                    base.DefWndProc(ref m);
                    break;
            }
        }

結構定義：

public class IPCTool
    {
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }

        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        public static extern int SendMessage(
         int hWnd, //目標視窗的handle
         int Msg, // 訊息
         int wParam, // 第一個訊息參數
         ref COPYDATASTRUCT lParam // 第二個訊息參數
         );

        [DllImport("User32.dll", EntryPoint = "FindWindow")]
        public static extern int FindWindow(string lpClassName, string
         lpWindowName);

        const int WM_COPYDATA = 0x004A;
    }