winform进程之间传递消息

两个进程FF.exe与JJ.EXE分别是发送方和接受方

发送方:

#region 向进程发送消息
        const int WM_COPYDATA = 0x004A;
        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(
            int hWnd, // handle to destination window
            int Msg, // message
            int wParam, // first message parameter
            ref COPYDATASTRUCT lParam // second message parameter
        );

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

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

        #endregion

//在需要调用的地方添加代码：
  private void button1_Click(object sender, EventArgs e)
        {

            //int WINDOW_HANDLER = FindWindow(null, @"接受方窗体的text属性");
            int WINDOW_HANDLER = FindWindow(null, @"Frmbbb");
            if (WINDOW_HANDLER != 0)
            {
                byte[] sarr = System.Text.Encoding.Default.GetBytes(this.textBox1.Text);
                int len = sarr.Length;
                COPYDATASTRUCT cds;
                cds.dwData = (IntPtr)100;
                cds.lpData = "这里是传送的消息";
                cds.cbData = len + 1;
                SendMessage(WINDOW_HANDLER, WM_COPYDATA, 0, ref cds);
            }

        }

接受方：



#region 接受方接受传来的消息
        const int WM_COPYDATA = 0x004A;
        protected override void DefWndProc(ref System.Windows.Forms.Message m)
        {
            switch (m.Msg)
            {
                case WM_COPYDATA:
                    COPYDATASTRUCT mystr = new COPYDATASTRUCT();
                    Type mytype = mystr.GetType();
                    mystr = (COPYDATASTRUCT)m.GetLParam(mytype);
                    this.textBox1.Text = mystr.lpData;//要接受消息的地方
                    break;
                default:
                    base.DefWndProc(ref m);
                    break;
            }
        }
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }
        #endregion

这样就可以完成两个进程传递消息。