C # exe program two separate direct communication

The sender

//WM_COPYDATA消息所要求的数据结构 public struct CopyDataStruct {     public IntPtr dwData;     public int cbData;       [MarshalAs(UnmanagedType.LPStr)]       public string lpData; }   public const int WM_COPYDATA = 0x004A;   //通过窗口的标题来查找窗口的句柄 [DllImport("User32.dll", EntryPoint = "FindWindow")] private static extern int FindWindow(string lpClassName, string lpWindowName);   //在DLL库中的发送消息函数 [DllImport("User32.dll", EntryPoint = "SendMessage")] private static extern int SendMessage     (     int hWnd,                         // 目标窗口的句柄      int Msg,                          // 在这里是WM_COPYDATA     int wParam,                       // 第一个消息参数     ref  CopyDataStruct lParam        // 第二个消息参数    );   private void button1_Click(object sender, EventArgs e) {     //将文本框中的值， 发送给接收端               string strURL = txtImpinj.Text;     CopyDataStruct cds;     cds.dwData = (IntPtr)1; //这里可以传入一些自定义的数据，但只能是4字节整数          cds.lpData = strURL;    //消息字符串     cds.cbData = System.Text.Encoding.Default.GetBytes(strURL).Length + 1;  //注意，这里的长度是按字节来算的     SendMessage(FindWindow(null, "接收端"), WM_COPYDATA, 0, ref cds);       // 这里要修改成接收窗口的标题“接收端”     //this.Close(); }

Receiving end

//WM_COPYDATA消息所要求的数据结构 public struct CopyDataStruct {     public IntPtr dwData;     public int cbData;       [MarshalAs(UnmanagedType.LPStr)]     public string lpData; }   private const int WM_COPYDATA = 0x004A; //接收消息方法 protected override void WndProc(ref System.Windows.Forms.Message e) {     if (e.Msg == WM_COPYDATA)     {         CopyDataStruct cds = (CopyDataStruct)e.GetLParam(typeof(CopyDataStruct));         textBox1.Text = cds.lpData.ToString();  //将文本信息显示到文本框         //MessageBox.Show(cds.lpData);     }     base.WndProc(ref e); }