进程发送消息

        #region 进程发送消息

        public const int WM_COPYDATA = 0x004A;

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

        /// <summary>
        /// 定义用户要传递的消息的数据
        /// </summary>
        [StructLayout(LayoutKind.Sequential)]
        public struct CopyDataStruct
        {
            public IntPtr dwData;
            public int cbData;        //字符串长度
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;     //字符串
        }

        [DllImport("User32.dll", EntryPoint = "SendMessage")]
        private static extern int SendMessage(
        IntPtr hWnd,                   //目标窗体句柄
        int Msg,                       //WM_COPYDATA
        int wParam,                    //自定义数值
        ref  CopyDataStruct lParam     //结构体
        );

        /// <summary>
        /// 发送消息
        /// </summary>
        /// <param name="windowName">window的title，建议加上GUID，不会重复</param>
        /// <param name="strMsg">要发送的字符串</param>
        public static void SendMessage(string windowName, string strMsg)
        {
            if (strMsg == null) return;
            IntPtr hwnd = FindWindow(null, windowName);
            //MessageBox.Show("接收消息窗口句柄:" + ((int)hwnd).ToString());
            if (hwnd != IntPtr.Zero)
            {
                CopyDataStruct cds;
                cds.dwData = IntPtr.Zero;
                cds.lpData = strMsg;
                //注意：长度为字节数
                cds.cbData = System.Text.Encoding.Default.GetBytes(strMsg).Length + 1;
                // 消息来源窗体
                int fromWindowHandler = 0;
                SendMessage(hwnd, WM_COPYDATA, fromWindowHandler, ref  cds);
            }
        }

        #endregion