C# - 다른 프로세스끼리 메시지(string) 전달하기(SendMessage)

수신

const int WM_COPYDATA = 0x4A;
 
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }
 
        protected override void WndProc(ref Message m)
        {
            try
            {
                switch (m.Msg)
                {
                    case WM_COPYDATA:
                        COPYDATASTRUCT cds = (COPYDATASTRUCT)m.GetLParam(typeof(COPYDATASTRUCT));
                        MessageBox.Show(cds.lpData);
                        break;
                    default: 
                        base.WndProc(ref m); 
                        break;
                }
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

 

송신

const int WM_COPYDATA = 0x4A;
  
        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr SendMessage(IntPtr hWnd, uint Msg, uint wParam, ref COPYDATASTRUCT lParam);
 
        public struct COPYDATASTRUCT
        {
            public IntPtr dwData;
            public int cbData;
            [MarshalAs(UnmanagedType.LPStr)]
            public string lpData;
        }
 
        private void OnButtonSendClick(object sender, EventArgs e)
        {
            string msg = this.tbMsg.Text.Trim();
 
            if (string.IsNullOrEmpty(msg))
            {
                MessageBox.Show("메세지를 입력해주세요");
                return;
            }
 
           Process []pro  =  Process.GetProcessesByName("HowToPostMessage");
           if(pro.Length > 0)
            {
                byte[] buff = System.Text.Encoding.Default.GetBytes(msg);
 
                COPYDATASTRUCT cds = new COPYDATASTRUCT();
                cds.dwData = IntPtr.Zero;
                cds.cbData = buff.Length+1;
                cds.lpData = msg;
 
                SendMessage(pro[0].MainWindowHandle, WM_COPYDATA, 0, ref cds);
            }
        }

 

 

 

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https://ehdrn.tistory.com/295

C# Process간 메세지 전송 SendMessage