PostMessage()给winform窗口发送信息

背景：在解决方案中，c++实现了一个通信DLL，通信某些的状态需要转发给上层的winform窗口，在界面通过图标显示状态.
解决方案：通过发送自定义windows消息，重写winform窗口处理消息的函数。
解决流程：
1.在DLL的头文件中自定义windows消息

#define IGNITIONON_MSG  WM_USER + 1
#define IGNITIONOFF_MSG  WM_USER + 2
#define VCICONNECT_MSG WM_USER+3
#define  VCIDISCONNECT_MSG WM_USER+4

2.在winform代码文件中定义消息
public const int USER = 0x0400;//用户自定义消息的开始数值
public const int IGNITIONON_MSG = USER+1;
public const int IGNITIONOFF_MSG = USER + 2;
public const int VCICONNECT_MSG = USER + 3;
public const int VCIDISCONNECT_MSG = USER + 4;
3.向dll中传递winform句柄
BlueTooth blue = BlueTooth.GetInstance(strVciName,this.Handle);

static BlueTooth^ GetInstance(String^ strVciName,IntPtr Hwnd)
        {

            bool status=false;
            if (nullptr == Blue)
            {
                Blue = gcnew BlueTooth();
                status=Blue->InitEngin(strVciName);
            }
            else
            {
                status = Blue->InitEngin(strVciName);
            }
            if (status)
            {
                Blue->m_Impl->SetWindow(Hwnd.ToInt32());
                return Blue;
            }
            else
            {
                return nullptr;
            }

        }

4.发送消息
PostMessage((HWND)pBlueTooth->m_Wnd, VCICONNECT_MSG, 0, 0);
5.重写winform窗口消息处理函数

  protected override void DefWndProc(ref System.Windows.Forms.Message m)
        {

            switch (m.Msg)
            {
                case IGNITIONON_MSG:
                    {                       
                    }
                    break;
                case IGNITIONOFF_MSG:
                    {
                    }
                    break;
                case VCICONNECT_MSG:
                    {
                    }
                    break;
                case VCIDISCONNECT_MSG:
                    {
                   }
                    break;
                default:
                    base.DefWndProc(ref m);
                    break;
            }
        }