Message Demo

一、 User defined message
A::窗口消息----------------
1. #define WM_MY_MSG WM_USER + 0x100
2. afx_msg LRESULT OnMyMsg(WPARAM, LPARAM);
3. LRESULT CTestDlg::OnMyMsg(WPARAM wParam, LPARAM lParam)
   {...}
4. 
BEGIN_MESSAGE_MAP(CTestDlg, CDialog)
    ...
    ON_MESSAGE(WM_MY_MSG, &CTestDlg::OnMyMsg)
END_MESSAGE_MAP()

B::线程消息----------------
1. #define  WM_MY_THRD_MSG  WM_USER + 100
2. afx_msg void OnMyThrdMsg(WPARAM, LPARAM);
3. void CTestApp::OnMyThrdMsg(WPARAM wParam, LPARAM lParam)
   {...}
4. 
BEGIN_MESSAGE_MAP(CTestApp, CWinAppEx)
    ...
    ON_THREAD_MESSAGE(WM_MY_THRD_MSG, &CTestApp::OnMyThrdMsg)
END_MESSAGE_MAP()
***How to trigger in current thread***
::PostMessage(NULL, WM_MY_THRD_MSG, 0, 0);
::PostThreadMessage(::GetCurrentThreadId(), WM_MY_THRD_MSG, 0, 0);



二、 Register Window Message 
A::窗口消息----------------
1. UINT nMsgRegistered = ::RegisterWindowMessage(TEXT("RegisterMsgName"));
2. afx_msg LRESULT OnMyRegisteredMsg(WPARAM, LPARAM);
3. LRESULT CTestDlg::OnMyRegisteredMsg(WPARAM wParam, LPARAM lParam)
   {...}
4. 
BEGIN_MESSAGE_MAP(CMyDlg, CDialog)
    ...
    ON_REGISTERED_MESSAGE(nMsgRegistered, &CTestDlg::OnMyRegisteredMsg)
END_MESSAGE_MAP()

B::线程消息----------------
1. UINT nThrdMsgRegistered = ::RegisterWindowMessage(TEXT("MyThrdMsg"));
2. afx_msg void OnMyRegisterdThrdMsg(WPARAM, LPARAM);
3. void CTestApp::OnMyRegisterdThrdMsg(WPARAM wParam, LPARAM lParam)
   {...}
4. 
BEGIN_MESSAGE_MAP(CTestApp, CWinAppEx)
    ...
    ON_REGISTERED_THREAD_MESSAGE(nThrdMsgRegistered, &CTestApp::OnMyRegisterdThrdMsg)
END_MESSAGE_MAP()
***How to trigger in current thread***
::PostMessage(NULL, nThrdMsgRegistered, 0, 0);
::PostThreadMessage(::GetCurrentThreadId(), nThrdMsgRegistered, 0, 0);



三、 PostThreadMessage
A::同一进程不同线程之间-----------------
1. 编写线程函数
UINT AFX_CDECL ThrdTest(LPVOID lpParam)
{
    MSG msg;
    while (::GetMessage(&msg, NULL, 0, 0))
    {
        switch(msg.message)
        {
        case WM_XXX:
        {...}
            break;
        ......
        default:
            break;
        }
    }

    return 0;
}
2. 启动线程
   UINT AFX_CDECL ThrdTest(LPVOID);
   AfxBeginThread(ThrdTest, ...);
3. 向线程发送消息
   ::PostThreadMessage(nThrdId, WM_XXX, wParam, lParam);
   
B::不同进程之间--------------------------
1. 进程I
#include <iostream>
#include <Windows.h>

using namespace std;

int main()
{
    MSG msg;
    while (::GetMessage(&msg, NULL, 0, 0))
    {
        switch(msg.message)
        {
        case WM_XXX:
        {...}
            break;
        ......
        default:
            break;
        }
    }

    return 0;
}

2. 进程II
CreateProcess(...);
::PostThreadMessage(nThrdId, WM_XXX, wParam, lParam);