关于WM_COMMAND消息的返回值的问题，求高人指点~~~~~~

2011-12-27 02:45:01 302 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

Windows消息投递流程：WM_COMMAND消息流程该示例通过研究基本的单文档程序的“文件”－－“打开”命令，分析WM_COMMAND消息投递流程。基于VS 2005 代码 AfxWndProc最终调用的是OnWndMsg，这个函数负责消息的分发处理。当消息是WM_COMMAND时，将消息投递给OnCommand函数。// wincore.cpp 1746 BOOL CWnd::OnWndMsg(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pRes 阅读详情

我发现调用::SendMessage发送WM_COMMAND的消息，该消息的返回值和MSDN上说的有点不同。

MSDN的说法
Return Value
If an application processes this message, it should return zero.
大致的意思就是如果应用程序处理了消息，将返回0

测试的结果
nState = ::SendMessage(this->m_hWnd, WM_COMMAND, IDC_BTN_TOGETSTAT, (LPARAM)btn_test.m_hWnd);
该条发送出去后，nState的值为1，而这个WM_COMMAND的消息是有被响应的。

求高人指点

...全文

MFC框架中WM_COMMAND消息响应顺序在MFC开发的程序中，菜单、工具条按钮等都会产生WM_COMMAND消息。而在MFC的Document/View框架中，有很多类可以响应WM_COMMAND消息，分别是框架类：CFrameWnd、CMDIChildWnd、CMDIFrameWnd；应用程序类CWinApp；文档类CDocument；以及视图类CView。当应用程序主菜单发送了一个WM_COMMAND消息时，WM_COMM 阅读详情

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不二星空 2012-02-02

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这个消息的返回值还是有点问题，发现ID值为1和0的按钮发送WM_COMMAND的消息的返回值和自己创建的按钮的返回值是不同的。。。闷。。

不二星空 2011-12-27

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[Quote=引用 12 楼 visualeleven 的回复:]
C/C++ code
AFX_STATIC BOOL AFXAPI _AfxDispatchCmdMsg(CCmdTarget* pTarget, UINT nID, int nCode,
AFX_PMSG pfn, void* pExtra, UINT nSig, AFX_CMDHANDLERINFO* pHandlerInfo)
// return TRUE to……
[/Quote]
我在研究研究。。。这个WM_COMMAND消息

不二星空 2011-12-27

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写不动代码的人 2011-12-27

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Return Values
The return value specifies the result of the message processing and depends on the message sent.

写不动代码的人 2011-12-27

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Return Values
The return value specifies the result of the message processing and depends on the message sent.

写不动代码的人 2011-12-27

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Return Values
The return value specifies the result of the message processing and depends on the message sent.

schlafenhamster 2011-12-27

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:: SendMessage
WM_COMMAND
WM_SYSCOMMAND
都说：
If an application processes this message, it should return zero.
这是SDK的范畴吧

Eleven 2011-12-27

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[Quote=引用 14 楼 ycf8788 的回复:]
引用 13 楼 zgl7903 的回复:
在对IDC_BTN_TOGETSTAT的响应中设置一个断点调试一下就明白了
MFC的加了WM_COMMAND响应时进入OnWndMsg返回1，没添加时进入DefWindowProc返回0

C/C++ code

LRESULT CWnd::WindowProc(UINT message, WPARAM wParam, LPARAM lPa……
[/Quote]
MSDN是最权威的，不表示上面说的都是正确的，因为那也是人写的~

不二星空 2011-12-27

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[Quote=引用 13 楼 zgl7903 的回复:]
在对IDC_BTN_TOGETSTAT的响应中设置一个断点调试一下就明白了
MFC的加了WM_COMMAND响应时进入OnWndMsg返回1，没添加时进入DefWindowProc返回0

C/C++ code

LRESULT CWnd::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)
{
// OnWnd……
[/Quote]

那个MSDN说的岂不是冲突。。。- -

zgl7903 2011-12-27

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在对IDC_BTN_TOGETSTAT的响应中设置一个断点调试一下就明白了
MFC的加了WM_COMMAND响应时进入OnWndMsg返回1，没添加时进入DefWindowProc返回0



LRESULT CWnd::WindowProc(UINT message, WPARAM wParam, LPARAM lParam)

{

	// OnWndMsg does most of the work, except for DefWindowProc call

	LRESULT lResult = 0;

	if (!OnWndMsg(message, wParam, lParam, &lResult))

		lResult = DefWindowProc(message, wParam, lParam);

	return lResult;

}



BOOL CWnd::OnWndMsg(UINT message, WPARAM wParam, LPARAM lParam, LRESULT* pResult)

{

	LRESULT lResult = 0;



	// special case for commands

	if (message == WM_COMMAND)

	{

		if (OnCommand(wParam, lParam))

		{

			lResult = 1;

			goto LReturnTrue;

		}

		return FALSE;

	}



LReturnTrue:

	if (pResult != NULL)

		*pResult = lResult;

	return TRUE;

}

Eleven 2011-12-27

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AFX_STATIC BOOL AFXAPI _AfxDispatchCmdMsg(CCmdTarget* pTarget, UINT nID, int nCode,

	AFX_PMSG pfn, void* pExtra, UINT nSig, AFX_CMDHANDLERINFO* pHandlerInfo)

		// return TRUE to stop routing

{

	ASSERT_VALID(pTarget);

	UNUSED(nCode);   // unused in release builds



	union MessageMapFunctions mmf;

	mmf.pfn = pfn;

	BOOL bResult = TRUE; // default is ok



	if (pHandlerInfo != NULL)

	{

		// just fill in the information, don't do it

		pHandlerInfo->pTarget = pTarget;

		pHandlerInfo->pmf = mmf.pfn;

		return TRUE;

	}



	switch (nSig)

	{

	case AfxSig_vv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND)(); // 比如处理BN_CLICKED点击事件

		break;



	case AfxSig_bv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_bCOMMAND)();

		break;



	case AfxSig_vw:

		// normal command or control notification in a range

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND_RANGE)(nID);

		break;



	case AfxSig_bw:

		// extended command (passed ID, returns bContinue)

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_COMMAND_EX)(nID);

		break;



	case AfxSig_vNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_bNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_bNOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_vwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY_RANGE)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_bwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_NOTIFY_EX)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_cmdui:

		{

			// ON_UPDATE_COMMAND_UI or ON_UPDATE_COMMAND_UI_REFLECT case

			ASSERT(CN_UPDATE_COMMAND_UI == (UINT)-1);

			ASSERT(nCode == CN_UPDATE_COMMAND_UI || nCode == 0xFFFF);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI)(pCmdUI);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	case AfxSig_cmduiw:

		{

			// ON_UPDATE_COMMAND_UI case

			ASSERT(nCode == CN_UPDATE_COMMAND_UI);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(pCmdUI->m_nID == nID);           // sanity assert

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI_RANGE)(pCmdUI, nID);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	// general extensibility hooks

	case AfxSig_vpv:

		(pTarget->*mmf.pfn_OTHER)(pExtra);

		break;

	case AfxSig_bpv:

		bResult = (pTarget->*mmf.pfn_OTHER_EX)(pExtra);

		break;



	default:    // illegal

		ASSERT(FALSE);

		return 0;

	}

	return bResult;

}

看一下这里处理COMMAND消息，最后return bResult，而bResult的默认值为TRUE。

Eleven 2011-12-27

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AFX_STATIC BOOL AFXAPI _AfxDispatchCmdMsg(CCmdTarget* pTarget, UINT nID, int nCode,

	AFX_PMSG pfn, void* pExtra, UINT nSig, AFX_CMDHANDLERINFO* pHandlerInfo)

		// return TRUE to stop routing

{

	ASSERT_VALID(pTarget);

	UNUSED(nCode);   // unused in release builds



	union MessageMapFunctions mmf;

	mmf.pfn = pfn;

	BOOL bResult = TRUE; // default is ok



	if (pHandlerInfo != NULL)

	{

		// just fill in the information, don't do it

		pHandlerInfo->pTarget = pTarget;

		pHandlerInfo->pmf = mmf.pfn;

		return TRUE;

	}



	switch (nSig)

	{

	case AfxSig_vv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND)(); // 这里BN_CLICKED消息响应

		break;



	case AfxSig_bv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_bCOMMAND)();

		break;



	case AfxSig_vw:

		// normal command or control notification in a range

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND_RANGE)(nID);

		break;



	case AfxSig_bw:

		// extended command (passed ID, returns bContinue)

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_COMMAND_EX)(nID);

		break;



	case AfxSig_vNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_bNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_bNOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_vwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY_RANGE)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_bwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_NOTIFY_EX)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_cmdui:

		{

			// ON_UPDATE_COMMAND_UI or ON_UPDATE_COMMAND_UI_REFLECT case

			ASSERT(CN_UPDATE_COMMAND_UI == (UINT)-1);

			ASSERT(nCode == CN_UPDATE_COMMAND_UI || nCode == 0xFFFF);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI)(pCmdUI);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	case AfxSig_cmduiw:

		{

			// ON_UPDATE_COMMAND_UI case

			ASSERT(nCode == CN_UPDATE_COMMAND_UI);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(pCmdUI->m_nID == nID);           // sanity assert

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI_RANGE)(pCmdUI, nID);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	// general extensibility hooks

	case AfxSig_vpv:

		(pTarget->*mmf.pfn_OTHER)(pExtra);

		break;

	case AfxSig_bpv:

		bResult = (pTarget->*mmf.pfn_OTHER_EX)(pExtra);

		break;



	default:    // illegal

		ASSERT(FALSE);

		return 0;

	}

	return bResult;

}

看一下，这里，bResult默认值为TRUE，

Eleven 2011-12-27

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AFX_STATIC BOOL AFXAPI _AfxDispatchCmdMsg(CCmdTarget* pTarget, UINT nID, int nCode,

	AFX_PMSG pfn, void* pExtra, UINT nSig, AFX_CMDHANDLERINFO* pHandlerInfo)

		// return TRUE to stop routing

{

	ASSERT_VALID(pTarget);

	UNUSED(nCode);   // unused in release builds



	union MessageMapFunctions mmf;

	mmf.pfn = pfn;

	BOOL bResult = TRUE; // default is ok



	if (pHandlerInfo != NULL)

	{

		// just fill in the information, don't do it

		pHandlerInfo->pTarget = pTarget;

		pHandlerInfo->pmf = mmf.pfn;

		return TRUE;

	}



	switch (nSig)

	{

	case AfxSig_vv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND)(); // 这里BN_CLICKED消息响应

		break;



	case AfxSig_bv:

		// normal command or control notification

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_bCOMMAND)();

		break;



	case AfxSig_vw:

		// normal command or control notification in a range

		ASSERT(CN_COMMAND == 0);        // CN_COMMAND same as BN_CLICKED

		ASSERT(pExtra == NULL);

		(pTarget->*mmf.pfn_COMMAND_RANGE)(nID);

		break;



	case AfxSig_bw:

		// extended command (passed ID, returns bContinue)

		ASSERT(pExtra == NULL);

		bResult = (pTarget->*mmf.pfn_COMMAND_EX)(nID);

		break;



	case AfxSig_vNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_bNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_bNOTIFY)(pNotify->pNMHDR, pNotify->pResult);

		}

		break;

	case AfxSig_vwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			(pTarget->*mmf.pfn_NOTIFY_RANGE)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_bwNMHDRpl:

		{

			AFX_NOTIFY* pNotify = (AFX_NOTIFY*)pExtra;

			ASSERT(pNotify != NULL);

			ASSERT(pNotify->pResult != NULL);

			ASSERT(pNotify->pNMHDR != NULL);

			bResult = (pTarget->*mmf.pfn_NOTIFY_EX)(nID, pNotify->pNMHDR,

				pNotify->pResult);

		}

		break;

	case AfxSig_cmdui:

		{

			// ON_UPDATE_COMMAND_UI or ON_UPDATE_COMMAND_UI_REFLECT case

			ASSERT(CN_UPDATE_COMMAND_UI == (UINT)-1);

			ASSERT(nCode == CN_UPDATE_COMMAND_UI || nCode == 0xFFFF);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI)(pCmdUI);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	case AfxSig_cmduiw:

		{

			// ON_UPDATE_COMMAND_UI case

			ASSERT(nCode == CN_UPDATE_COMMAND_UI);

			ASSERT(pExtra != NULL);

			CCmdUI* pCmdUI = (CCmdUI*)pExtra;

			ASSERT(pCmdUI->m_nID == nID);           // sanity assert

			ASSERT(!pCmdUI->m_bContinueRouting);    // idle - not set

			(pTarget->*mmf.pfn_UPDATE_COMMAND_UI_RANGE)(pCmdUI, nID);

			bResult = !pCmdUI->m_bContinueRouting;

			pCmdUI->m_bContinueRouting = FALSE;     // go back to idle

		}

		break;



	// general extensibility hooks

	case AfxSig_vpv:

		(pTarget->*mmf.pfn_OTHER)(pExtra);

		break;

	case AfxSig_bpv:

		bResult = (pTarget->*mmf.pfn_OTHER_EX)(pExtra);

		break;



	default:    // illegal

		ASSERT(FALSE);

		return 0;

	}

	return bResult;

}

看一下，这里，bResult默认值为TRUE，

不二星空 2011-12-27

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[Quote=引用 7 楼 visualeleven 的回复:]
nState = ::SendMessage(this->m_hWnd, WM_COMMAND, IDC_BTN_TOGETSTAT, (LPARAM)btn_test.m_hWnd);
-->
nState = ::SendMessage(this->m_hWnd, WM_COMMAND, MAKEWPARAM(IDC_BTN_TOGETSTAT, BN_CLICKED), (LPARAM)……
[/Quote]

两个都可以实现点击功能，以前用的是下面那种。。后面发现BN_CLICKED可以不填，干脆简化了

不二星空 2011-12-27

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Eleven 2011-12-27

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nState = ::SendMessage(this->m_hWnd, WM_COMMAND, IDC_BTN_TOGETSTAT, (LPARAM)btn_test.m_hWnd);
-->
nState = ::SendMessage(this->m_hWnd, WM_COMMAND, MAKEWPARAM(IDC_BTN_TOGETSTAT, BN_CLICKED), (LPARAM)btn_test.m_hWnd);

Eleven 2011-12-27

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Eleven 2011-12-27

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不二星空 2011-12-27

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[Quote=引用 1 楼 oyljerry 的回复:]
返回值：返回值指定消息处理的结果，依赖于所发送的消息。
http://baike.baidu.com/view/1080187.htm
[/Quote]
这个我明白，所以我才问WM_COMMAND这个消息我查的就是WM_COMMAND这个消息.

不二星空 2011-12-27

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关于WM_COMMAND消息的返回值的问题，求高人指点~~~~~~

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