www.gusucode.com > VC++ COleDropTarget扩展类来支持任意窗口拖放，文本拖动-源码程 > VC++ COleDropTarget扩展类来支持任意窗口拖放，文本拖动-源码程序/code/DropButton.cpp

    // DropButton.cpp : implementation file
// Download by http://www.NewXing.com

#include "stdafx.h"
#include "dropexdemo.h"
#include "DropButton.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CDropButton

CDropButton::CDropButton()
{
}

CDropButton::~CDropButton()
{
}


BEGIN_MESSAGE_MAP(CDropButton, CButton)
	//{{AFX_MSG_MAP(CDropButton)
		// NOTE - the ClassWizard will add and remove mapping macros here.
	//}}AFX_MSG_MAP
	ON_MESSAGE(DROPM_DRAGOVER,OnDragOver)
	ON_MESSAGE(DROPM_DROPEX,OnDropEx)
	ON_MESSAGE(DROPM_DROP,OnDrop)
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDropButton message handlers
BOOL CDropButton::Register()
{
	return m_dropEx.Register( this );
}

DROPEFFECT CDropButton::OnDragOver(WPARAM pDropInfoClass, LPARAM lParm)
{
	COleDropInfo* pInfo = (COleDropInfo* )pDropInfoClass;
	ASSERT(pInfo->IsKindOf(RUNTIME_CLASS(COleDropInfo)));

	if( pInfo->m_pDataObject->IsDataAvailable( CF_TEXT ) )
		return DROPEFFECT_COPY;
	else
		return DROPEFFECT_NONE;
}

DROPEFFECT CDropButton::OnDropEx(WPARAM pDropInfoClass, LPARAM lParm)
{
	return (DROPEFFECT)-1;
}

BOOL CDropButton::OnDrop(WPARAM pDropInfoClass, LPARAM lParm)
{
	COleDropInfo* pInfo = (COleDropInfo* )pDropInfoClass;
	ASSERT(pInfo->IsKindOf(RUNTIME_CLASS(COleDropInfo)));

	if( pInfo->m_pDataObject->IsDataAvailable( CF_TEXT ) )
	{
		HGLOBAL hMem = pInfo->m_pDataObject->GetGlobalData( CF_TEXT );
		char* lp = (char *)GlobalLock((HGLOBAL) hMem);//lock source
		if (lp != NULL)
		{
			//Set Windows title with Drop text 
			SetWindowText( lp );
		}
		GlobalUnlock( hMem );//unlock source
		return TRUE;
	}
	else
		return FALSE;
}