类似 MSN 信息发送框的制作(上)

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一、引言
　　 用 MSN 和 QQ 等聊天的时候,当用户输入特定意义的字符串时,系统回自动用一张小图片替代.比如输入" : ) "系统
会用一个小笑脸代替。我要实现的就是这样一个信息输入框 。这个信息输入框由两部分组成:图案选择器和多功能文本框。本篇介绍多功能文本框。

二、原理简介

1、主要功能用CRichEditCtrl实现,像设置字体,设置字体颜色,字号等等CRichEditCtrl都提供了很完善的支持，我就不一一赘述了。

CRichEditCtrl 主要的不足在于以下几个方面：

(1).没有右键菜单

(2).不能插入图片(这是实现转义字符显示的关键)

(3).RTF格式输入输出不够方便(涉及到回调函数的递归调用)

　　 我扩展了CRichEditCtrl类CRichEditCtrlEx实现了上述功能.参考了很多网上的文章，对所有公开源码的开发人员表示崇高的敬意!!

2、实现右键菜单:

///生成右键菜单

void CRichEditCtrlEx::OnRButtonUp(UINT nFlags, CPoint point) 

{

	// TODO: Add your message handler code here and/or call default

	//设置为焦点

	SetFocus();

	//创建一个弹出式菜单

	CMenu popmenu;

	popmenu.CreatePopupMenu();

	//添加菜单项目

	popmenu.AppendMenu(0, ID_RICH_UNDO, "&Undo");

	popmenu.AppendMenu(0, MF_SEPARATOR);

	popmenu.AppendMenu(0, ID_RICH_CUT, "&Cut");

	popmenu.AppendMenu(0, ID_RICH_COPY, "C&opy");

	popmenu.AppendMenu(0, ID_RICH_PASTE, "&Paste");

	popmenu.AppendMenu(0, ID_RICH_CLEAR, "C&lear");

	popmenu.AppendMenu(0, MF_SEPARATOR);

	popmenu.AppendMenu(0, ID_RICH_SELECTALL, "Select &All");

	popmenu.AppendMenu(0, MF_SEPARATOR);

	popmenu.AppendMenu(0, ID_RICH_SETFONT, "Select &Font");

	

	//初始化菜单项

	UINT nUndo=(CanUndo() ? 0 : MF_GRAYED );

	popmenu.EnableMenuItem(ID_RICH_UNDO, MF_BYCOMMAND|nUndo);

	

	UINT nSel=((GetSelectionType()!=SEL_EMPTY) ? 0 : MF_GRAYED) ;

	popmenu.EnableMenuItem(ID_RICH_CUT, MF_BYCOMMAND|nSel);

	popmenu.EnableMenuItem(ID_RICH_COPY, MF_BYCOMMAND|nSel);

	popmenu.EnableMenuItem(ID_RICH_CLEAR, MF_BYCOMMAND|nSel);

	

	UINT nPaste=(CanPaste() ? 0 : MF_GRAYED) ;

	popmenu.EnableMenuItem(ID_RICH_PASTE, MF_BYCOMMAND|nPaste);

	

	//显示菜单

	CPoint pt;

	GetCursorPos(&pt);

	popmenu.TrackPopupMenu(TPM_RIGHTBUTTON, pt.x, pt.y, this);

	popmenu.DestroyMenu();

	CRichEditCtrl::OnRButtonDown(nFlags, point);

	CRichEditCtrl::OnRButtonUp(nFlags, point);

}

3、关于如何把图片插入到RichEdit中,国外由很多文章介绍,都是(我看到的都是)通过插入OLE对象来实现.主要用两个函数，还涉及到了和多接口的调用。

(1)从文件创建OLE对象OleCreateFromFile();

void CRichEditCtrlEx::InsertBitmap(CString szFileName)

{

	USES_CONVERSION;

	SCODE sc = ::CreateILockBytesOnHGlobal(NULL, TRUE, &m_lpLockBytes);

	if (sc != S_OK)

		AfxThrowOleException(sc);

	ASSERT(m_lpLockBytes != NULL);

	

	sc = ::StgCreateDocfileOnILockBytes(m_lpLockBytes,

		STGM_SHARE_EXCLUSIVE|STGM_CREATE|STGM_READWRITE, 0, &m_lpStorage);

	if (sc != S_OK)

	{

		VERIFY(m_lpLockBytes->Release() == 0);

		m_lpLockBytes = NULL;

		AfxThrowOleException(sc);

	}

	

	// attempt to create the object

	sc = ::OleCreateFromFile(CLSID_NULL, T2COLE(szFileName),

        IID_IUnknown, OLERENDER_DRAW, NULL, NULL, 

        m_lpStorage, (void **)&m_lpObject);

	if ( sc != S_OK )

	{

		TCHAR * lpMsgBuf;

		::FormatMessage( FORMAT_MESSAGE_ALLOCATE_BUFFER | 

			FORMAT_MESSAGE_FROM_SYSTEM, NULL, 

			::GetLastError(),

			MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT),

			(LPTSTR) &lpMsgBuf, 0, NULL );

		CString msg( lpMsgBuf );

		msg  = _T("\n\n\nThe following file, created in\n"

			"Simulation->Plot, may be missing due\n"

			"to not doing a File->Save Workspace:\n\n" );

		msg  = szFileName;

		AfxMessageBox( msg, MB_OK );

		::LocalFree( lpMsgBuf );

		return;

	}

	

	// m_lpObject is currently an IUnknown, convert to IOleObject

	if (m_lpObject != NULL)

	{

		LPUNKNOWN lpUnk = m_lpObject;

		m_lpObject = QUERYINTERFACE(lpUnk, IOleObject);

		lpUnk->Release();

		if (m_lpObject == NULL)

			AfxThrowOleException(E_OUTOFMEMORY);

	}

	

	// cache the IViewObject interface

	m_lpViewObject = QUERYINTERFACE(m_lpObject, IViewObject2);

	if (m_lpViewObject == NULL)

		return;

	

	// setup for advises; we assume that OLE cleans them up properly

	LPADVISESINK lpAdviseSink =

		(LPADVISESINK)GetInterface(&IID_IAdviseSink);

	

	// set up view advise

	VERIFY(m_lpViewObject->SetAdvise(DVASPECT_CONTENT, 0, lpAdviseSink)

		== S_OK);

	

	// the server shows these in its user-interface

	//  (as document title and in File Exit menu)

	m_lpObject->SetHostNames(T2COLE(AfxGetAppName()),

		T2COLE(_T("Test")));

	

	// all items are "contained" -- this makes our reference to this object

	//  weak -- which is needed for links to embedding silent update.

	OleSetContainedObject(m_lpObject, TRUE);

	

	CHARRANGE cr;

	this->GetSel( cr );

	cr.cpMin = cr.cpMax -1;

	this->SetSel( cr );

	

	REOBJECT reo;

	memset( &reo, 0, sizeof( reo ) );

	reo.cbStruct = sizeof( reo );

	CLSID classID;

	if ( m_lpObject->GetUserClassID( &classID ) != S_OK)

		classID = CLSID_NULL;

	reo.clsid = classID;

	reo.cp = REO_CP_SELECTION;

	reo.poleobj = m_lpObject;

	reo.pstg = m_lpStorage;

	LPOLECLIENTSITE lpClientSite;

	this->GetIRichEditOle()->GetClientSite( &lpClientSite );

	reo.polesite = lpClientSite;

	SIZEL sizel;

	sizel.cx = sizel.cy = 0; // let richedit determine initial size

	reo.sizel = sizel;

	reo.dvaspect = DVASPECT_CONTENT;

	reo.dwFlags = REO_RESIZABLE;

	reo.dwUser = 0;

	HRESULT hr = this->GetIRichEditOle()->InsertObject( &reo );

	

}

(2)根据位图句柄创建OleCreateStaticFromData();用这个函数可以把资源中的图片插入到文本框中

void CRichEditCtrlEx::InsertBitmap(HBITMAP hBitmap)

{

	STGMEDIUM stgm;

	stgm.tymed = TYMED_GDI;    // Storage medium = HBITMAP handle

	stgm.hBitmap = hBitmap;

	stgm.pUnkForRelease = NULL; // Use ReleaseStgMedium

	

	FORMATETC fm;

	fm.cfFormat = CF_BITMAP;    // Clipboard format = CF_BITMAP

	fm.ptd = NULL;       // Target Device = Screen

	fm.dwAspect = DVASPECT_CONTENT;   // Level of detail = Full content

	fm.lindex = -1;       // Index = Not applicaple

	fm.tymed = TYMED_GDI;  

	

	////创建输入数据源

	IStorage *pStorage; 

	

	///分配内存

	LPLOCKBYTES lpLockBytes = NULL;

	SCODE sc = ::CreateILockBytesOnHGlobal(NULL, TRUE, &lpLockBytes);

	if (sc != S_OK)

		AfxThrowOleException(sc);

	ASSERT(lpLockBytes != NULL);

	

	sc = ::StgCreateDocfileOnILockBytes(lpLockBytes,

		STGM_SHARE_EXCLUSIVE|STGM_CREATE|STGM_READWRITE, 0, &pStorage);

	if (sc != S_OK)

	{

		VERIFY(lpLockBytes->Release() == 0);

		lpLockBytes = NULL;

		AfxThrowOleException(sc);

	}

	ASSERT(pStorage != NULL);

	

	COleDataSource *pDataSource = new COleDataSource;

	pDataSource->CacheData(CF_BITMAP, &stgm);

	LPDATAOBJECT lpDataObject = 

		(LPDATAOBJECT)pDataSource->GetInterface(&IID_IDataObject);

	

	///获取RichEdit的OLEClientSite

	LPOLECLIENTSITE lpClientSite;

	this->GetIRichEditOle()->GetClientSite( &lpClientSite );

	

	

	///创建OLE对象

	IOleObject *pOleObject;

	sc = OleCreateStaticFromData(lpDataObject,IID_IOleObject,OLERENDER_FORMAT,

		&fm,lpClientSite,pStorage,(void **)&pOleObject);

	if(sc!=S_OK)

		AfxThrowOleException(sc);

	

	///插入OLE对象

	

	REOBJECT reobject;

	ZeroMemory(&reobject, sizeof(REOBJECT));

	reobject.cbStruct = sizeof(REOBJECT);

	

	CLSID clsid;

	sc = pOleObject->GetUserClassID(&clsid);

	if (sc != S_OK)

		AfxThrowOleException(sc);

	

	reobject.clsid = clsid;

	reobject.cp = REO_CP_SELECTION;

	reobject.dvaspect = DVASPECT_CONTENT;

	reobject.poleobj = pOleObject;

	reobject.polesite = lpClientSite;

	reobject.pstg = pStorage;

	

	HRESULT hr = this->GetIRichEditOle()->InsertObject( &reobject );

	

}

4、读取/写入RTF格式字符串
　　CRichEditCtrl 提供了两个函数StreamIn()和StreamOut()来实现这个功能,输出的内容包含文本信息和字体信息。我把这两个函数重新包装了一下 ，用GetRTF()把格式文本返回到一个CString变量中SetRTF(CString )实现逆过程。具体代码参看本文附带的工程文件。

三、到此，这个多功能文本框就已经基本能满足我的要求了。但是如何选择表情符号? 如何自动替换? 还是个问题。(待续)
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