注：
        m_edit1代表ID为IDC_EDIT1的CEdit控件的control类型的变量
        m_richedit1代表ID为IDC_RICHEDIT1的CRichEditCtrl控件的control类型的变量

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1.设置edit只读属性

方法一：
                m_edit1.SetReadOnly(TRUE);
    方法二：
                ::SendMessage(m_edit1.m_hWnd, EM_SETREADONLY, TRUE, 0);

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2.判断edit中光标状态并得到选中内容(richedit同样适用)

int nStart, nEnd;
        CString strTemp;

m_edit1.GetSel(nStart, nEnd);
        if(nStart == nEnd)
        {
            strTemp.Format(_T("光标在%d"), nStart);
            AfxMessageBox(strTemp);
        }
        else
        {
            //得到edit选中的内容    
            m_edit1.GetWindowText(strTemp);
            strTemp = strTemp.Mid(nStart) - strTemp.Mid(nEnd);
            AfxMessageBox(strTemp);
        }
    注：GetSel后，如果nStart和nEnd，表明光标处于某个位置（直观来看就是光标在闪动）；
             如果nStart和nEnd不相等，表明用户在edit中选中了一段内容。

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3.在edit最后添加字符串

CString str;
        m_edit1.SetSel(-1, -1);
        m_edit1.ReplaceSel(str);

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4.随输入自动滚动到最后一行(richedit同样适用)

方法一：（摘自msdn）
        // The pointer to my edit.
        extern CEdit* pmyEdit;
        int nFirstVisible = pmyEdit->GetFirstVisibleLine();

// Scroll the edit control so that the first visible line
        // is the first line of text.
        if (nFirstVisible > 0)
        {
            pmyEdit->LineScroll(-nFirstVisible, 0);
        }
    方法二：
        m_richedit.PostMessage(WM_VSCROLL, SB_BOTTOM, 0);

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5.如何限制edit输入指定字符

可以从CEdit派生一个类，添加WM_CHAR消息映射。下面一个例子实现了限定输入16进制字符的功能。

void CMyHexEdit::OnChar(UINT nChar, UINT nRepCnt, UINT nFlags) 
   {
        if ( (nChar >= '0' && nChar <= '9') ||
             (nChar >= 'a' && nChar <= 'f') ||
             (nChar >= 'A' && nChar <= 'F') ||
              nChar == VK_BACK || 
              nChar == VK_DELETE)    //msdn的virtual key
       {
            CEdit::OnChar(nChar, nRepCnt, nFlags);
        }     
   }

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6.如何使用richedit

添加AfxInitRichEdit();
       CxxxApp::InitInstance()
        {
             AfxInitRichEdit();
          .............
       }

AfxInitRichEdit()功能：装载 RichEdit 1.0 Control (RICHED32.DLL).

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7.如何使用richedit2.0 or richedit3.0

使用原因：由于RichEdit2.0A自动为宽字符（WideChar），所以它可以解决中文乱码以及一些汉字问题

方法一：（msdn上的做法，适用于用VC.NET及以后版本创建的工程）
            To update rich edit controls in existing Visual C++ applications to version 2.0,
            open the .RC file as text, change the class name of each rich edit control from   "RICHEDIT" to  "RichEdit20a".
            Then replace the call to AfxInitRichEdit with AfxInitRichEdit2.
    方法二：以对话框为例：
       (1)    增加一全局变量 HMODULE hMod;
       (2)    在CxxxApp::InitInstance()中添加一句hMod = LoadLibrary(_T("riched20.dll"));
              在CxxxApp::ExitInstance()中添加一句FreeLibrary(hMod);
       (3)      在对话框上放一个richedit，文本方式打开.rc文件修改该richedit控件的类名"RICHEDIT" to  "RichEdit20a".
       (4)      在对话框头文件添加 CRichEditCtrl m_richedit;
              在OnInitDialog中添加 m_richedit.SubclassDlgItem(IDC_RICHEDIT1, this);

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8.改变richedit指定区域的颜色及字体

CHARFORMAT cf;
        ZeroMemory(&cf, sizeof(CHARFORMAT));
        cf.cbSize = sizeof(CHARFORMAT);
        cf.dwMask = CFM_BOLD | CFM_COLOR | CFM_FACE |
                            CFM_ITALIC | CFM_SIZE | CFM_UNDERLINE;
        cf.dwEffects = 0;
        cf.yHeight = 12*12;//文字高度
        cf.crTextColor = RGB(200, 100, 255); //文字颜色
        strcpy(cf.szFaceName ,_T("隶书"));//设置字体
    
        m_richedit1.SetSel(1, 5); //设置处理区域
        m_richedit1.SetSelectionCharFormat(cf);

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9.设置行间距（只适用于richedit2.0）

PARAFORMAT2 pf;
        pf2.cbSize = sizeof(PARAFORMAT2);
        pf2.dwMask = PFM_LINESPACING | PFM_SPACEAFTER;
        pf2.dyLineSpacing = 200;
        pf2.bLineSpacingRule  = 4;
        m_richedit.SetParaFormat(pf2);

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10.richedit插入位图

Q220844：How to insert a bitmap into an RTF document using the RichEdit control in Visual C++ 6.0
http://support.microsoft.com/default.aspx?scid=kb;en-us;220844
http://www.codeguru.com/Cpp/controls/richedit/article.php/c2417/
http://www.codeguru.com/Cpp/controls/richedit/article.php/c5383/

11.richedit插入gif动画

http://www.codeproject.com/richedit/AnimatedEmoticon.asp

12.richedit嵌入ole对象

http://support.microsoft.com/kb/141549/en-us

13.使richedit选中内容只读

http://www.codeguru.com/cpp/controls/richedit/article.php/c2401/

14.打印richedit

http://www.protext.com/MFC/RichEdit3.htm

15.richeidt用于聊天消息窗口

http://www.vckbase.com/document/viewdoc/?id=1087
http://www.codeproject.com/richedit/chatrichedit.asp
http://www.codeguru.com/Cpp/controls/richedit/article.php/c2395/

16.解决richedit的EN_SETFOCUS和EN_KILLFOCUS无响应的问题

http://support.microsoft.com/kb/181664/en-us

17.richedit拼写检查

http://www.codeproject.com/com/AutoSpellCheck.asp

18.改变edit背景色

Q117778：How to change the background color of an MFC edit control
http://support.microsoft.com/kb/117778/en-us

19.当edit控件的父窗口属性是带标题栏WS_CAPTION和子窗口WS_CHILD时，不能设置焦点SetFocus

Q230587：PRB: Can't Set Focus to an Edit Control When its Parent Is an Inactive Captioned Child Window

http://support.microsoft.com/kb/230587/en-us

20. 在Edit中回车时，会退出对话框

选中Edit的风格Want Return。

MSDN的解释如下：
ES_WANTRETURN   Specifies that a carriage return be inserted when the user presses the ENTER key while entering text into a multiple-line edit control in a dialog box. Without this style, pressing the ENTER key has the same effect as pressing the dialog box's default pushbutton. This style has no effect on a single-line edit control.

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21. 动态创建的edit没有边框的问题

m_edit.Create(....);
    m_edit.ModifyStyleEx(0, WS_EX_CLIENTEDGE, SWP_DRAWFRAME);

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22. 一个能显示RTF，ole（包括gif， wmv，excel ，ppt）的例子

http://www.codeproject.com/richedit/COleRichEditCtrl.asp