在头文件CXXXDlg.h中青年人网站提示:定义一个编辑框类CLimitLengthEdit
class CLimitLengthEdit : public CWindowImpl<CLimitLengthEdit , CEdit>
{
public:
CLimitLengthEdit() {};
virtual ~CLimitLengthEdit(){};
BOOL SubclassWindow(HWND hWnd) {typedef CWindowImpl<CLimitLengthEdit , CEdit> CWindowBase;return CWindowBase::SubclassWindow(hWnd);};
protected:
BEGIN_MSG_MAP(CLimitLengthEdit)
END_MSG_MAP()
};
在CXXXDlg.h中CXXXDlg类的定义处加入消息映射以及响应函数声明
protected:
BEGIN_MSG_MAP(CRequestDlg)
MESSAGE_HANDLER(WM_INITDIALOG, OnInitDialog)
COMMAND_HANDLER(IDC_EDIT_MESSAGE,EN_CHANGE,OnEditChange) //IDC_EDIT_MESSAGE为编辑控件的ID
REFLECT_NOTIFICATIONS_EX()
END_MSG_MAP()
LRESULT OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/);
LRESULT OnEditChange(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/);
加入成员变量
private：
CLimitLengthEdit m_llEdit;
在实现文件CXXXDlg.cpp中加入消息处理函数
#define MAX_LIMIT_LEN 20 //青年人网站提示:字符长度限制为中文10个，英文20个
LRESULT CRequestDlg::OnInitDialog(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
{
m_llEdit.SubclassWindow(GetDlgItem(IDC_EDIT_MESSAGE));
::SetFocus(GetDlgItem(IDC_EDIT_MESSAGE));
return 0;
}
LRESULT CRequestDlg::OnEditChange(WORD /*wNotifyCode*/, WORD wID, HWND /*hWndCtl*/, BOOL& /*bHandled*/)
{
CString strText;
TCHAR msg[128];
m_llEdit.GetWindowText(msg , 128);
strText.Format(_T("%s"),msg);
int nPixelPos = 0;
int nCount = 0;
int pos = 0;
int iLen = strText.GetLength();
for(int i = 0; i < iLen;)
{
if(IsDBCSLeadByte(strText[i]))
{
nCount ++;
i += 2;
if(i > 20)
{
HideCaret();
m_llEdit.SetSel(0,-1);
m_llEdit.ReplaceSel(strText.Left(i - 2));
ShowCaret();
m_llEdit.SetLimitText(nCount);
break;
}
else
{
m_llEdit.SetLimitText(20);
}
}
else
{
nCount ++;
i++;
if(i > 20)
{
HideCaret();
m_llEdit.SetSel(0,-1);
m_llEdit.ReplaceSel(strText.Left(i - 1));
ShowCaret();
m_llEdit.SetLimitText(nCount);
break;
}
else
{
m_llEdit.SetLimitText(20);
}
}
}
strText.ReleaseBuffer();
return FALSE;
}
责任编辑：小草
