VC++ 编辑框只输入数字

男娘i 2022-06-17 08:59 315阅读 0赞

子类化CEdit为CNewEdit；处理CNewEdit的消息WM\_CHAR。其中

void CNewEdit::OnChar(UINT nChar, UINTnRepCnt, UINT nFlags) 如下；

其它需要可以灵活定制。

void CNewEdit::OnChar(UINT nChar, UINTnRepCnt, UINT nFlags)  
\{  
if(nChar==VK\_BACK)//BackSpace  
CEdit::OnChar(nChar, nRepCnt,nFlags);

//  
//Some invariable parameter for further use  
CPoint caretPt;  
caretPt=GetCaretPos ();  
caretPt.x = LOWORD (CharFromPos (caretPt));//Thefunction is the core,I'm blind to seek it for 3 days

CString str;  
int nLength;  
int nDot;  
int neE;  
double fabstr;  
GetWindowText (str);  
fabstr=fabs(atof(str));  
nLength=str.GetLength();  
nDot=str.Find(\_T('.'));  
neE=max(str.Find('e'),str.Find('E'));  
  
  
  
//  
//Input 0-9,especialy 0 needs moreattention.

if (isdigit(nChar))  
\{  
if(nChar>'0')  
CEdit::OnChar(nChar, nRepCnt,nFlags);

else//make use of '0'  
\{  
if(str.IsEmpty())  
\{  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
return;  
\}  
  
if(str\[0\]=='0')  
\{  
if(neE==-1)  
\{  
if(caretPt.x>1)  
\{  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
return;  
\}  
else  
return;  
\}  
else  
\{  
  
if((caretPt.x-1)!=neE&& caretPt.x>1)  
\{  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
return;  
\}  
else  
return;  
\}

\}  
  
  
if(str\[0\]=='-')  
\{  
if(str\[1\]=='0')  
\{  
if(neE==-1)  
\{  
if(caretPt.x>2)  
\{  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
return;  
\}  
else  
return;  
\}  
else  
\{  
if((caretPt.x-1)!=neE&& caretPt.x>2)  
\{  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
return;  
\}  
else  
return;  
\}

\}  
  
  
\}  
  
if(str\[0\]>='1'&& caretPt.x>0)  
\{  
  
CEdit::OnChar(nChar,nRepCnt, nFlags);

return;  
\}

\}  
\}  
  
  
  
  
else  
  
//  
//Determine the '-'  
if (nChar == '-')  
\{  
if(!caretPt.x)  
\{  
if(((nLength > 0) && (str\[0\]!='-')) || (nLength==0))  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
\}  
else  
\{  
if ((str\[caretPt.x-1\] == 'e') || (str \[caretPt.x-1\] == 'E'))  
CEdit::OnChar(nChar,nRepCnt, nFlags);  
\}  
\}

else  
  
  
//Input'e' or 'E'  
  
if ((nChar == 'e') || (nChar =='E'))  
\{  
if((caretPt.x == 1) && (str\[0\] == '-'))  
return;

if(caretPt.x)  
\{  
if(neE!=-1)  
return;  
if(nDot!=-1&& caretPt.x<nDot)  
return;

CEdit::OnChar(nChar,nRepCnt, nFlags);  
\}  
\}

else

//  
//Input '.'  
if (nChar == '.')  
\{  
if(nDot!=-1)  
return;  
  
if(neE!=-1&& caretPt.x>neE)  
return;

CEdit::OnChar(nChar,nRepCnt, nFlags);  
\}

此外如果要截取输入字符串末尾的‘0';可以利用消息WM\_KILLFOCUS;

函数代码如下：

void CNewEdit::OnKillfocus()  
\{  
// TODO: Add your control notification handlercode here  
CString str,tr;  
GetWindowText(str);  
int nLength;  
intnDot=-1;  
int neE;  
//double fstr;  
nLength=str.GetLength();  
  
  
  
for(int i=0;i<nLength;i++)  
\{  
if(str\[i\]==\_T('.'))  
nDot=i;  
\}  
  
neE=max(str.Find(\_T('e')),str.Find(\_T('E')));  
  
  
  
if(nDot!=-1 && neE==-1)  
str.TrimRight(\_T("0"));  
\{  
int t= str.Find('.');  
  
  
if(t==str.GetLength()-1)  
str+='0';  
\}

SetWindowText(str);  
\}