VC++ 编辑框只输入数字

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)
{
<wbr>if(nChar==VK_BACK)//BackSpace<br><wbr><wbr>CEdit::OnChar(nChar, nRepCnt,nFlags);<br><wbr><wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr>

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

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

<wbr>if (isdigit(nChar))<br><wbr>{<br><wbr><wbr>if(nChar&gt;'0')<wbr><br><wbr><wbr>CEdit::OnChar(nChar, nRepCnt,nFlags);</wbr></wbr></wbr></wbr></wbr></wbr></wbr>

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

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

<wbr><wbr><wbr><wbr><wbr>}<br><wbr><wbr><br><wbr><wbr><wbr><wbr><br><wbr><wbr><wbr><wbr>}<br><wbr><wbr><wbr><br><wbr><wbr><wbr>if(str[0]&gt;='1'&amp;&amp; caretPt.x&gt;0)<br><wbr><wbr><wbr>{<wbr><wbr><br><wbr><wbr><wbr><wbr><br><wbr><wbr><wbr><wbr>CEdit::OnChar(nChar,nRepCnt, nFlags);</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><wbr><wbr><wbr>return;<br><wbr><wbr><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr><br><wbr><wbr><br><wbr><wbr><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

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

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

<wbr><wbr>if(caretPt.x)<br><wbr><wbr>{<br><wbr><wbr><wbr><wbr>if(neE!=-1)<br><wbr><wbr><wbr><wbr><wbr>return;<br><wbr><wbr><wbr>if(nDot!=-1&amp;&amp; caretPt.x&lt;nDot)<br><wbr><wbr><wbr><wbr>return;</wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr><wbr>CEdit::OnChar(nChar,nRepCnt, nFlags);<br><wbr><wbr>}<br><wbr>}</wbr></wbr></wbr></wbr></wbr></wbr>

<wbr>else</wbr>

<wbr><wbr>//////////////////////////////////////////////////////<br><wbr><wbr>//Input '.'<br><wbr><wbr>if (nChar == '.')<br><wbr><wbr>{<br><wbr><wbr><wbr>if(nDot!=-1)<br><wbr><wbr><wbr><wbr>return;<br><wbr><wbr><br><wbr><wbr><wbr>if(neE!=-1&amp;&amp; caretPt.x&gt;neE)<br><wbr><wbr><wbr><wbr>return;<br><wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr></wbr>

<wbr><wbr>CEdit::OnChar(nChar,nRepCnt, nFlags);<br><wbr>}</wbr></wbr></wbr>

<wbr>此外如果要截取输入字符串末尾的‘0';可以利用消息WM_KILLFOCUS;</wbr>

函数代码如下：

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

<wbr><br><wbr>SetWindowText(str);<br> }</wbr></wbr>