对话框字符过滤问题

IDC_EDIT1下字符过滤，仅仅16进制允许，

如何在编辑框里限制输入只能是16进制数字？
从网上找了点答案，具体是
从CEdit派生一个类，添加WM_CHAR消息映射。
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);
}
}

但是具体如何调用呢，
void CToolDlg::OnChangeEdit1()
{
    // TODO: If this is a RICHEDIT control, the control will not
    // send this notification unless you override the CDialog::OnInitDialog()
    // function and call CRichEditCtrl().SetEventMask()
    // with the ENM_CHANGE flag ORed into the mask.
   
    // TODO: Add your control notification handler code here
//   这类如何调用才能让IDC_EDIT1 有这个效果，谢谢

}