我要把一个文本框里输入的信息通过按钮转移到另一个文本筐里:
void CMy20070907_wuDlg::OnBtnand() //"And"
{
    // TODO: Add your control notification handler code here
    CString str;
    m_Txtinput.GetWindowText(str);
    m_Txtinput.SetWindowText(str + CString("&"));
    
}
void CMy20070907_wuDlg::OnBtnimp() // "->"
{
    // TODO: Add your control notification handler code here
    CString str;
    m_Txtinput.GetWindowText(str);
    m_Txtinput.SetWindowText(str + CString("->"));
    
}
void CMy20070907_wuDlg::OnBtnminus() //"-"
{
    // TODO: Add your control notification handler code here
    CString str;
    m_Txtinput.GetWindowText(str);
    m_Txtinput.SetWindowText(str + CString("-"));
    
}
void CMy20070907_wuDlg::OnBtnor()  // "||"
{
    // TODO: Add your control notification handler code here
    CString str;
    m_Txtinput.GetWindowText(str);
    m_Txtinput.SetWindowText(str + CString("||"));
    
}
void CMy20070907_wuDlg::OnChangeTxtInput() 
{
    // 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
    
}
void CMy20070907_wuDlg::OnbtnEnt() //">>"
{
    // TODO: Add your control notification handler code here
    CString str1, str2;
    m_Editcondition.GetWindowText(str2);
    m_Editcondition.SetWindowText(str2 + m_Txtinput.GetWindowText(str1));
}
然后error中说:error C2679: binary '+' : no operator defined which takes a right-hand operand of type 'void' (or there is no acceptable conversion) 怎么办呢?
怎么办呢?

 
											





 
	    


