void CtestDlg::OnBnClickedButton1()
{
    wchar_t a1[12], a2[12], a3[12]; 

    //方法一 GetWindowText
    //GetDlgItem(IDC_EDIT_1)->GetWindowText(a1,12);
    //GetDlgItem(IDC_EDIT_2)->GetWindowText(a2, 12);
    //_itow_s(_wtoi(a1) + _wtoi(a2),a3,10);
    //SetDlgItemText(IDC_EDIT_3, a3);

    //方法二 GetDlgItemText
    //GetDlgItemText(IDC_EDIT_1,a1,12);
    //GetDlgItemText(IDC_EDIT_2, a2,12);
    //_itow(_wtoi(a1) + _wtoi(a2), a3, 10);
    //SetDlgItemText(IDC_EDIT_3, a3);

    //方法三 GetDlgItemInt
    //int a = GetDlgItemInt(IDC_EDIT_1);
    //int b = GetDlgItemInt(IDC_EDIT_2);
    //SetDlgItemText(IDC_EDIT_3, _itow(a + b, a3, 10));

    //方法四

}