MFC ocx GetDlgItem的问题

//控件调整大小位置在这个消息内

//

void DialogMain::OnShowWindow(BOOL bShow, UINT nStatus)

{

    CDialog::OnShowWindow(bShow, nStatus);



    // TODO: 在此处添加消息处理程序代码

    

    //五个按钮组成的区域是一个整体，相对坐标为0 0

    //各个按钮缝隙为5



    int X = 0 + 825;      //初始875

    int Y = 0 + 150;      //初始150



    //位置和大小

    CWnd *pWnd = GetDlgItem(IDC_BUTTON_UP);

    pWnd->SetWindowPos(NULL,X+55,Y,50,50,NULL);



    pWnd = GetDlgItem(IDC_BUTTON_LEFT);

    pWnd->SetWindowPos(NULL,X,Y+55,50,50,NULL);



    pWnd = GetDlgItem(IDC_BUTTON_RIGHT);

    pWnd->SetWindowPos(NULL,X+110,Y+55,50,50,NULL);



    pWnd = GetDlgItem(IDC_BUTTON_DOWN);

    pWnd->SetWindowPos(NULL,X+55,Y+110,50,50,NULL);



    pWnd = GetDlgItem(IDC_BUTTON_AUTO);

    pWnd->SetWindowPos(NULL,X+55,Y+55,50,50,NULL);



    //加载图片

    HBITMAP hBitmap = LoadBitmap(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDB_BITMAP_UP));

    CButton *cbutton = (CButton *)GetDlgItem(IDC_BUTTON_UP);

    cbutton->SetBitmap(hBitmap);



    hBitmap = LoadBitmap(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDB_BITMAP_LEFT));

    cbutton = (CButton *)GetDlgItem(IDC_BUTTON_LEFT);

    cbutton->SetBitmap(hBitmap);



    hBitmap = LoadBitmap(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDB_BITMAP_RIGHT));

    cbutton = (CButton *)GetDlgItem(IDC_BUTTON_RIGHT);

    cbutton->SetBitmap(hBitmap);



    hBitmap = LoadBitmap(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDB_BITMAP_DOWN));

    cbutton = (CButton *)GetDlgItem(IDC_BUTTON_DOWN);

    cbutton->SetBitmap(hBitmap);



    hBitmap = LoadBitmap(AfxGetInstanceHandle(),MAKEINTRESOURCE(IDB_BITMAP_AUTO));

    cbutton = (CButton *)GetDlgItem(IDC_BUTTON_AUTO);

    cbutton->SetBitmap(hBitmap);





    //加载背景图片

    CBitmap bmp;  

    bmp.LoadBitmap(IDB_BITMAP_BK);

    m_brush.CreatePatternBrush(&bmp);  





    PIC = GetDlgItem(IDC_ANIMATE_VIDEO);



}