dynamically modifu drop-down combobox

void SetDropDownHeight(CComboBox* pMyComboBox, int itemsToShow)
{
    //Get rectangles
    CRect rctComboBox, rctDropDown;
    //Combo rect
    pMyComboBox->GetClientRect(&rctComboBox);
    //DropDownList rect
    pMyComboBox->GetDroppedControlRect(&rctDropDown);

    //Get Item height
    int itemHeight = pMyComboBox->GetItemHeight(-1);
    //Converts coordinates
    pMyComboBox->GetParent()->ScreenToClient(&rctDropDown);
    //Set height
    rctDropDown.bottom = rctDropDown.top + rctComboBox.Height() + itemHeight*itemsToShow;
    //apply changes
    pMyComboBox->MoveWindow(&rctDropDown);
}

SetDropDownHeight(&m_CodeAgence, 5);