css - asp.net ModalPopupExtender : need to show scroll bar when overflow

Question

I display a gridview in a ModalPopupExtender. When the screen resolution is to small, the pop-up is to big to all be displayed on the page.

I just want to add scroll bar to the pop-up when this happen.

I know it's probably some CSS, but all I tried did not work.

here some base css

.modalTextBoxBackground
{
   background-color:Gray;
   filter:alpha(opacity=70);
   opacity:0.7;
}  
.modalTextBox
{
    border: 1px solid #FFFFFF;
    background-color: #0066CC;
    color: #00FFFF;

}

here some code from the aspx

<asp:Panel ID="OptionSelectionPanel" runat="server" CssClass="modalTextBox">
            <asp:UpdatePanel ID="OptionSelectionUpdatePanel" runat="server" UpdateMode="Conditional" >
            <Triggers>
                <asp:asyncPostBackTrigger ControlID="TemplateSelection" />
            </Triggers>
            <ContentTemplate>

            <table class="EditRow">
            <tr class="HeaderFooter">
            <td colspan="3" class="modalTextBoxTitle">
                Add options to Quote
            </td>
            </tr>
            <tr>
            <td>
                Manufacturer
            </td>
             <td>
                <asp:DropDownList ID="OptionManufacturerFilter" runat="server" 
                    DataSourceID="OptionManufacturerDataSource" DataTextField="Name" 
                    DataValueField="Code" AutoPostBack="True" >
                </asp:DropDownList>
            </td>
            </tr>

                            <tr>
            <td colspan="3">
                <asp:GridView ID="NewOptionSelection" 
                              runat="server" 
                              DataSourceID="AvailableOptions" 
                              DataKeyNames="Option_Id"
                              AllowPaging="True" 
                              AllowSorting="True" 
                              AutoGenerateColumns="false">
                <Columns>
                    <asp:BoundField DataField="category_Descr" HeaderText="Category" SortExpression="category_Descr,subcategory_Descr,code" />
                    <asp:BoundField DataField="subcategory_Descr" HeaderText="Sub-Category" SortExpression="subcategory_Descr,code" />
                    <asp:BoundField DataField="Manuf_Name" HeaderText="Manufacturer" SortExpression="Manuf_Name"/>
                </Columns></asp:GridView>
            </td>
            </tr>
            <tr class="HeaderFooter">
            <td colspan="3" class="Center">
                <asp:Button ID="OptionSelectionClose" runat="server" Text="Close" />

            </td>
            </tr>
            </table>
             </ContentTemplate>
            </asp:UpdatePanel>
        </asp:Panel>
       <asp:Button runat="server" ID="HiddenTargetControlForOptionSelectionModalPopup" style="display:none"/>    
        <cc1:ModalPopupExtender ID="OptionSelectionModalPopupExtender" runat="server" 
                                TargetControlID="HiddenTargetControlForOptionSelectionModalPopup"
                                PopupControlID="OptionSelectionPanel" 
                                BackgroundCssClass="modalTextBoxBackground" />

Answer 1

I just found this.

ModalPopupExtender does not show scroll bar

it was still not working, but it was because I use a masterpage, so I solved this using the ClientID.

(note: to center that inner asp:panel vertically, the only thing I found was to put it into a Table cell using style="vertical-align:middle". I also need set OptionSelectionTable's height using JavaScript because height="100%" fail with some browser.)

<script type="text/javascript">
  function pageLoad() {
      $get('<%= OptionSelectionPanel.ClientID %>').style.height = document.documentElement.clientHeight * 0.9 + "px";
      $get('<%= OptionSelectionTable.ClientID %>').style.height = document.documentElement.clientHeight * 0.9 + "px";
  }
    </script> 

I also had to add the HorizontalAlign="Center" and ScrollBars="Auto" and to the Panel ID="OptionSelectionPanel" (the modalpopup's PopupControlID).

I moved the CssClass="modalTextBox" to an inner asp:panel and restored the HorizontalAlign="Left".

 <asp:Panel ID="OptionSelectionPanel" runat="server" 
            HorizontalAlign="Center" ScrollBars="auto">
            <asp:UpdatePanel ID="OptionSelectionUpdatePanel" 
                             runat="server" 
                             UpdateMode="Conditional" >
            <Triggers>
                <asp:asyncPostBackTrigger ControlID="TemplateSelection" />
            </Triggers>
            <ContentTemplate>
                <table ID="OptionSelectionTable" 
                       runat="server" 
                       border="0" 
                       cellpadding="0" 
                       cellspacing="0">
                        <tr>
                        <td style="vertical-align:middle">    
                                <asp:Panel ID="OptionSelectionInnerPanel" 
                                           runat="server" 
                                           HorizontalAlign="Left" 
                                           CssClass="modalTextBox">
                                  <table class="EditRow">


                                              ......


                                  </table>
                               </asp:Panel>
                  </td></tr></table> 
             </ContentTemplate>
            </asp:UpdatePanel>
        </asp:Panel>