Problem with Download and upload feature while in update panel.

[pratsadhu]

Hi,

I have an update panel with a dropdown list. On index change, values will be populated from databas. The dropdownlist and the table are placed in an update panel. Now, i have added another table with download and upload features. if i try to put these button in the update panel an error is raised saying:
" Response method has been modified or Server trace is enabled.
My requiremet needs the download feature to be visible only the selected index change. How do I avoid the error?'


Thanks

[Frinavale]

I'm not sure what you are trying to do...
You have a DropDownList and then when a user selects an item you Repopulate the DropDownList with something else?

Could you please post your code so that I can better understand what you're doing?

[pratsadhu]

Here I have a DropDownList ddlHoldingComp and a gridview gvTraining
On DropDownList SelectedIndexchange, the grid view will be updated and the upload download buttons will be visible.
Now if i put the upload download buttons in UpdatePanel, and try to download a file the Aspx page throws an error saying
"The Response has been changed or server trace has been enabled".

Following is my code.

  <asp:UpdatePanel ID="UpdatePanel1" runat="server">
          <contenttemplate>
                <table>
                <tr>
                    <td>
                       <asp:UpdatePanel ID="UpdatePanel9" runat="server">
                          <contenttemplate>
                                <table id="tblLookup" cellspacing="0" cellpadding="5" width="100%" border="0" runat="server">                  
                                    <tr>                      
                                        <td align="left" width="73%">
                                            <asp:DropDownList ID="ddlHoldingComp" runat="server" AutoPostBack="true" 
                                                Width="45%" OnSelectedIndexChanged="ddlHoldingComp_SelectedIndexChanged">
                                            </asp:DropDownList>
                                        </td>
                                    </tr>
 
                                </table>
                            </contenttemplate>
                      </asp:UpdatePanel>
                    </td>
                </tr>
                <tr>
                    <td>
                       <asp:UpdatePanel ID="UpdatePanel7" runat="server">
                          <contenttemplate>   
 
                            <table width="100%" border="0" cellpadding="0" cellspacing="5" visible="false">
                                <tr align="left" valign="top">
                                    <td>
                                        <asp:GridView ID="gvTraining" BorderColor="DarkGray" runat="server" Width="98%" CellPadding="5"
                                            HeaderStyle-CssClass="table-head3" AlternatingRowStyle-BackColor="#e1e1e1" HorizontalAlign="Left"
                                            AutoGenerateColumns="False" >
                                            <Columns>
                                                <asp:TemplateField HeaderText="Select">
                                                    <ItemTemplate>
                                                        <asp:RadioButton ID="rbtnSelect" runat="server" onClick="ShowHideControls(this)"></asp:RadioButton>
                                                    </ItemTemplate>
                                                    <HeaderStyle HorizontalAlign="center" BorderColor="DarkGray" />
                                                    <ItemStyle BorderColor="DarkGray" HorizontalAlign="Center" VerticalAlign="top">
                                                    </ItemStyle>
                                                </asp:TemplateField>
                                                <asp:BoundField DataField="Description" HeaderText="Trainings" HeaderStyle-HorizontalAlign="Center"
                                                    HtmlEncode="false">
                                                    <ItemStyle CssClass="fieldstext" BorderColor="DarkGray" HorizontalAlign="left" Width="90%">
                                                    </ItemStyle>
                                                </asp:BoundField>
                                            </Columns>
                                            <HeaderStyle CssClass="table-head3" BorderColor="DarkGray"></HeaderStyle>
                                            <AlternatingRowStyle BackColor="#E1E1E1"></AlternatingRowStyle>
                                        </asp:GridView>
                                    </td>
                                </tr>
                            </table>
 
                          </contenttemplate>
                       </asp:UpdatePanel>  
                    </td>
                 </tr>
                <tr>
                    <td>
                        <asp:UpdatePanel ID="UpdatePanel2" runat="server">
                            <contenttemplate>
                                <table border="0" width="90%" cellpadding="5" cellspacing="0" style="border-color: Gray;" id="tblUpload" runat="server" visible=false>
                                        <tr valign="middle">                                               
                                            <td width="31%" align="left" valign="top">
 
                                                <asp:LinkButton runat="server" SkinID="lbtnSkin" ID="ibtnDownload" Text="Text"
                                                    OnClick="ibtnDownload_Click"></asp:LinkButton>
 
                                            </td>
                                        </tr>
 
                                        <tr>
                                            <td colspan="2" valign="top">
                                                <asp:FileUpload ID="fileUpload" runat="server" Width="98%"></asp:FileUpload>
                                            </td>
                                            <td align="left">
 
                                                <asp:ImageButton ID="ibtnUpload" runat="server" BorderWidth="0" ImageUrl="~/Images/upload-but.gif"
                                                    OnClick="ibtnUpload_Click" OnClientClick="ValidateUpload()"></asp:ImageButton>                                                
                                            </td>
                                        </tr>
                                 </table> 
                            </contenttemplate>
                        </asp:UpdatePanel>
                    </td>
 
                 </tr>
                 </table>
          </contenttemplate>
       </asp:UpdatePanel>