Question

i’m facing a problem, currently i’m having a update panel in my master page and in one of my child page i’m having a asp fileupload control.

My update Panel in master p[age:

    <form id="form1" runat="server">
      <asp:ScriptManager ID="ScriptManager1" runat="server">
     </asp:ScriptManager>

     <asp:updateprogress associatedupdatepanelid="UpdatePanel1"
        id="updateProgress" runat="server">
         <progresstemplate>
            <div id="processMessage" style=" background-image:url('../../Styles/ajax-loader3.gif'); width:100px; height:100px; background-repeat:no-repeat; background-position:center;">

               </div>
        </progresstemplate>
    </asp:updateprogress> 

    <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
     <ContentTemplate>
..
    </ContentTemplate>
 </asp:UpdatePanel>
</form>

My Child page which needs a fileupload:

<div id="Annoucments" class="ContentDIV">
            <h2 class="Tabheader">Annoucments</h2>
            <p class="tabdescription">Here you will be able to upload announcements and pictures to be displayed in the login page, below is the current announcement click on update to save the changes that you have made.</p>

            <table width = "100%">

            <tr>
            <td class="Tablabel">Annoucment title:</td> <td class="tableInput" align="left"><asp:TextBox ID="Announcement_TB" runat="server" CssClass="textboxTabs"></asp:TextBox></td>
            <td class="Tablabel">Picture/Poster:</td> <td class="tableInput" align="left"><asp:FileUpload ID="Announcement_PIC" runat="server"  CssClass="textboxTabsFiles"/></td>
            </tr>

            <tr>
            <td class="Tablabel">Description:</td> <td class="tableInput" align="left"><asp:TextBox ID="Announcement_Desc" CssClass="textboxTabs" runat="server" Rows="3" TextMode="MultiLine"></asp:TextBox></td>
            </tr>

            <tr><td colspan="4" style="height:10px" id ="BLANK">
                <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
                </td></tr>

            <tr>
            <td colspan="2" align="right"><input type="button" id="Announcement_Update" runat="server" value="Update" class="TabButton" onserverclick="ANNOUNCEMENT_UPDATE_Click" style=" font-size:smaller"/></td><td colspan="2">&nbsp;&nbsp;<input type="button" ID="ANNOUNCEMENT_Cancel" runat="server" value="Cancel" class="TabButton" style=" font-size:smaller"/></td>  
            </tr>

            </table>

        </div>

*When i click the button Announcement_Update backend codes will be triggered to get my filename, the file name returned will always be “” found out while debugging.*

Answer 1

Put this code in child page, to pass PostBackTrigger for file upload.

protected void Page_Load(object sender, EventArgs e)
{
    UpdatePanel updatePanel = Page.Master.FindControl("UpdatePanel1") as UpdatePanel;
    UpdatePanelControlTrigger trigger  = new PostBackTrigger();
    trigger.ControlID = Announcement_Update.UniqueID;
    updatePanel.Triggers.Add(trigger);
}

enjoy coding 🙂