ASP.Net file upload causing post back in update panel using triggers

Question

I have file upload control to upload the profile picture using update panel. I have used AsyncPostBackTrigger with update panel but still the page is causing full postback.

Below is my code inline.

<asp:UpdatePanel ID="pnlZerkerBasicProfile" runat="server">
<input type="file" id="myFile" name="myFile" class="file_input_hidden" onchange="javascript:FileUploadSubmit();" style="cursor: pointer;" />
<Triggers>
        <asp:AsyncPostBackTrigger ControlID="btnSaveProfilePicture" />
</Triggers>

Can anyone help?

Answer 1

change the trigger t a postback trigger since file upload is not available in Request.Form.AllKeys when async postback occurs via update panel. See this:

http://www.codeproject.com/Articles/16945/Simple-AJAX-File-Upload

Answer 2

This should work

<asp:ScriptManager ID="ScriptManager1" runat="server" EnablePartialRendering="true" />
    <div>
        <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="conditional">
            <Triggers>
                <asp:PostBackTrigger ControlID="Button1" />
            </Triggers>
            <ContentTemplate>
                 <asp:FileUpload ID="FileUpload1" runat="server" />
                 <asp:Button ID="Button1" runat="server"Text="Upload" OnClick="Button1_Click" />
            </ContentTemplate>
        </asp:UpdatePanel>
    </div>

Answer 3

This code should work. It will not cause postback.

<asp:UpdatePanel ID="pnlZerkerBasicProfile" runat="server">
   <ContentTemplate>
      <input type="file" id="myFile" name="myFile" class="file_input_hidden" 
             onchange="javascript:FileUploadSubmit();" style="cursor: pointer;" />
      <asp:Button ID="btnSaveProfilePicture" runat="server"Text="Upload" 
           OnClick="btnSaveProfilePicture_Click" />
   </ContentTemplate>
   <Triggers>
       <asp:PostBackTrigger ControlID="btnSaveProfilePicture"  />
   </Triggers> 
</asp:UpdatePanel>