CODEWITHSUNDEEP
c#asp.net.netfile-uploadasp.net-ajax
Akshay Raut
Akshay Raut

Reputation: 413

Unable to upload photo asynchronously with FileUpload control using UpdatePanel

In my ASP.NET Web forms application, I am adding a feature to upload files but I don't want to do a full postback. So to make it asynchronous I thought of using UpdatePanel. This UpdatePanel contains a FileUpload control and a button to upload the selected photo. When I was debuggin my code to detect if file is actually selected or not, I found FileUpload's HasFile property to be false.

It works when I remove UpdatePanel but I don't understand why.

To help you understand, here is the code:

ASPX markups:

<asp:UpdatePanel ID="UPProf" runat="server">
<ContentTemplate>
<asp:FileUpload ID="FUDP" runat="server" />
<asp:Button ID="BUDP" runat="server" OnClick="BUDP_Click" Text="Upload your photo" />
</ContentTemplate>
<Triggers>
<asp:AsyncPostBackTrigger ControlID="BUDP" EventName="Click" />
</Triggers>
</asp:UpdatePanel>

Here's its CS code:

protected void BUDP_Click(object sender, EventArgs e)
{
    try
    {
        if (FUDP.HasFile)  //  code doesn't pass this if condition
        {
            FUDP.SaveAs("D:/Pictures/" + count + ".jpeg");  //it doesn't work since there is no file here
        }
        else
        {
           //Set some message for user
        }
    }
    catch (Exception ex)
    {
        //log the error
    }
}

Upvotes: 0

Views: 1169

Answers (1)

Win
Win

Reputation: 62260

Upload requires full page request. This is a limitation of the XmlHttpRequest component used in all AJAX frameworks for asynchronous calls to the application.

Remove the UpdatePanel or make BUDP button to perform postbacks.

<asp:UpdatePanel ID="UPProf" runat="server">
   <ContentTemplate>
      <asp:FileUpload ID="FUDP" runat="server" />
      <asp:Button ID="BUDP" runat="server" OnClick="BUDP_Click" 
          Text="Upload your photo" />
   </ContentTemplate>
   <Triggers>
      <asp:PostBackTrigger ControlID="BUDP" />
   </Triggers>
</asp:UpdatePanel>

Upvotes: 1

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