Question

I have used file upload control of asp.net but I am getting empty string while saving.my code-

<asp:FileUpload ID="fuProductLogo" runat="server" CssClass="file paddBottom5px"  />

.cs code is-

if (fuProductLogo.PostedFile != null && fuProductLogo.PostedFile.ContentLength > 0)
                {
...
}

but the .PstedFile and .CountLength is coming zero but the same code is working fine in another page.Please help.

Answer 1

If the FileUpload is in an UpdatePanel it will be cleared on each ajax-postback. You can use multiple UpdatePanels around the FileUpload control and keep the FileUpload out of them. Also make sure that the button that triggers the actual upload does a real postback, not an asyncpostback. Do this by adding the button to the PostbackTrigger of it’s UpdatePanel or by taking it out of the UpdatePanel.

<asp:FileUpload ID="FileUpload1" runat="server" />
<asp:UpdatePanel ID="UpdatePanel2" runat="server">
    <ContentTemplate>
        <asp:TextBox ID="TextBox2" runat="server" />
        <asp:Button ID="Submit" runat="server" Text="Submit" />
    </ContentTemplate>
    <Triggers>
        <asp:PostBackTrigger ControlID="Submit" />
    </Triggers>
</asp:UpdatePanel>  

You can also use an AsyncFileUpload control from the Asp.net Ajax Toolkit, it works inside an UpdatePanel but it is a little harder to get this to work.