FileUpload.HasFile returns "False" for multiple files upload - ASP.net

Question

I am using ASP.net FileUpload control to upload multiple files in database.

<asp:UpdatePanel ID="UP_div_askQ" UpdateMode="Conditional" runat="server">
    <ContentTemplate>
        <asp:FileUpload ID="FUQuestionFiles" CssClass="form-control" AllowMultiple="true" runat="server" />
        <asp:Button ID="btnQSave" runat="server" CssClass="btn btn-success" Text="ASK QUESTION" OnClick="askQuestion" />
    </ContentTemplate>
    <Triggers>
        <asp:PostBackTrigger ControlID="btnQSave" />
    </Triggers>
</asp:UpdatePanel>

In code behind I am using HasFile to check if files are present or not.

log.Debug("there are file" + FUQuestionFiles.HasFile.ToString());

But HasFile returns false when more than one file is selected.

Note: In case where only one file is selected, it returns true.

Thanks for your help.

Answer 1

FileUpload has two different properties for checking if a/any file has uploaded:

FileUpload.HasFile:

Gets a value indicating whether the FileUpload control contains a file.

FileUpload.HasFiles:

Gets a value that indicates whether any files have been uploaded.

The best way to check if any files is uploaded is to check both HasFile and HasFiles together.

if(fileUpload1.HasFile || fileUpload1.HasFiles)
    // do some code!

Edit 1:

Have you tried to add line below in the Page_Load?

Page.Form.Attributes.Add("enctype", "multipart/form-data");

Edit 2:

Can you please explain what difference this line of code made?

From this Forms in HTML documents draft in W3C:

The content type "application/x-www-form-urlencoded" is inefficient for sending large quantities of binary data or text containing non-ASCII characters. The content type "multipart/form-data" should be used for submitting forms that contain files, non-ASCII data, and binary data.

If the form contains a file input the enctype attribute of the form should set to multipart/form-data.

I think you faced that problem because you put the FileUpload inside the UpdatePanel.