Fileupload is not passing the file to Code Behind

Question

I am doing some tests to Upload any file and save it in a physical folder, but even with the file loaded on the screen, it is not passing in ID/value:

Example:

Follows codes:

aspx:

  <div style="font-family: Arial">
                            <asp:FileUpload ID="FileUpload1" runat="server" />
                            <asp:Button ID="Button1" runat="server" Text="Upload"
                                OnClick="Button1_Click" />
                            <br />
                            <br />
                            <asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
                                OnRowCommand="GridView1_RowCommand" BackColor="White"
                                BorderColor="#CC9966" BorderStyle="None"
                                BorderWidth="1px" CellPadding="4">
                                <Columns>
                                    <asp:TemplateField HeaderText="File" ShowHeader="False">
                                        <ItemTemplate>
                                            <asp:LinkButton ID="LinkButton1" runat="server"
                                                CausesValidation="False"
                                                CommandArgument='<%# Eval("File") %>'
                                                CommandName="Download" Text='<%# Eval("File") %>'>
                                            </asp:LinkButton>
                                        </ItemTemplate>
                                    </asp:TemplateField>
                                    <asp:BoundField DataField="Size" HeaderText="Size in Bytes" />
                                    <asp:BoundField DataField="Type" HeaderText="File Type" />
                                </Columns>
                                <FooterStyle BackColor="#FFFFCC" ForeColor="#330099" />
                                <HeaderStyle BackColor="#990000" Font-Bold="True"
                                    ForeColor="#FFFFCC" />
                                <PagerStyle BackColor="#FFFFCC" ForeColor="#330099"
                                    HorizontalAlign="Center" />
                                <RowStyle BackColor="White" ForeColor="#330099" />
                                <SelectedRowStyle BackColor="#FFCC66" Font-Bold="True"
                                    ForeColor="#663399" />
                                <SortedAscendingCellStyle BackColor="#FEFCEB" />
                                <SortedAscendingHeaderStyle BackColor="#AF0101" />
                                <SortedDescendingCellStyle BackColor="#F6F0C0" />
                                <SortedDescendingHeaderStyle BackColor="#7E0000" />
                            </asp:GridView>
                        </div>

aspx.Cs

  protected void Button1_Click(object sender, EventArgs e)
    {
        if (FileUpload1.HasFile)
        {
            string fileName = FileUpload1.FileName;
            FileUpload1.PostedFile
                .SaveAs(Server.MapPath("~/Downloads/") + fileName);
        }

        DataTable dt = new DataTable();
        dt.Columns.Add("File");
        dt.Columns.Add("Size");
        dt.Columns.Add("Type");

        foreach (string strfile in Directory.GetFiles(Server.MapPath("~/Downloads")))
        {
            FileInfo fi = new FileInfo(strfile);
            dt.Rows.Add(fi.Name, fi.Length.ToString(),
                GetFileTypeByExtension(fi.Extension));
        }

        GridView1.DataSource = dt;
        GridView1.DataBind();
    }

    private string GetFileTypeByExtension(string fileExtension)
    {
        switch (fileExtension.ToLower())
        {
            case ".docx":
            case ".doc":
                return "Microsoft Word Document";
            case ".xlsx":
            case ".xls":
                return "Microsoft Excel Document";
            case ".txt":
                return "Text Document";
            case ".jpg":
            case ".png":
                return "Image";
            default:
                return "Unknown";
        }
    }


    protected void GridView1_RowCommand(object sender,
     GridViewCommandEventArgs e)
    {
        Response.Clear();
        Response.ContentType = "application/octet-stream";
        Response.AppendHeader("Content-Disposition", "filename="
            + e.CommandArgument);
        Response.TransmitFile(Server.MapPath("~/Data/")
            + e.CommandArgument);
        Response.End();
    }
}

Answer 1

Researching a little, it seems to be a problem of Asp itself.. you need to add a Rigger to your Updatepanel in order to trigger an event at the click of the button:

<Triggers>
   <asp:PostBackTrigger ControlID="Upload" />
</Triggers>

Also add this line to your Page_load method:

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

An example of a Fileupload inside an Updatepanel:

    <asp:UpdatePanel ID="UpdatePanel1" UpdateMode="Always" runat="server">
        <ContentTemplate>
            <asp:FileUpload ID="FileUpload1" runat="server" />
            <asp:Button ID="UploadButton" runat="server" Text="Upload Selected File" OnClick="UploadButton_Click" />
            <asp:Label ID="UploadDetails" runat="server" Text=""></asp:Label>
        </ContentTemplate>
        <Triggers>
            <asp:PostBackTrigger ControlID="btnUpload" />
        </Triggers>
    </asp:UpdatePanel>