I am unable to use FileUpload which is in Gridview in the UpdatePanel, have also used trigger, how can i solve this?

Question

I want to use UpdatePanel for my GridView, but the FileUpload in GridView doesn't work even if I added trigger... Because it cant find FileUpload Button, whats the solution?

<asp:TemplateField HeaderText="Upload Kundli">
  <ItemTemplate>
    <asp:FileUpload ID="FileUpload1" runat="server" /><br />
    <asp:Button ID="btnupload" runat="server" Text="Upload" OnClick="btnupload_Click" />
  </ItemTemplate>
  <ItemStyle HorizontalAlign="Center" />
  <HeaderStyle HorizontalAlign="Center" />
</asp:TemplateField>

</Columns>

</asp:GridView>

</ContentTemplate>
<Triggers>
  <asp:PostBackTrigger ControlID="btnupload" />
</Triggers>
</asp:UpdatePanel>

Answer 1

Here is a way I do it via code behind, its just dummy mockup to give you an idea:

ASPX Code:

<form id="form1" runat="server">
<asp:ScriptManager ID="ScriptManager1" runat="server">        
    </asp:ScriptManager>  

<asp:UpdatePanel runat="server">
<ContentTemplate>
    <asp:Label runat="server" ID="Label1" Text=""></asp:Label>    
<asp:GridView runat="server" ID="GridView1" OnRowDataBound="GridView1_RowDataBound">
    <Columns>
    <asp:TemplateField HeaderText="Upload Kundli">
                                <ItemTemplate>
                                    <asp:FileUpload ID="FileUpload1" runat="server" /><br />
                                    <asp:Button ID="btnupload" runat="server" Text="Upload"       OnClick="btnupload_Click" />
                                </ItemTemplate>
                                 <ItemStyle HorizontalAlign="Center" />
                                <HeaderStyle HorizontalAlign="Center" />
                            </asp:TemplateField>

          </Columns>

    </asp:GridView>

    </ContentTemplate>

        </asp:UpdatePanel>
        </form>

Code Behind (ASPX.CS):

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                List<int> gridItems = new List<int>();
                gridItems.Add(1);
                gridItems.Add(2);
                GridView1.DataSource = gridItems;
                GridView1.DataBind();
            }
        }

        protected void GridView1_RowDataBound(Object sender, GridViewRowEventArgs e)
        {
            //May not need this if. So check depending on what and how you are binding.
            if (e.Row.RowType == DataControlRowType.DataRow)
            {
                Button UploadButon = (Button) e.Row.Cells[0].FindControl("btnupload");
                if(UploadButon != null)
                {
                    if (this.ScriptManager1 != null)
                    {
                        this.ScriptManager1.
                            RegisterAsyncPostBackControl(UploadButon);
                    }
                }

            }

        }
        protected void btnupload_Click(object sender, EventArgs e)
        {
            Label1.Text = Label1.Text + "a";
        }