<asp:GridView ID="GridView2" runat="server" AutoGenerateColumns="False" Height="153px"
            Width="300px">
            <Columns>
                <asp:BoundField DataField="serial" HeaderText="No" />
                <asp:TemplateField HeaderText="Upload Items">
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text="Path"></asp:Label>
                        <asp:FileUpload ID="FileUpload1" runat="server" />
                        <asp:Label ID="Label2" runat="server" Text="Description"></asp:Label>
                        <asp:TextBox ID="txtdes" runat="server"></asp:TextBox><br>                      
                       
                        <asp:RadioButton ID="chkk1" Text="Lock" runat="server" GroupName="j" />
                        <asp:Image ID="Image2" runat="server" ImageUrl="~/images/locked.gif" />
                        
                        <asp:RadioButton ID="chkk2" Text="UnLock" runat="server" Checked="true" GroupName="j" />
                        <asp:Image ID="Image1" runat="server" ImageUrl="~/images/unlocked.gif" />
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>

 <asp:DropDownList ID="drpupload" runat="server" CssClass="select"  
        AutoPostBack="True" 
         onselectedindexchanged="drpupload_SelectedIndexChanged1" Visible="False" >
   
        <asp:ListItem Value="0" Selected="True">Multiple File Upload</asp:ListItem>
        <asp:ListItem Value="1">Upload 2 files</asp:ListItem>
        <asp:ListItem Value="2">Upload 3 files</asp:ListItem>
        <asp:ListItem Value="3">Upload 4 files</asp:ListItem>
        <asp:ListItem Value="4">Upload 5 files</asp:ListItem>
        <asp:ListItem Value="5">Upload 6 files</asp:ListItem>
        <asp:ListItem Value="6">Upload 7 files</asp:ListItem>
        <asp:ListItem Value="7">Upload 8 files</asp:ListItem>
        <asp:ListItem Value="8">Upload 9 files</asp:ListItem>
        <asp:ListItem Value="9">Upload 10 files</asp:ListItem>
        <asp:ListItem Value="10">Upload 11 files</asp:ListItem>
        <asp:ListItem Value="11">Upload 12 files</asp:ListItem>
        <asp:ListItem Value="12">Upload 13 files</asp:ListItem>
        <asp:ListItem Value="13">Upload 14 files</asp:ListItem>
        <asp:ListItem Value="14">Upload 15 files</asp:ListItem>
    </asp:DropDownList>



protected void drpupload_SelectedIndexChanged1(object sender, EventArgs e)
    {
       
        if (drpupload.SelectedItem.Text == "Multiple File Upload")
        {
            GridView2.Visible = false;

        }

        else
        {
            Panel1.Visible = false;
            GridView2.Visible = true;
            dt.Columns.Add("serial");
            int n;
            n = Convert.ToInt32(drpupload.SelectedItem.Value);
            for (int i = 0; i <= n; i++)
            {
                dt.Rows.Add();
                dt.Rows[i]["serial"] = i + 1;

            }
            GridView2.DataSource = dt;
            GridView2.DataBind();
        }
    }