Deleting file from folder

.aspx

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False">
            <Columns>
<asp:TemplateField>
                    <ItemTemplate>
                        <asp:Button ID="btndelete" runat="server"
                            CommandArgument='<%#Eval("File_names") + ";" +Eval("Paper_id")%>'
                            onclick="btndelete_Click" OnClientClick="return confirmDelete();"
                            style="background-color:rgb(9, 16, 198);color:White" Text="Delete"
                            Width="70px" />
                    </ItemTemplate>
                    <ItemStyle HorizontalAlign="Center" />
                </asp:TemplateField>
       </Columns>
</asp:GridView>


.cs

protected void btndelete_Click(object sender, EventArgs e)
    {
        Button bt = (Button)sender;
        string[] arg = bt.CommandArgument.ToString().Split(new char[] { ';' });
        string filepath = arg[0];
        System.IO.File.Delete(filepath);
        dl.paper_id = Convert.ToInt16(arg[1]);
        bl.delete_papers(dl);
        GridView1.DataSource = bl.all_papers();
        GridView1.DataBind();
    }