Add Default Item to ASP.Net DropDownList when it is bind from database

    <asp:DropDownList ID="DropDownList1" runat="server">
    </asp:DropDownList>

        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[2] { new DataColumn("Item"), new DataColumn("Id") });
        dt.Rows.Add("Shirt", "1");
        dt.Rows.Add("Pant", "2");
        DropDownList1.DataSource = dt;
        DropDownList1.DataTextField = "Item";
        DropDownList1.DataValueField = "Id";
        DropDownList1.DataBind();
        //Add default item
        DropDownList1.Items.Insert(0, new ListItem("Please select", "0"));