C#.NET ต้องการคำนวนหาทศนิยม 2 ตำแหน่ง ใน Gridview_RowdataBound

 if (e.Row.RowType == DataControlRowType.Footer)
            {
                Label Jan01 = (Label)e.Row.FindControl("lbtotalBudget_jan");
                Label Jan02 = (Label)e.Row.FindControl("lbtotalActual_jan");
                Label Jan03 = (Label)e.Row.FindControl("lbtotalIn_jan");
                Label Jan04 = (Label)e.Row.FindControl("lbtotalTurnover_jan");
                Label SumtotalJan = (Label)e.Row.FindControl("lbtotalPercent_jan");

                Jan01.Text = totalSum01_jan.ToString();
                Jan02.Text = totalSum02_jan.ToString();
                Jan03.Text = totalSum03_jan.ToString();
                Jan04.Text = totalSum04_jan.ToString();

                SumtotalJan.Text = (totalSum04_jan * (100) / totalSum02_jan).ToString();
}

<asp:TemplateField HeaderText="%">
<ItemTemplate>
<asp:Label ID="lbSumPercentJan" runat="server" Text='<%# DataBinder.Eval(Container, "DataItem.Percentjan","{0:N2}") %>'></asp:Label>
</ItemTemplate>
<FooterTemplate>
<asp:Label ID="lbtotalPercent_jan" runat="server" Text=""></asp:Label>
</FooterTemplate>
</asp:TemplateField>