Calculate values and divide with third column in ASP.Net GridView using C# and VB.Net

Refer the sample code.

HTML

<asp:GridView ID="GridView1" runat="server" AutoGenerateColumns="False"
    Style="font-family: Calibri; font-size: medium">
    <Columns>
        <asp:TemplateField HeaderText="Functional Currency" HeaderStyle-BackColor="Khaki">
            <ItemTemplate>
                <asp:Label ID="FunctionalCurrency" runat="server" 
                    Text='<%# Bind("FunctionalCurrency") %>' Width="300"></asp:Label>
            </ItemTemplate>
            <HeaderStyle BackColor="Khaki"></HeaderStyle>
        </asp:TemplateField>
        <asp:TemplateField HeaderText="Current year"
            ItemStyle-Width="150" HeaderStyle-BackColor="Khaki">
            <ItemTemplate>
                <asp:TextBox ID="CurrentYear" runat="server" BorderStyle="None" Height="30px"
                    AutoPostBack="True" OnTextChanged="CurrentYear_TextChanged"></asp:TextBox>
            </ItemTemplate>
            <HeaderStyle BackColor="Khaki"></HeaderStyle>
            <ItemStyle Width="150px" />
        </asp:TemplateField>
    </Columns>
</asp:GridView>

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        System.Data.DataTable dt = new System.Data.DataTable();
        dt.Columns.Add("FunctionalCurrency");
        dt.Rows.Add("Gross Profit / Gross");
        dt.Rows.Add("Depreciation/Amortization");
        dt.Rows.Add("Operating Income (EBIT)");
        dt.Rows.Add("Total Interest Expense");
        dt.Rows.Add("Net Income");
        dt.Rows.Add("Cash Flow from Operations");
        dt.Rows.Add("Total");
        GridView1.DataSource = dt;
        GridView1.DataBind();
    }
}

protected void CurrentYear_TextChanged(object sender, EventArgs e)
{
    (GridView1.Rows[6].FindControl("CurrentYear") as TextBox).Text = this.CalculateTotal().ToString("N2");
}

private decimal CalculateTotal()
{
    decimal eBit;
    decimal.TryParse(((GridView1.Rows[2].FindControl("CurrentYear") as TextBox).Text), out eBit);
    decimal interestExpense;
    decimal.TryParse(((GridView1.Rows[3].FindControl("CurrentYear") as TextBox).Text), out interestExpense);
    decimal cashFlow;
    decimal.TryParse(((GridView1.Rows[5].FindControl("CurrentYear") as TextBox).Text), out cashFlow);
    if (cashFlow == 0)
    {
        cashFlow = 1;
    }
    return ((eBit + interestExpense) / cashFlow);
}

VB.Net

Protected Sub Page_Load(sender As Object, e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As Data.DataTable = New Data.DataTable()
        dt.Columns.Add("FunctionalCurrency")
        dt.Rows.Add("Gross Profit / Gross")
        dt.Rows.Add("Depreciation/Amortization")
        dt.Rows.Add("Operating Income (EBIT)")
        dt.Rows.Add("Total Interest Expense")
        dt.Rows.Add("Net Income")
        dt.Rows.Add("Cash Flow from Operations")
        dt.Rows.Add("Total")
        GridView1.DataSource = dt
        GridView1.DataBind()
    End If
End Sub

Protected Sub CurrentYear_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
    TryCast(GridView1.Rows(6).FindControl("CurrentYear"), TextBox).Text = Me.CalculateTotal().ToString("N2")
End Sub

Private Function CalculateTotal() As Decimal
    Dim eBit As Decimal
    Decimal.TryParse((TryCast(GridView1.Rows(2).FindControl("CurrentYear"), TextBox).Text), eBit)
    Dim interestExpense As Decimal
    Decimal.TryParse((TryCast(GridView1.Rows(3).FindControl("CurrentYear"), TextBox).Text), interestExpense)
    Dim cashFlow As Decimal
    Decimal.TryParse((TryCast(GridView1.Rows(5).FindControl("CurrentYear"), TextBox).Text), cashFlow)
    If cashFlow = 0 Then
        cashFlow = 1
    End If

    Return ((eBit + interestExpense) / cashFlow)
End Function

Screenshot