Calculate GridView Running Total and Grand Total using C# in ASP.Net

Hi MohanbabuV,

I have created sample that full fill your requirement.

HTML

<div>
    <asp:GridView ID="gvProducts" runat="server" AutoGenerateColumns="false" OnRowDataBound="OnDataBound"
        ShowFooter="true">
        <Columns>
            <asp:BoundField DataField="Id" HeaderText="Id" />
            <asp:BoundField DataField="ProductName" HeaderText="Name" />
            <asp:BoundField DataField="Price" HeaderText="Price" />
            <asp:BoundField DataField="Unit" HeaderText="Unit" />
            <asp:TemplateField HeaderText="Total">
                <ItemTemplate>
                    <asp:Label ID="lblTotal" runat="server" />
                </ItemTemplate>
                <FooterTemplate>
                    <b>Grand Total:&nbsp;</b>
                    <asp:Label ID="lblGrandTotal" runat="server" />
                </FooterTemplate>
            </asp:TemplateField>
        </Columns>
    </asp:GridView>
</div>

Code

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[] 
        { 
            new DataColumn("Id", typeof(int)),
            new DataColumn("ProductName", typeof(string)),
            new DataColumn("Price",typeof(int)),
            new DataColumn("Unit",typeof(int)) 
        });
        dt.Rows.Add(1, "Aniseed Syrup", 10, 10);
        dt.Rows.Add(2, "Genen Shouyu", 15, 10);
        dt.Rows.Add(3, "Alice Mutton", 39, 10);
        dt.Rows.Add(4, "Teatime Biscuits", 12, 10);
        gvProducts.DataSource = dt;
        gvProducts.DataBind();
    }
}

int grandTotal = 0;
protected void OnDataBound(object sender, GridViewRowEventArgs e)
{
    if (e.Row.RowType == DataControlRowType.DataRow)
    {
        int price = int.Parse(e.Row.Cells[2].Text.Trim());
        int unit = int.Parse(e.Row.Cells[3].Text.Trim());
        Label total = e.Row.FindControl("lblTotal") as Label;
        total.Text = (price * unit).ToString();
        grandTotal += int.Parse(total.Text);
    }
    if (e.Row.RowType == DataControlRowType.Footer)
    {
        (e.Row.FindControl("lblGrandTotal") as Label).Text = grandTotal.ToString();
    }
}

Screenshot