Calculate ASP.Net GridView Row Total and display sum in Footer using C# and VB.Net

Hi makumbi,

Please refer below sample.

HTML

<asp:ScriptManager ID="ScriptManager1" runat="server">
</asp:ScriptManager>
<asp:Panel ID="Panel1" runat="server">
<asp:UpdatePanel ID="UpdatePanel2" runat="server">
    <ContentTemplate>
        <asp:GridView ID="Gvgridclient" runat="server" AutoGenerateColumns="False" ShowFooter="True">
            <Columns>
                <asp:BoundField DataField="ItemCode" HeaderText="ItemCode" />
                <asp:BoundField DataField="ItemDescription" HeaderText="ItemDescription" />
                <asp:BoundField DataField="ItemSize" HeaderText="ItemSize" />
                <asp:TemplateField HeaderText="Quantity">
                    <EditItemTemplate>
                        <asp:TextBox ID="Quantity" runat="server" Text='<%# Bind("Quantity") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="Fqty" runat="server" Width="46px"></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:TextBox ID="txtQuantity" runat="server" Text='<%# Eval("Quantity") %>' Width="46px"
                            OnTextChanged="quantity_TextChanged" AutoPostBack="true"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="OrderPrice" HeaderText="OrderPrice" />
                <asp:TemplateField HeaderText="SalePrice">
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox3" runat="server" Text='<%# Bind("SalePrice") %>'></asp:TextBox>
                    </EditItemTemplate>
                    <ItemTemplate>
                        <asp:Label ID="Label1" runat="server" Text='<%# Bind("SalePrice") %>' Visible="False"></asp:Label>
                        <asp:TextBox ID="txtSalePrice" runat="server" Height="16px" Text='<%# Eval("SalePrice") %>' Width="85px"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:TemplateField HeaderText="SubTotal">
                    <EditItemTemplate>
                        <asp:TextBox ID="TextBox2" runat="server"></asp:TextBox>
                    </EditItemTemplate>
                    <FooterTemplate>
                        <asp:TextBox ID="txtFsubtotal" runat="server" Width="46px"></asp:TextBox>
                    </FooterTemplate>
                    <ItemTemplate>
                        <asp:Label ID="lblsubtotal" runat="server" Text='<%# Bind("SubTotal") %>'></asp:Label>
                        <asp:TextBox ID="txtsubtotal" runat="server" Height="16px" Text='<%# Eval("SubTotal") %>' Width="75px"></asp:TextBox>
                    </ItemTemplate>
                </asp:TemplateField>
                <asp:BoundField DataField="Prno" HeaderText="Prno" />
                <asp:BoundField DataField="Names" HeaderText="Names" />
                <asp:BoundField DataField="Date" HeaderText="Date" />
                <asp:TemplateField HeaderText="DelSingle">
                    <ItemTemplate>
                        <asp:LinkButton ID="lnkRemove" runat="server" Text="Delete"></asp:LinkButton>
                    </ItemTemplate>
                </asp:TemplateField>
            </Columns>
        </asp:GridView>
    </ContentTemplate>
</asp:UpdatePanel>
</asp:Panel>

Namespaces

C#

using System.Data;

VB.Net

Imports System.Data

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        DataTable dt = new DataTable();
        dt.Columns.AddRange(new DataColumn[11] {
                new DataColumn("ItemCode"),
                new DataColumn("ItemDescription"),
                new DataColumn("ItemSize"),
                new DataColumn("Quantity"),
                new DataColumn("OrderPrice"),
                new DataColumn("SalePrice"),
                new DataColumn("SubTotal"),
                new DataColumn("Prno"),
                new DataColumn("Names"),
                new DataColumn("Date"),
                new DataColumn("DelSingle")});
        dt.Rows.Add("012", "Item 1", "5cm", "40", "10", "450", "4510", "04215", "Excel", "10/04/2022");
        dt.Rows.Add("013", "Item 2", "6cm", "70", "80", "820", "5361", "0258", "Word", "04/05/2022");
        dt.Rows.Add("014", "Item 3", "4cm", "210", "59", "890", "8468", "85642", "Text", "18/06/2022");
        dt.Rows.Add("015", "Item 4", "9cm", "440", "70", "40", "8120", "47258", "Items", "20/07/2022");
        dt.Rows.Add("016", "Item 5", "7cm", "450", "80", "50", "9812", "69140", "Excel", "31/08/2022");
        Gvgridclient.DataSource = dt;
        Gvgridclient.DataBind();
        this.CalculateGrandTotal();
    }
}
protected void quantity_TextChanged(object sender, EventArgs e)
{
    double qt;
    double qcost;
    GridViewRow row = (sender as TextBox).NamingContainer as GridViewRow;
    int kk = row.RowIndex;
    qt = Convert.ToDouble(((TextBox)Gvgridclient.Rows[kk].FindControl("txtQuantity")).Text);
    qcost = Convert.ToDouble(((TextBox)Gvgridclient.Rows[kk].FindControl("txtSalePrice")).Text);
    ((TextBox)Gvgridclient.Rows[kk].FindControl("txtsubtotal")).Text = (qt * qcost).ToString();
    ((Label)Gvgridclient.Rows[kk].FindControl("lblsubtotal")).Text = (qt * qcost).ToString();
    this.CalculateGrandTotal();
}

private void CalculateGrandTotal()
{
    double total = 0;
    foreach (GridViewRow row in Gvgridclient.Rows)
    {
        string subtotal = ((Label)row.FindControl("lblsubtotal")).Text;
        total += !string.IsNullOrEmpty(subtotal) ? Convert.ToDouble(subtotal) : 0;
    }

    (Gvgridclient.FooterRow.FindControl("txtFsubtotal") as TextBox).Text = total.ToString();
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim dt As DataTable = New DataTable()
        dt.Columns.AddRange(New DataColumn(10) {
                            New DataColumn("ItemCode"),
                            New DataColumn("ItemDescription"),
                            New DataColumn("ItemSize"),
                            New DataColumn("Quantity"),
                            New DataColumn("OrderPrice"),
                            New DataColumn("SalePrice"),
                            New DataColumn("SubTotal"),
                            New DataColumn("Prno"),
                            New DataColumn("Names"),
                            New DataColumn("Date"),
                            New DataColumn("DelSingle")})
        dt.Rows.Add("012", "Item 1", "5cm", "40", "10", "450", "4510", "04215", "Excel", "10/04/2022")
        dt.Rows.Add("013", "Item 2", "6cm", "70", "80", "820", "5361", "0258", "Word", "04/05/2022")
        dt.Rows.Add("014", "Item 3", "4cm", "210", "59", "890", "8468", "85642", "Text", "18/06/2022")
        dt.Rows.Add("015", "Item 4", "9cm", "440", "70", "40", "8120", "47258", "Items", "20/07/2022")
        dt.Rows.Add("016", "Item 5", "7cm", "450", "80", "50", "9812", "69140", "Excel", "31/08/2022")
        Gvgridclient.DataSource = dt
        Gvgridclient.DataBind()
        Me.CalculateGrandTotal()
    End If
End Sub

Protected Sub quantity_TextChanged(ByVal sender As Object, ByVal e As EventArgs)
    Dim qt As Double
    Dim qcost As Double
    Dim row As GridViewRow = TryCast((TryCast(sender, TextBox)).NamingContainer, GridViewRow)
    Dim kk As Integer = row.RowIndex
    qt = Convert.ToDouble((CType(Gvgridclient.Rows(kk).FindControl("txtQuantity"), TextBox)).Text)
    qcost = Convert.ToDouble((CType(Gvgridclient.Rows(kk).FindControl("txtSalePrice"), TextBox)).Text)
    CType(Gvgridclient.Rows(kk).FindControl("txtsubtotal"), TextBox).Text = (qt * qcost).ToString()
    CType(Gvgridclient.Rows(kk).FindControl("lblsubtotal"), Label).Text = (qt * qcost).ToString()
    Me.CalculateGrandTotal()
End Sub

Private Sub CalculateGrandTotal()
    Dim total As Double = 0
    For Each row As GridViewRow In Gvgridclient.Rows
        Dim subtotal As String = (CType(row.FindControl("lblsubtotal"), Label)).Text
        total += If(Not String.IsNullOrEmpty(subtotal), Convert.ToDouble(subtotal), 0)
    Next
    TryCast(Gvgridclient.FooterRow.FindControl("txtFsubtotal"), TextBox).Text = total.ToString()
End Sub

Screenshot