Calculate and save Column total in variable using C# and VB.Net in ASP.Net

Hi rajeesh,

Check this sample. now take its reference and correct your code.

Database

For this example I have used of Northwind database that you can download using the link given below.

Download Northwind Database

HTML

<asp:Button ID="btnPrice" Text="Get Price" runat="server" OnClick="OnPrice" /><br /><br />
<asp:Label ID="lblPrice" Text="" runat="server" />

Namespaces

C#

using System.Configuration;
using System.Data;
using System.Data.SqlClient;

VB.Net

Imports System.Configuration
Imports System.Data
Imports System.Data.SqlClient

Code

C#

protected void OnPrice(object sender, EventArgs e)
{
    DataTable dt = GetData("SELECT SUM(CONVERT(NUMERIC(18,2),ISNULL(Freight,0))) AS Price FROM Orders");
    decimal totalPrice = 0;
    totalPrice = Convert.ToDecimal(dt.Rows[0][0]);
    lblPrice.Text = Convert.ToString(totalPrice);
}

private DataTable GetData(string query)
{
    using (SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["constr"].ConnectionString))
    {
        using (SqlCommand cmd = new SqlCommand(query, con))
        {
            cmd.CommandType = CommandType.Text;
            using (SqlDataAdapter sda = new SqlDataAdapter())
            {
                sda.SelectCommand = cmd;
                DataTable dt = new DataTable();
                sda.Fill(dt);
                return dt;
            }
        }
    }
}

VB.Net

Protected Sub OnPrice(ByVal sender As Object, ByVal e As EventArgs)
    Dim dt As DataTable = GetData("SELECT SUM(CONVERT(NUMERIC(18,2),ISNULL(Freight,0))) AS Price FROM Orders")
    Dim totalPrice As Decimal = 0
    totalPrice = Convert.ToDecimal(dt.Rows(0)(0))
    lblPrice.Text = Convert.ToString(totalPrice)
End Sub

Private Function GetData(ByVal query As String) As DataTable
    Using con As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
        Using cmd As SqlCommand = New SqlCommand(query, con)
            cmd.CommandType = CommandType.Text
            Using sda As SqlDataAdapter = New SqlDataAdapter()
                sda.SelectCommand = cmd
                Dim dt As DataTable = New DataTable()
                sda.Fill(dt)
                Return dt
            End Using
        End Using
    End Using
End Function

Screenshot