AdminPanel.aspx.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
using System.Data;

public partial class AdminPanel : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

        DataTable dt = new DataTable();
        String strConnString = System.Configuration.ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
        string strQuery = "select * from [Order] order by ID";
        SqlCommand cmd = new SqlCommand(strQuery);
        SqlConnection con = new SqlConnection(strConnString);
        SqlDataAdapter sda = new SqlDataAdapter();
        cmd.CommandType = CommandType.Text;
        cmd.Connection = con;
        try
        {
            con.Open();
            sda.SelectCommand = cmd;
            sda.Fill(dt);
            GridView1.DataSource = dt;
            GridView1.DataBind();
        }
        catch (Exception ex)
        {
            Response.Write(ex.Message);
        }
        finally
        {
            con.Close();
            sda.Dispose();
            con.Dispose();
        }
    }
}