Data Binding ASP.Net Tutorial

  1. Home
  2. ASP.Net Tutorial
  3. Data Binding
  4. Data binding by filling list and drop-down list controls with the results of direct ADO NET queries
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" 
    Inherits="Default" %>



    DataSource-based Binding


    
        
            

Browse Customers


            
            
                 
                    
                
                 
                    
                         
                                
                    
                                            OnClick="CountriesButton_Click" />
                
            

            
                            OnClick="CustomersButton_Click" />
       
   



File: Default.aspx.cs
using System;
using System.Data;
using System.Data.SqlClient;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Default : System.Web.UI.Page
{
    protected void CountriesButton_Click(object sender, EventArgs e)
    {
        if (CountryList.Items.Count > 1)
            return;
        string connString = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
        using (SqlConnection conn = new SqlConnection(connString))
        {
            string cmdText = "SELECT DISTINCT country FROM customers";
            SqlCommand cmd = new SqlCommand(cmdText, conn);
            cmd.Connection.Open();
            using (SqlDataReader reader = cmd.ExecuteReader())
            {
                CountryList.DataSource = reader;
                CountryList.DataTextField = "country";
                CountryList.DataBind();
            }
        }
    }
    protected void CustomersButton_Click(object sender, EventArgs e)
    {
        CustomerList.Items.Clear();
        string connString = ConfigurationManager.ConnectionStrings["NorthwindConnectionString"].ConnectionString;
        string cmdText1 = "SELECT CustomerID, CompanyName, Country FROM customers";
        string cmdText2 = "SELECT CustomerID, CompanyName, Country FROM customers WHERE country='{0}'";
        string cmdText = cmdText1;
        if (CountryList.SelectedIndex > 0)
            cmdText = String.Format(cmdText2, CountryList.SelectedValue);
        DataSet data = new DataSet();
        SqlDataAdapter adapter = new SqlDataAdapter(cmdText, connString);
        adapter.Fill(data);
        CustomerList.DataMember = "Table";
        CustomerList.DataTextField = "companyname";
        CustomerList.DataValueField = "customerid";
        CustomerList.DataSource = data;
        CustomerList.DataBind();
    }
}