Executing-Asynchronous-Database-Commands


            File: App_Code\AsyncDataLayer.cs
using System;
using System.Data;
using System.Data.SqlClient;
using System.Web.Configuration;
using System.Collections.Generic;
public class AsyncDataLayer
{
    private static readonly string _connectionString;
    private SqlCommand _cmdProducts;
    public IAsyncResult BeginGetProducts(AsyncCallback callback, Object state)
    {
        SqlConnection con = new SqlConnection(_connectionString);
        _cmdProducts = new SqlCommand("WAITFOR DELAY '0:0:01';SELECT Title,Director FROM Products", con);
        con.Open();
        return _cmdProducts.BeginExecuteReader(callback, state, CommandBehavior.CloseConnection);
    }
    public List EndGetProducts(IAsyncResult result)
    {        
        List results = new List();
        SqlDataReader reader = _cmdProducts.EndExecuteReader(result);
        while (reader.Read())
        {
            AsyncDataLayer.Product newProduct = new AsyncDataLayer.Product();
            newProduct.Title = (string)reader["Title"];
            newProduct.Director = (string)reader["Director"];
            results.Add(newProduct);
        }
        return results;
    }
    static AsyncDataLayer()
    {
        _connectionString = WebConfigurationManager.ConnectionStrings["Products"].ConnectionString
            + ";Asynchronous Processing=true";
    }
    public class Product
    {
        private string _title;
        private string _director;
        public string Title
        {
            get { return _title; }
            set { _title = value; }
        }
        public string Director
        {
            get { return _director; }
            set { _director = value; }
        }
    }
}
File: Web.config

  
             connectionString="Data Source=.\SQLEXPRESS;AttachDbFilename=|DataDirectory|MyDatabase.mdf;Integrated Security=True;User Instance=True" />
  

File: Default.aspx
<%@ Page Language="C#" Async="true" AsyncTimeout="1" Trace="true" %>
<%@ Import Namespace="System.Threading" %>
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

    private AsyncDataLayer dataLayer = new AsyncDataLayer();
    void Page_Load()
    {
        PageAsyncTask task = new PageAsyncTask(BeginGetData, EndGetData, TimeoutData, null, true);
        Page.RegisterAsyncTask(task);
        Page.ExecuteRegisteredAsyncTasks();
    }
    IAsyncResult BeginGetData(object sender, EventArgs e, AsyncCallback callback, object state)
    {
        Trace.Warn("BeginGetData: " + Thread.CurrentThread.GetHashCode());
        return dataLayer.BeginGetProducts(callback, state);
    }
    void EndGetData(IAsyncResult ar)
    {
        Trace.Warn("EndGetDate: " + Thread.CurrentThread.GetHashCode());
        grdProducts.DataSource = dataLayer.EndGetProducts(ar);
        grdProducts.DataBind();
    }
    void TimeoutData(IAsyncResult ar)
    {
        lblError.Text = "Could not retrieve data!";
    }



    Show Page AsyncTask


    
    
            id="lblError"
        Runat="server" />
            id="grdProducts"
        Runat="server" />
ADO Net Database ASP.Net Tutorial
