The Poll approach of working with asynchronous commands (C#) : IAsyncResult « ADO.net Database « ASP.NET Tutorial

<%@ Page Language="C#" %>
<%@ Import Namespace="System.Data" %>
<%@ Import Namespace="System.Data.SqlClient" %>
<%@ Import Namespace="System.Configuration" %>

<script runat="server">

    protected void Page_Load(object sender, EventArgs e)
    {
        SqlConnection DBCon;
        SqlCommand Command = new SqlCommand();
        SqlDataReader OrdersReader;
        IAsyncResult ASyncResult;

        DBCon = new SqlConnection();
        DBCon.ConnectionString =
          ConfigurationManager.ConnectionStrings["DSN_NorthWind"].ConnectionString;

        Command.CommandText = 
                "SELECT TOP 5 Customers.CompanyName, Customers.ContactName, " +
                " Orders.OrderID, Orders.OrderDate, " +
                " Orders.RequiredDate, Orders.ShippedDate " +
                " FROM Orders, Customers " +
                " WHERE Orders.CustomerID = Customers.CustomerID " +
                " ORDER BY Customers.CompanyName, Customers.ContactName "

        Command.CommandType = CommandType.Text;
        Command.Connection = DBCon;

        DBCon.Open();

        ASyncResult = Command.BeginExecuteReader();

        while (!ASyncResult.IsCompleted)
        {
            System.Threading.Thread.Sleep(10);
        }

        OrdersReader = Command.EndExecuteReader(ASyncResult);

        gvOrders.DataSource = OrdersReader;
        gvOrders.DataBind();

        DBCon.Close();
    }
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>The Poll Approach</title>
</head>
<body>
    <form id="form1" runat="server">
    <div><br />
    <asp:GridView ID="gvOrders" Runat="server" 
                    AutoGenerateColumns="False" Width="100%">
    <Columns>
        <asp:BoundField HeaderText="Company Name" 
            DataField="CompanyName"></asp:BoundField>
        <asp:BoundField HeaderText="Contact Name" 
            DataField="ContactName"></asp:BoundField>
        <asp:BoundField HeaderText="Order Date" 
            DataField="orderdate" DataFormatString="{0:d}"></asp:BoundField>
        <asp:BoundField HeaderText="Required Date" DataField="requireddate" 
            DataFormatString="{0:d}"></asp:BoundField>
        <asp:BoundField HeaderText="Shipped Date" DataField="shippeddate" 
            DataFormatString="{0:d}"></asp:BoundField>
    </Columns>
    </asp:GridView><br />
    </div>
    </form>
</body>
</html>

File: Web.config

<configuration>

  <connectionStrings>
        <add name="DSN_Northwind" 
             connectionString="Data Source=localhost\SQLEXPRESS;Initial Catalog=Northwind;Integrated Security=True"
             providerName="System.Data.SqlClient" />

    </connectionStrings>

</configuration>

18.47.IAsyncResult
	18.47.1.	The wait approach of handling a single asynchronous process (C#)
	18.47.2.	The wait approach of handling a single asynchronous process (VB)
	18.47.3.	Use of the WaitAny method of processing multiple asynchronous processes (C#)
	18.47.4.	Use of the WaitAny method of processing multiple asynchronous processes (VB)
	18.47.5.	The Poll approach of working with asynchronous commands (C#)
	18.47.6.	The Poll approach of working with asynchronous commands (VB)