How to call the SQL commands asynchronously in ADO.NET
version 2.0

Answer Posted / kiran

This is the sample code which tells asynchronous access

<%@ 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();

// Starting the asynchronous processing
ASyncResult = Command.BeginExecuteReader();

// This loop with keep the main thread waiting
until the
// asynchronous process is finished
while (!ASyncResult.IsCompleted)
{
// Sleeping current thread for 10 milliseconds
System.Threading.Thread.Sleep(10);
}

// Retrieving result from the asynchronous process
OrdersReader = Command.EndExecuteReader
(ASyncResult);

// Displaying result on the screen
gvOrders.DataSource = OrdersReader;
gvOrders.DataBind();

// Closing connection
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>
<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>
</div>
</form>
</body>
</html>

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