Mega Code Archive

 
Categories / ASP.Net Tutorial / ADO Net Database
 

The Poll approach of working with asynchronous commands (VB)

<%@ Page Language="VB" %> <%@ Import Namespace="System.Data" %> <%@ Import Namespace="System.Data.SqlClient" %> <%@ Import Namespace="System.Configuration" %> <script runat="server">     Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)          Dim DBCon As SqlConnection         Dim Command As SqlCommand = New SqlCommand()         Dim OrdersReader As SqlDataReader         Dim ASyncResult As IAsyncResult         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 Not ASyncResult.IsCompleted             System.Threading.Thread.Sleep(10)         End While         OrdersReader = Command.EndExecuteReader(ASyncResult)         gvOrders.DataSource = OrdersReader         gvOrders.DataBind()         DBCon.Close()     End Sub </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>