<%@ 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 OrdersCommand As SqlCommand = New SqlCommand()
        Dim CustCommand As SqlCommand = New SqlCommand()
        Dim OrdersReader As SqlDataReader
        Dim CustReader As SqlDataReader
        Dim OrdersASyncResult As IAsyncResult
        Dim CustAsyncResult As IAsyncResult

        Dim WHandles(1) As System.Threading.WaitHandle
        Dim OrdersWHandle As System.Threading.WaitHandle
        Dim CustWHandle As System.Threading.WaitHandle

        DBCon = New SqlConnection()
        DBCon.ConnectionString = _            
          ConfigurationManager.ConnectionStrings("DSN_NorthWind").ConnectionString

        CustCommand.CommandText = _
           "SELECT * FROM Customers WHERE CompanyName = 'Alfreds Futterkiste'"

        CustCommand.CommandType = CommandType.Text
        CustCommand.Connection = DBCon

        ' Selecting all orders for a specific customer 
        OrdersCommand.CommandText = _
                "SELECT Customers.CompanyName, Customers.ContactName, " & _
                "Orders.OrderID, Orders.OrderDate, " & _
                "Orders.RequiredDate, Orders.ShippedDate " & _
                "FROM Orders, Customers " & _
                "WHERE Orders.CustomerID = Customers.CustomerID " & _
                "AND Customers.CompanyName = 'Alfreds Futterkiste' " & _
                "ORDER BY Customers.CompanyName, Customers.ContactName"

        OrdersCommand.CommandType = CommandType.Text
        OrdersCommand.Connection = DBCon

        DBCon.Open()

        ' Retrieving customer information asynchronously
        CustAsyncResult = CustCommand.BeginExecuteReader()

        ' Retrieving orders list asynchronously
        OrdersASyncResult = OrdersCommand.BeginExecuteReader()

        CustWHandle = CustAsyncResult.AsyncWaitHandle
        OrdersWHandle = OrdersASyncResult.AsyncWaitHandle

        ' Filling Wait Handles array with the two wait handles we
        ' are going to use in this code
        WHandles(0) = CustWHandle
        WHandles(1) = OrdersWHandle

        System.Threading.WaitHandle.WaitAll(WHandles)

        CustReader = CustCommand.EndExecuteReader(CustAsyncResult)

        OrdersReader = OrdersCommand.EndExecuteReader(OrdersASyncResult)

        gvCustomers.DataSource = CustReader
        gvCustomers.DataBind()

        gvOrders.DataSource = OrdersReader
        gvOrders.DataBind()

        DBCon.Close()
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Wait All Approach</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <asp:GridView ID="gvCustomers" Width="100%" runat="server"></asp:GridView>
    <br /><br />
    <asp:GridView ID="gvOrders" Width="100%" AutoGenerateColumns="False"         
     runat="server">
       <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>
