<%@ 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 WHIndex As Integer
        Dim WHandles(1) As Threading.WaitHandle
        Dim OrdersWHandle As Threading.WaitHandle
        Dim CustWHandle As 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

        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

        ' Opening the database connection
        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

        ' Looping 2 times because there are 2 wait handles 
        ' in the array
        For Index As Integer = 0 To 1
            ' We are only waiting for any of the two 
            ' asynchronous process to finish running
            WHIndex = Threading.WaitHandle.WaitAny(WHandles)

            ' The return value from the WaitAny method is
            ' the array index of the Wait Handle that just 
            ' finsihed running
            Select Case WHIndex
                Case 0
                    CustReader = CustCommand.EndExecuteReader(CustAsyncResult)

                    gvCustomers.DataSource = CustReader
                    gvCustomers.DataBind()                    
                Case 1
                    OrdersReader = _
                       OrdersCommand.EndExecuteReader(OrdersASyncResult)

                    gvOrders.DataSource = OrdersReader
                    gvOrders.DataBind()

            End Select
        Next

        ' Closing connection
        DBCon.Close()
    End Sub
</script>

<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>The Wait Any 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>
