所属分类 : Threading

Pools的实例

代码如下:

'-----------------------------------------------------------------------
'  This file is part of the Microsoft .NET Framework SDK Code Samples.
'
'  Copyright (C) Microsoft Corporation.  All rights reserved.
'
'This source code is intended only as a supplement to Microsoft
'Development Tools and/or on-line documentation.  See these other
'materials for detailed information regarding Microsoft code samples.
'
'THIS CODE AND INFORMATION ARE PROVIDED AS IS WITHOUT WARRANTY OF ANY
'KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
'IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
'PARTICULAR PURPOSE.
'=====================================================================
'  File:      AsyncMethod.vb
'
'  Summary:   Demonstrates thread pool usage
'
'=====================================================================

Option Explicit On
Option Strict On

Imports System
Imports System.Threading

Class App
    Public Shared Sub Main()
        Console.WriteLine("Main thread: Queuing an asynchronous operation.")
        Dim asyncOpIsDone As New AutoResetEvent(False)
        ThreadPool.QueueUserWorkItem(New WaitCallback(AddressOf MyAsyncOperation), asyncOpIsDone)
       
        Console.WriteLine("Main thread: Performing other operations.")
        ' ...
        Console.WriteLine("Main thread: Waiting for asynchronous operation to complete.")
        asyncOpIsDone.WaitOne()
    End Sub 'Main
   
   
   
    ' The callback method's signature MUST match that of a System.Threading.WaitCallback
    ' delegate (it takes an Object parameter and returns void)
    Shared Sub MyAsyncOperation(state As Object)
        Console.WriteLine("WorkItem thread: Performing asynchronous operation.")
        ' ...
        Thread.Sleep(5000) ' Sleep for 5 seconds to simulate doing work
        ' Signal that the async operation is now complete.
        CType(state, AutoResetEvent).Set()
    End Sub 'MyAsyncOperation
End Class 'App