Thread.Join方法的用途：在继续执行标准的 COM 和 SendMessage 消息泵处理期间，阻塞调用线程，直到某个线程终止为止。

实例：

Imports System.Threading

Public Class IsThreadPool

    Shared Sub Main()
        Dim autoEvent As New AutoResetEvent(False)

        Dim regularThread As New Thread(AddressOf ThreadMethod)
        regularThread.Start()
        ThreadPool.QueueUserWorkItem(AddressOf WorkMethod, autoEvent)

        ' 等待前台线程结束.
        regularThread.Join()

        ' 等待后台线程结束.
        autoEvent.WaitOne()
    End Sub

    Shared Sub ThreadMethod()
        Console.WriteLine("ThreadOne, executing ThreadMethod, " & _
            "is from the thread pool? {0}", _
            Thread.CurrentThread.IsThreadPoolThread)
    End Sub

    Shared Sub WorkMethod(stateInfo As Object)
        Console.WriteLine("ThreadTwo, executing WorkMethod, " & _
            "is from the thread pool? {0}", _
            Thread.CurrentThread.IsThreadPoolThread)

        ' 标识线程已经完成

             DirectCast(stateInfo, AutoResetEvent).Set()
    End Sub

End Class