以前一直感觉多线程比较难懂，最近由于需要，没办法必须克服，这不看了几遍书，终于理解差不多了，先把最开始的一个实例弄上来吧。
Imports System.Threading
'看名字就知道，这个类干什么用的，多线程应用程序都要用这个类
Public Delegate Function BinaryOp(ByVal x As Integer,ByVal y As Integer) As Integer
Module Module1
Sub Main()
Console.WriteLine("***** Synch Delegate Review *****")
' Print out the ID of the executing thread.
Console.WriteLine("Main() invoked on thread {0}.",Thread.CurrentThread.ManagedThreadId)
' Invoke Add() in a synchronous manner.
Dim b As New BinaryOp(AddressOf Add)
' Could also write b.
Invoke(10,10);
注意区别 同步方式是invoke,已不是beginInvoke
Dim answer As Integer = b(10,10)
' These lines will not execute until
' the Add() method has completed.
Console.WriteLine("Doing more work in Main()!")
Console.WriteLine("10 + 10 is {0}.",answer)
Console.ReadLine()
End Sub
Private Function Add(ByVal x As Integer,ByVal y As Integer) As Integer
' Print out the ID of the executing thread.
Console.WriteLine("Add() invoked on thread {0}.",Thread.CurrentThread.ManagedThreadId)
' Pause to simulate a lengthy operation.
Thread.Sleep(5000)
Return x + y
End Function
End Module
不知道大家怎么理解这个同步和异步。反正这个不大好理解,我觉得主要就看是否有阻塞或者尽可能小的阻塞。特别是同步调用方式和同步调用线程的区别，特别是很多翻译过来的东西，最好还是看原文和实例。
---------------------------一以下异步调用代码----------------------------------------------------
Imports System.Threading
'看名字就知道，这个类干什么用的，多线程应用程序都要用这个类
Public Delegate Function BinaryOp(ByVal x As Integer,ByVal y As Integer) As Integer
Module Module1
Sub main()
Console.WriteLine("***** Async Delegate Invocation *****")
' Print out the ID of the executing thread.
Console.WriteLine("Main() invoked on thread {0}.",Thread.CurrentThread.ManagedThreadId)
Dim b As New BinaryOp(AddressOf Add)
Dim iftAR As IAsyncResult = b.BeginInvoke(10,10,Nothing,Nothing)
' This message will keep printing until
' the Add() method is finished.
Do While Not iftAR.IsCompleted
Console.WriteLine("Doing more work in Main()!")
Thread.Sleep(1000)
Loop
' Now we know the Add() method is complete.
Dim answer As Integer = b.EndInvoke(iftAR)
Console.WriteLine("10 + 10 is {0}.",answer)
Console.ReadLine()
End Sub
Private Function Add(ByVal x As Integer,ByVal y As Integer) As Integer
' Print out the ID of the executing thread.
Console.WriteLine("Add() invoked on thread {0}.",Thread.CurrentThread.ManagedThreadId)
' Pause to simulate a lengthy operation.
Thread.Sleep(5000)
Return x + y
End Function
End Module
