符合中小企业对网站设计、功能常规化式的企业展示型网站建设
本套餐主要针对企业品牌型网站、中高端设计、前端互动体验...
商城网站建设因基本功能的需求不同费用上面也有很大的差别...
手机微信网站开发、微信官网、微信商城网站...
vb.net中如何结束一个线程
成都创新互联主营新蔡网站建设的网络公司,主营网站建设方案,重庆APP开发,新蔡h5微信小程序开发搭建,新蔡网站营销推广欢迎新蔡等地区企业咨询
一般而言,如果您想终止一个线程,您可以使用System.Threading.Thread类的Abort方法. 例如:
Dim worker As ThreadStart = New ThreadStart(AddressOf workerthreadmethod)
Dim t As Thread = New Thread(worker)
t.Start()
MessageBox.Show("Wait for a while for the thread to start.")
MessageBox.Show(t.ThreadState.ToString())
t.Abort()
MessageBox.Show(t.ThreadState.ToString())
t.Join()
MessageBox.Show(t.ThreadState.ToString())
当然,在调用Abort方法后,线程并不是立刻终止,要等线程的所有finally快中的代码完成后才会完全终止. 所以在主线程中可以用Join方法来同步,当线程还未完全终止时,t.Join()将处于等待,直到t线程完全结束后再继续执行后面的语句。
Abort方法是会导致线程跳出一个异常错误的,你需要在代码中捕获该异常。下面是一个比较完整的VB.NET线程例子:
Imports System
Imports System.Threading
Public Class MyTestApp
Public Shared Sub Main()
Dim t As New Thread(New ThreadStart(AddressOf MyThreadMethod))
'Start the thread
t.Start()
MsgBox("Are you ready to kill the thread?")
'Kill the child thread and this will cause the thread raise an exception
t.Abort()
' Wait for the thread to exit
t.Join()
MsgBox("The secondary thread has terminated.")
End Sub
Shared Sub MyThreadMethod()
Dim i As Integer
Try
Do While True
Thread.CurrentThread.Sleep(1000)
Console.WriteLine("This is the secondary thread running.")
Loop
Catch e As ThreadAbortException
MsgBox("This thread is going to be terminated by the Abort method in the Main function")
End Try
End Sub
End Class
Thread.Abort()方法用来永久销毁一个线程,而且将抛出ThreadAbortException异常。使终结的线程可以捕获到异常但是很难控制恢复,仅有的办法是调用Thread.ResetAbort()来取消刚才的调用,而且只有当这个异常是由于被调用线程引起的异常。因此,A线程可以正确的使用Thread.Abort()方法作用于B线程,但是B线程却不能调用Thread.ResetAbort()来取消Thread.Abort()操作。
这个没法做到。原因
1)当你将方法排入线程池队列后,此方法在有线程池线程变得可用时执行。
2)线程池中某个线程的可用与不可用,是由.net 后台决定,用户程序无法控制的
3)正如你观察到的:线程启动的时间不同,有快有慢,这恰恰说明线程池起作用了:线程池的调度试图让程序响应达到最佳。
Sub Main()
Dim thr As Thread
For Pi As Integer=0 To 4 //启用5线程
MulParams =Pi vbTab sFile vbTab dFile vbTab 1 vbTab DelN vbTab cr vbTab cg vbTab cb vbTab IndexI
GlobalParamas(pi)=MulParams .Split(vbTab)
thr=New Thread(AddressOf MyMulThreadCaller)
thr.Start() //启动多线程进程
Application.DoEvents
Next
End Sub
Public Class Form1
Public Class SquareClass '把多线程调用的函数封装到类中,通过类事件返回
Public Value As Double
Public Square As Double
Public Event ThreadComplete(ByVal Square As Double)
Public Sub CalcSquare()
Square = Value * Value
RaiseEvent ThreadComplete(Square)
End Sub
End Class
Dim WithEvents oSquare As SquareClass
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click '多线程返回值测试,当线程运行完成激发事件
oSquare = New SquareClass()
Dim t As New Threading.Thread(AddressOf oSquare.CalcSquare)
oSquare.Value = 30
t.Start()
End Sub
Sub SquareEventHandler(ByVal Square As Double) Handles oSquare.ThreadComplete '响应事件函数
MsgBox("The square is " Square)
End Sub
End Class