vb.net - 两个定时器同时独立运行

Question

首先，我只想对过去几周给予的所有帮助表示感谢。我学到了很多东西，我的程序每天为我节省了很多时间。

我想稍微扩展它并添加与第一个计时器并行运行的第二个计时器，但不受第一个计时器的任何形状或形式的影响。

我尝试在第一个循环中嵌套第二个循环，但第二个循环需要 3 秒才能完成(我使用 thread.sleep(3000))，所以我发现它卡住了第一个循环，直到第二个循环完成。我正在阅读有关系统线程 (System.Timers.Timer) 的内容，这似乎是我想要走的路线。

我写这个很快作为例子:

这假设我添加了一个 Windows 计时器控件作为 timer1

Option Strict On
Imports System
Imports System.Timers

Public Class form1

  Private Shared timer2 As System.Timers.Timer
  timer2 = New System.Timers.Timer
  AddHandler timer2.Elapsed, AddressOf OnTimedEvent

  Public Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
                           Handles Button1.Click
    timer1.Interval = 1000
    timer1.enabled = true
    timer2.Interval = 5000
    timer2.Enabled = True
  End sub

  Public Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) _
                         Handles Timer1.Tick
  'code for timer1 here
  End Sub

  Private Shared Sub OnTimedEvent(source As Object, e As ElapsedEventArgs)
    'code for timer2 here
  End Sub

End Class 

这甚至有意义吗？...而且由于 thread.sleep，我再次无法使用 timer1 来触发第二轮事件。 .我希望上面的代码让第二个线程进入休眠状态，而 windows.form.timer每 1000 毫秒继续滴答

Answer 1

Public Class Form1
    'a timer that fires periodically
    Dim WithEvents aTimer As New System.Threading.Timer(AddressOf TickTock, Nothing, 0, 500)
    'a stopwatch for each event
    Dim swEV1 As New Stopwatch
    Dim swEV2 As New Stopwatch
    'how long between executions
    Dim ev1Time As New TimeSpan(0, 0, 1)
    Dim ev2Time As New TimeSpan(0, 0, 5)

    'test
    Private Sub Button1_Click(sender As System.Object, _
                              e As System.EventArgs) Handles Button1.Click
        Button1.Enabled = False
        'start the test
        swEV1.Start()
        swEV2.Start()
    End Sub

    Dim ev1 As New Threading.Thread(AddressOf event1)
    Dim ev2 As New Threading.Thread(AddressOf event2)

    Private Sub TickTock(state As Object)
        If swEV1.IsRunning Then
            'check the elapsed time and run the thread when needed
            'only one thread per event is allowed to run
            If swEV1.Elapsed >= ev1Time Then
                If Not ev1.IsAlive Then
                    swEV1.Reset() 'reset the stopwatch
                    swEV1.Start()
                    ev1 = New Threading.Thread(AddressOf event1)
                    ev1.IsBackground = True
                    ev1.Start()
                End If
            End If

            If swEV2.Elapsed >= ev2Time Then
                If Not ev2.IsAlive Then
                    swEV2.Reset()
                    swEV2.Start()
                    ev2 = New Threading.Thread(AddressOf event2)
                    ev2.IsBackground = True
                    ev2.Start()
                End If
            End If

        End If
    End Sub

    Private Sub event1()
        Debug.WriteLine("EV1 " & DateTime.Now.ToString)
        Threading.Thread.Sleep(500) 'simulate work
    End Sub

    Private Sub event2()
        Debug.WriteLine("EV2 " & DateTime.Now.ToString)
        Threading.Thread.Sleep(3000) 'simulate work
    End Sub


End Class