Question

我想创建一个可以暂停和恢复的计时器对象。当前Timers.Timer类的问题在于，当您调用Stop()然后调用Start()时，它会重置间隔并在整个间隔过去后再次触发。

例如，如果我有timerA timerA.Interval = 5000

现在如果我做timerA.Start()然后3秒后我打电话给timerA.Stop()然后我想等2分钟。

在这2分钟之后，我想打电话给timerA.Start()，这应该在 2秒之后触发Elapsed事件（即恢复我2分钟前离开的地方）。但问题是Timers.Timer.Start()将在5秒后再次发射（从0开始，而不是从3秒开始）。

无论如何，我创建了一个继承自Timers.Timer的VB.NET类，所以如果上面的暂停逻辑与我的代码一致，请你告诉我们吗？

代码：

Imports System.Timers

Public Class TimerWithPause
Inherits Timers.Timer

Dim m_stopwatch As New Stopwatch
Dim m_interval As Integer 'original interval
Dim m_remainngtime As Integer 'to use when the Pause is requested
Dim m_state As TimerState = TimerState.Stopped

Public Sub New(Interval As Integer)
    m_interval = Interval
    MyBase.Interval = Interval
End Sub

Public Overloads Property Interval As Integer
    Get
        Return m_interval
    End Get
    Set(value As Integer)
        m_interval = value
        MyBase.Interval = m_interval
    End Set
End Property

ReadOnly Property CurrentState As TimerState
    Get
        Return m_state
    End Get
End Property

Public Overloads Sub Start(startSate As StartStatus)
    MyBase.Interval = m_interval
    Select Case startSate
        Case StartStatus.StartNew
            StartNew()
        Case StartStatus.ResumeTimer
            'if current state is paused then resume
            If m_state = TimerState.Paused Then
                m_state = TimerState.Running
                m_stopwatch.Start()
                If m_remainngtime > 0 Then
                    MyBase.Interval = m_remainngtime
                End If
                MyBase.Start()
            ElseIf m_state = TimerState.Stopped Then 'else if the timer is stopped then start new
                StartNew()
            End If
    End Select
End Sub

Public Overloads Sub [Stop](stopState As StopStatus)
    Select Case stopState
        Case StopStatus.StopTimer
            m_state = TimerState.Stopped
            m_stopwatch.Reset()
            MyBase.Stop()
        Case StopStatus.PauseTimer
            m_state = TimerState.Paused
            m_stopwatch.Stop()
            MyBase.Stop()
            m_remainngtime = m_interval - m_stopwatch.ElapsedMilliseconds
    End Select
End Sub

Private Sub TimerWithPause_Elapsed(sender As Object, e As ElapsedEventArgs) Handles Me.Elapsed
    StartNew() 'if the timer fires then it starts new cycle (because pauses happen in a middle of a running cycle)
End Sub

Private Sub StartNew()
    m_remainngtime = 0
    MyBase.Interval = m_interval
    m_state = TimerState.Running
    m_stopwatch.Restart()
    MyBase.Start()
End Sub

Enum StartStatus
    StartNew = 1
    ResumeTimer = 2
End Enum

Enum StopStatus
    PauseTimer = 1
    StopTimer = 3
End Enum

Enum TimerState
    Running = 1
    Stopped = 2
    Paused = 3
End Enum

End Class

我用这种方式：

Dim WithEvents tmr As New TimerWithPause(8000)
Private Sub RadButton10_Click(sender As Object, e As EventArgs) Handles RadButton10.Click
    Select Case tmr.CurrentState
        Case TimerWithPause.TimerState.Running
            tmr.Stop(TimerWithPause.StopStatus.PauseTimer)
        Case TimerWithPause.TimerState.Stopped
            tmr.Start(TimerWithPause.StartStatus.StartNew)
        Case TimerWithPause.TimerState.Paused
            tmr.Start(TimerWithPause.StartStatus.ResumeTimer)
    End Select
End Sub

提前谢谢你们

暂停定时器（Timers.Timer）VB.NET

0 个答案: