Question

我正在开发一个将在一定时间内注销用户的内容。我声明了Application.Idle

Private Sub Application_Idle(sender As Object, e As EventArgs)
    Timer.Interval = My.Settings.LockOutTime
    Timer.Start()
End Sub

然后，在表单加载事件

上调用它

Private Sub ctlManagePw_Load(sender As System.Object, e As System.EventArgs) Handles MyBase.Load
    AddHandler System.Windows.Forms.Application.Idle, AddressOf Application_Idle
End Sub

在计时器上

Private Sub Timer_Tick(sender As Object, e As EventArgs) Handles Timer.Tick
    Try
        If My.Settings.TrayIcon = 1 Then
            Me.ParentForm.Controls.Remove(Me)
            control_acPasswords()
            _Main.NotifyIcon.Visible = True
            _Main.NotifyIcon.ShowBalloonTip(1, "WinVault", "You've been locked out due to innactivity", ToolTipIcon.Info)
        End If
        'Stop
        Timer.Stop()
        Timer.Enabled = False
        'Flush memory
        FlushMemory()
    Catch ex As Exception
        'Error is trapped. LOL
        Dim err = ex.Message
    End Try
End Sub

这个问题是每当空闲事件结束时，我仍然会收到通知我已经再次锁定和/或应用程序已进入空闲事件。

control_acPasswords()是注销用户控件

这里是我释放记忆的地方

Declare Function SetProcessWorkingSetSize Lib "kernel32.dll" (ByVal process As IntPtr, ByVal minimumWorkingSetSize As Integer, ByVal maximumWorkingSetSize As Integer) As Integer
Public Sub FlushMemory()
    Try
        GC.Collect()
        GC.WaitForPendingFinalizers()
        If (Environment.OSVersion.Platform = PlatformID.Win32NT) Then
            SetProcessWorkingSetSize(Process.GetCurrentProcess().Handle, -1, -1)
            Dim myProcesses As Process() = Process.GetProcessesByName(Application.ProductName)
            Dim myProcess As Process
            For Each myProcess In myProcesses
                SetProcessWorkingSetSize(myProcess.Handle, -1, -1)
            Next myProcess
        End If
    Catch ex As Exception
        Dim err = ex.Message
    End Try
End Sub

如果我在Timer_Tick事件Exception上放置MsgBox(ex.Message)，我会继续

Object reference not set to an instance of an object

我的预期结果是，只要表单进入空闲事件，它就会得到My.Settings.LockOutTime的时间间隔或时间，这是一个分钟值并存储为60000 1 minute或{ {1}}并启动计时器。现在在Timer_Tick上，如果间隔结束，则60 seconds用户。

我处理事件有什么不对吗？

Answer 1

Application.Idle事件多次触发。 Winforms每次从消息队列中检索所有消息并清空它。问题是，它启动的第二次和随后的时间，你正在启动一个已经启动的计时器。这没有任何效果，您必须重置它，以便在编程的时间间隔内再次开始滴答。容易做到：

Private Sub Application_Idle(sender As Object, e As EventArgs)
    Timer.Interval = My.Settings.LockOutTime
    Timer.Stop()
    Timer.Start()
End Sub

下一个问题，可能是异常的原因，是您明确必须在表单关闭时取消订阅该事件。它不是自动的，Application.Idle是一个静态事件。使用FormClosed事件：

Protected Overrides Sub OnFormClosed(ByVal e As System.Windows.Forms.FormClosedEventArgs)
    Timer.Stop()
    RemoveHandler Application.Idle, AddressOf Application_Idle
    MyBase.OnFormClosed(e)
End Sub

Answer 2

除了Hans的回答：当用户不再闲置时，您似乎不会停止计时器运行。也就是说，当我空闲时计时器启动，但如果我回来，我会在计时器停止时被锁定。

当用户再次激活时，您需要确保停止计时器。

Application.Idle的行为不同

2 个答案: