Application.Idle acting different

Question

我目前正致力于从中注销用户一定量的闲置时间。我宣布Application.Idle

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

然后，把它的形式加载事件

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 

而且计时器

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 

这样做的问题是每当空闲事件结束我我仍然收到一封通知，表示我已经再次锁定和/或应用程序已进入空闲事件。

control_acPasswords()是注销用户控制

而且这里是我释放内存

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 

如果我把一个MsgBox(ex.Message)上Timer_Tick事件例外，我不断收到

Object reference not set to an instance of an object

我的预期结果是每当表单进入空闲事件时，它会得到间隔或从My.Settings.LockOutTime这是一个分钟的时间，并存储为600001 minute或60 seconds并启动计时器的时间。现在在Timer_Tick上，然后logout用户如果间隔结束。

我是如何处理事件的？

Answer 1

Application.Idle事件触发多次。 Winforms每次从消息队列中检索所有消息并将其清空。问题在于，第二次和随后的时间都会触发，您正在启动一个已经启动的计时器。这没有任何作用，你必须重新设置它，以便在设定的时间间隔内再次开始滴答滴答。这很容易做到：

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

下一个问题是，可能是异常的原因，是你必须明确你的时候窗体关闭退订事件。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

除了汉斯回答：你似乎并没有停止定时器运行，当用户不再闲置。也就是说，当我闲置时计时器开始，但如果我回来，当计时器滴答时，我仍然会被锁定。

您需要确保在用户再次变为活动状态时停止计时器。