Application.Idle acting different

Question

我目前正致力於從中註銷用戶一定量的閒置時間。我宣佈Application.Idle

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

然後，把它的形式加載事件

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 

而且計時器

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 

這樣做的問題是每當空閒事件結束我我仍然收到一封通知，表示我已經再次鎖定和/或應用程序已進入空閒事件。

control_acPasswords()是註銷用戶控制

而且這裏是我釋放內存

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 

如果我把一個MsgBox(ex.Message)上Timer_Tick事件例外，我不斷收到

Object reference not set to an instance of an object

我的預期結果是每當表單進入空閒事件時，它會得到間隔或從My.Settings.LockOutTime這是一個分鐘的時間，並存儲爲600001 minute或60 seconds並啓動計時器的時間。現在在Timer_Tick上，然後logout用戶如果間隔結束。

我是如何處理事件的？

Answer 1

Application.Idle事件觸發多次。 Winforms每次從消息隊列中檢索所有消息並將其清空。問題在於，第二次和隨後的時間都會觸發，您正在啓動一個已經啓動的計時器。這沒有任何作用，你必須重新設置它，以便在設定的時間間隔內再次開始滴答滴答。這很容易做到：

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

下一個問題是，可能是異常的原因，是你必須明確你的時候窗體關閉退訂事件。它不是自動的，Application.Idle是一個靜態事件。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

除了漢斯回答：你似乎並沒有停止定時器運行，當用戶不再閒置。也就是說，當我閒置時計時器開始，但如果我回來，當計時器滴答時，我仍然會被鎖定。

您需要確保在用戶再次變爲活動狀態時停止計時器。