vb.net问题
Me.Dispose和Me.Close和End有什么区别?哪个资源释放的更彻底?
追问：Environment.Exit(0)中的退出代码"0"有什么用吗?都有哪些值?
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答案：执行 dispose 后,由.net 的GC垃圾回收器周期性地回收资源, me.close 方法的基类会调用 dispose 方法end 是从vb中继承下来的语句,直接指示退出程序.程序的资源将被释放,程序并未希望结束时,不适合使用该方法.若要强行退出应用程序,在.net中可以使用Environment.Exit(0)
下面是 system.windows.forms.form 类对 close 和 dispose 的封装:
'------- Close
Public Sub Close()
If MyBase.GetState(&H40000) Then
Throw New InvalidOperationException(SR.GetString("ClosingWhileCreatingHandle", New Object() { "Close" }))
End If
If MyBase.IsHandleCreated Then
Me.closeReason = CloseReason.UserClosing
MyBase.SendMessage(&H10, 0, 0)
Else
MyBase.Dispose
End If
End Sub
'------- Dispose
Protected Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
Me.CalledOnLoad = False
Me.CalledMakeVisible = False
Me.CalledCreateControl = False
If MyBase.Properties.ContainsObject(Form.PropAcceptButton) Then
MyBase.Properties.SetObject(Form.PropAcceptButton, Nothing)
End If
If MyBase.Properties.ContainsObject(Form.PropCancelButton) Then
MyBase.Properties.SetObject(Form.PropCancelButton, Nothing)
End If
If MyBase.Properties.ContainsObject(Form.PropDefaultButton) Then
MyBase.Properties.SetObject(Form.PropDefaultButton, Nothing)
End If
If MyBase.Properties.ContainsObject(Form.PropActiveMdiChild) Then
MyBase.Properties.SetObject(Form.PropActiveMdiChild, Nothing)
End If
If (Not Me.MdiWindowListStrip Is Nothing) Then
Me.MdiWindowListStrip.Dispose
Me.MdiWindowListStrip = Nothing
End If
If (Not Me.MdiControlStrip Is Nothing) Then
Me.MdiControlStrip.Dispose
Me.MdiControlStrip = Nothing
End If
If (Not Me.MainMenuStrip Is Nothing) Then
Me.MainMenuStrip = Nothing
End If
Dim form As Form = DirectCast(MyBase.Properties.GetObject(Form.PropOwner), Form)
If (Not form Is Nothing) Then
form.RemoveOwnedForm(Me)
MyBase.Properties.SetObject(Form.PropOwner, Nothing)
End If
Dim formArray As Form() = DirectCast(MyBase.Properties.GetObject(Form.PropOwnedForms), Form())
Dim i As Integer = (MyBase.Properties.GetInteger(Form.PropOwnedFormsCount) - 1)
Do While (i >= 0)
If (Not formArray(i) Is Nothing) Then
formArray(i).Dispose
End If
i -= 1
Loop
If (Not Me.smallIcon Is Nothing) Then
Me.smallIcon.Dispose
Me.smallIcon = Nothing
End If
Me.ResetSecurityTip(False)
MyBase.Dispose(disposing)
Me.ctlClient = Nothing
Dim menu As MainMenu = Me.Menu
If ((Not menu Is Nothing) AndAlso (menu.ownerForm Is Me)) Then
menu.Dispose
MyBase.Properties.SetObject(Form.PropMainMenu, Nothing)
End If
If (Not MyBase.Properties.GetObject(Form.PropCurMenu) Is Nothing) Then
MyBase.Properties.SetObject(Form.PropCurMenu, Nothing)
End If
Me.MenuChanged(0, Nothing)
Dim menu2 As MainMenu = DirectCast(MyBase.Properties.GetObject(Form.PropDummyMenu), MainMenu)
If (Not menu2 Is Nothing) Then
menu2.Dispose
MyBase.Properties.SetObject(Form.PropDummyMenu, Nothing)
End If
Dim menu3 As MainMenu = DirectCast(MyBase.Properties.GetObject(Form.PropMergedMenu), MainMenu)
If (Not menu3 Is Nothing) Then
If ((menu3.ownerForm Is Me) OrElse (menu3.form Is Nothing)) Then
menu3.Dispose
End If
MyBase.Properties.SetObject(Form.PropMergedMenu, Nothing)
End If
Else
MyBase.Dispose(disposing)
End If
End Subme.dispose这个是最彻底 释放资源
Me.Close 这个是关闭
end 只是结束 一般用在程序的语句中 如结束语句
me.close 会调用窗口的close方法，在close方法中系统会自动dispose
所以close在某些情况下和dispose效果一样
end会使VB程序直接结束
以下摘自MSDN
End 语句可以放在过程中的任何位置，以强制整个应用程序停止运行。End 关闭通过 Open 语句打开的所有文件，并清除应用程序的所有变量。只要其他程序没有引用应用程序的对象并且应用程序的代码当前都未运行，该应用程序就会立即关闭。
