Excel DNA VB.net中构造函数和类解构器的使用问题

Question

在这段代码中，我预计uTest1函数内的vCallLevel变量将等于1，退出后将重置为0。但是，当从函数返回时，它会保留其值，当再次调用uTest1函数时，vCallLevel值会再次增加1(析构函数中的MsgBox也不会执行(。这意味着在退出时不会调用Protected Overrides Sub Finalize((析构函数。但是，当我关闭Excel时，我会多次收到MsgBox消息。我做错了什么？

{  
Imports ExcelDna.Integration
Public Module Fun
Public vCallLevel As Double
Public Class tcLocal
Public Sub New()
vCallLevel = vCallLevel + 1
End Sub
Protected Overrides Sub Finalize()
vCallLevel = vCallLevel - 1
MsgBox(vCallLevel)
MyBase.Finalize()
End Sub
End Class
Public Function uTest1() As Double
Dim oLocal As New tcLocal
Return vCallLevel
End Function
End Module
}

我就是这样做的。无论如何都不起作用。。。

Imports ExcelDna.Integration
Public Module Fun
Public vCallLevel As Double
Public Class tcLocal
Implements IDisposable
#Region "IDisposable Support"
Private disposedValue As Boolean
Protected Overridable Sub Dispose(disposing As Boolean)
If Not disposedValue Then
If disposing Then
vCallLevel = vCallLevel - 1
MsgBox(vCallLevel)
End If
End If
disposedValue = True
End Sub
Public Sub Dispose() Implements IDisposable.Dispose
Dispose(True)
End Sub
Public Sub New()
vCallLevel = vCallLevel + 1
End Sub
#End Region
End Class
Public Function uTest1() As Double
Dim oLocal As New tcLocal
Return vCallLevel
End Function
End Module

事实上，我只需要在oLocal内部进行这些操作——在退出uTest功能时初始化和停用：

Public vCallLevel As Double
Public Class tcLocal
Public Sub New ()
vCallLevel = vCallLevel + 1
End Sub
Public Sub "Called on exit from uTest function" ()
vCallLevel = vCallLevel - 1               
End Sub
End Class
Public Function uTest1 () As Double
Dim oLocal As New tcLocal
Return vCallLevel
End Function

我正在尝试从VBA翻译我的代码，一个类中只有两个标准SUB。。。

Private Sub Class_Initialize()
CallLevel = CallLevel + 1      
End Sub
Private Sub Class_Terminate()
CallLevel = CallLevel - 1
End Sub

Answer 1

以下是IDisposable在VB.NET中的实现：

Public Class Fun
Implements IDisposable
#Region "IDisposable Support"
Private disposedValue As Boolean ' To detect redundant calls
' IDisposable
Protected Overridable Sub Dispose(disposing As Boolean)
If Not disposedValue Then
If disposing Then
' TODO: dispose managed state (managed objects).
End If
' TODO: free unmanaged resources (unmanaged objects) and override Finalize() below.
' TODO: set large fields to null.
End If
disposedValue = True
End Sub
' TODO: override Finalize() only if Dispose(disposing As Boolean) above has code to free unmanaged resources.
'Protected Overrides Sub Finalize()
'    ' Do not change this code.  Put cleanup code in Dispose(disposing As Boolean) above.
'    Dispose(False)
'    MyBase.Finalize()
'End Sub
' This code added by Visual Basic to correctly implement the disposable pattern.
Public Sub Dispose() Implements IDisposable.Dispose
' Do not change this code.  Put cleanup code in Dispose(disposing As Boolean) above.
Dispose(True)
' TODO: uncomment the following line if Finalize() is overridden above.
' GC.SuppressFinalize(Me)
End Sub
#End Region
End Class

---

Public Function uTest1() As Double
Using oLocal As New tcLocal
Return vCallLevel
End Using
End Function