在Excel-DNA VB.net中使用Constructor和Class Deconstructor的问题

Question

在这段代码中，我预计 uTest1 函数中的 vCallLevel 变量将等于 1，并且在退出时它将重置为 0。但是，当从函数返回时，它保留了它的值，当再次调用uTest1函数时，vCallLevel值再次增加1（析构函数中的MsgBox也没有执行）。这意味着 Protected Overrides Sub Finalize () 析构函数不会在退出时调用。但是，当我关闭 Excel 时，我多次收到 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。无论如何都行不通...

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，我只需要这些动作发生在oLocal内部——退出uTest函数时的初始化和停用：

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，class 中只有 2 个标准 SUB ...

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

Answer 1

这是 VB.NET 中 IDisposable 的一个实现：

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

在Excel-DNA VB.net中使用Constructor和Class Deconstructor的问题

The problem of using the Constructor and Class Deconstructor in Excel-DNA VB.net

vb.net

class

excel-dna