如何拦截使用属性的类属性设置器

Question

我想统计一些特定属性的设置次数。 我能做到这样的：

Class Test 
    Private changeCounter As New Dictionary(Of String, Integer) 

    Private _myProp1 As String 
    Public Property MyProp1() As String 
     Get 
      Return _myProp1 
     End Get 
     Set(ByVal value As String) 
      _myProp1 = value 

      If Not changeCounter.ContainsKey("MyProp1") Then 
       changeCounter.Add("MyProp1", 0) 
      End If 

      changeCounter("MyProp1") += 1 
     End Set 
    End Property 

    Private _myProp2 As String 
    Public Property MyProp2() As String 
     Get 
      Return _myProp2 
     End Get 
     Set(ByVal value As String) 
      _myProp2 = value 

      If Not changeCounter.ContainsKey("MyProp2") Then 
       changeCounter.Add("MyProp2", 0) 
      End If 

      changeCounter("MyProp2") += 1 
     End Set 
    End Property 

    Public Sub Print() 
     For Each pair In changeCounter 
      Console.WriteLine("{0} : {1}", pair.Key, pair.Value) 
     Next 
    End Sub 
End Class 

用法：

Dim t As New Test 
t.MyProp1 = "value 1" 
t.MyProp1 = "value 2" 
t.MyProp2 = "value 3" 
t.Print() 

'Output 
MyProp1 : 2 
MyProp2 : 1 

我的属性想知道如果同样的可以用一些自定义来实现，以使代码更清洁。例如：

Class Test 
    Private changeCounter As New Dictionary(Of String, Integer) 

    <SomeCustomAttribute("MyProp1", ...)> 
    Public Property MyProp1() As String 

    <SomeCustomAttribute("MyProp2", ...)> 
    Public Property MyProp2() As String 

    Public Sub Print() 
     For Each pair In changeCounter 
      Console.WriteLine("{0} : {1}", pair.Key, pair.Value) 
     Next 
    End Sub 
End Class 

Answer 1

为什么不只是使用内部私人功能？

Class Test 
    Private changeCounter As New Dictionary(Of String, Integer) 

    Private _myProp1 As String 
    Public Property MyProp1() As String 
     Get 
      Return _myProp1 
     End Get 
     Set(ByVal value As String) 
      _myProp1 = value 
      CountChange("MyProp1")    
     End Set 
    End Property 

    Private _myProp2 As String 
    Public Property MyProp2() As String 
     Get 
      Return _myProp2 
     End Get 
     Set(ByVal value As String) 
      _myProp2 = value 
      CountChange("MyProp2")    
     End Set 
    End Property 

Public Sub Print() 
    For Each pair In changeCounter 
     Console.WriteLine("{0} : {1}", pair.Key, pair.Value) 
    Next 
End Sub 

Private Sub CountChange(ByVal PropName As String) 
    If Not changeCounter.ContainsKey(PropName) Then 
     changeCounter.Add(PropName, 0) 
    End If 
    changeCounter("MyProp1") += 1 
End Sub 

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