Question

Greetins,

I am programmer from some time only, I have certain doubts in fundamentals, could you please clarify on the following:
Case 1:

Public Class BillItems
        Implements INotifyPropertyChanged
        Public Event PropertyChanged As PropertyChangedEventHandler Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
        Private Sub NotifyPropertyChanged(ByVal info As String)
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
        End Sub

        Private _BillIdValue As String


        Property BillId As String
            Get
                Return _BillIdValue
            End Get
            Set(ByVal value As String)
                If Not _BillIdValue = value Then
                    _BillIdValue = value
                End If
            End Set
        End Property
End Class

Case 2:

Public Class BillItems
        Implements INotifyPropertyChanged
        Public Event PropertyChanged As PropertyChangedEventHandler Implements System.ComponentModel.INotifyPropertyChanged.PropertyChanged
        Private Sub NotifyPropertyChanged(ByVal info As String)
            RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
        End Sub


        Property BillId As String
            Get
                Return BillId
            End Get
            Set(ByVal value As String)
                If Not BillId = value Then
                    BillId = value
                End If
            End Set
        End Property
End Case

Does case 1 and case 2 yield same result, I mean is a private value necessarily in there?, can we use property itself to use its own value in its Set and get statements?

Thank you.

Answer 1

I can’t imagine that Case 2 is going to run without causing a stack-overflow exception. You are essentially making an infinite loop that is going to constantly call itself.

Case 1 would be the right way to do it.

If you are using .Net 4 you could just do this (without the further Get/Set code):

Property BillId As String

This will generate the private member variable (_BillId) for you.

Edit:

You could try this to raise the event:

Property BillId As String
    Get
        Return _BillIdValue
    End Get
    Set(ByVal value As String)
        If Not _BillIdValue = value Then
            _BillIdValue = value
            NotifyPropertyChanged("BillId")
        End If
    End Set
End Property