Question

It seems like overkill to set the value of a nullable type and implement iNotifyPropertyChanged. Is there a better way of doing this?

        Private _WorkPhone As Long?
    Public Property [WorkPhone]() As Long?
        Get
            Return _WorkPhone
        End Get
        Set(ByVal value As Long?)
            If value.HasValue = False Then
                If _WorkPhone.HasValue = True Then
                    MyBase.RaisePropertyChanging("WorkPhone")
                    _WorkPhone = Nothing
                    MyBase.MarkDirty()
                    MyBase.RaisePropertyChanged("WorkPhone")
                End If
            Else
                If _WorkPhone.HasValue Then
                    If _WorkPhone.Value <> value.Value Then
                        MyBase.RaisePropertyChanging("WorkPhone")
                        _WorkPhone = value
                        MyBase.MarkDirty()
                        MyBase.RaisePropertyChanged("WorkPhone")
                    End If
                Else
                    MyBase.RaisePropertyChanging("WorkPhone")
                    _WorkPhone = value
                    MyBase.MarkDirty()
                End If
                MyBase.RaisePropertyChanged("WorkPhone")
            End If
        End Set
    End Property

I tried using simple code, but my breakpoint on MyBase.RaisePropertyChanging(“WorkPhone”) is never hit, and the value never changes.

    If _WorkPhone <> value Then
    MyBase.RaisePropertyChanging("WorkPhone")
    _WorkPhone = value
    MyBase.MarkDirty()
    MyBase.RaisePropertyChanged("WorkPhone")
End If

Answer 1

There is no need for all the complicated logic. If x and y are both nullables with the same underlying type then x equals y if and only if

1. x.HasValue is true
2. y.HasValue is true
3. x.Value equals y.Value

or

1. x.HasValue is false
2. y.HasValue is false

In neither of these cases would we want to raise a property changed notification and thus a simple test for non-equality will suffice. Thus:

Private _WorkPhone As Long?
    Public Property [WorkPhone]() As Long?
        Get
            Return _WorkPhone
        End Get
        Set(ByVal value As Long?)
            If Not _workPhone.Equals(value)
                MyBase.RaisePropertyChanging("WorkPhone")
                _WorkPhone = value
                MyBase.MarkDirty()
                MyBase.RaisePropertyChanged("WorkPhone")
            EndIf
        End Set
    End Property

Note that we ned to use Not Nullable(Of T).Equals instead of <> as the latter evaluates to Nothing if one if its operands is Nothing.