How do I implement the OnPropertyChanged event in the generated code of my entity Model in partial classes that I add

Question

I have an Entity Data Model built using Devart's Entity Developer. It is a database first model and I set the template properties to implement INotifyPropertyChanged (and Changing) and to create separate partial classes for each entity in the model.

With the model built I am now looking at some auto generated code in the model for a property of an entity that looks like this:

Public Overridable Property Rc() As Global.System.Nullable(Of Integer)
        Get
            Return _Rc
        End Get
        Set
            If (Object.Equals(_Rc, value) = false) Then
              OnPropertyChanging("Rc")
              _Rc = value
              OnPropertyChanged("Rc")
            End If
        End Set
    End Property
    Private _Rc As Global.System.Nullable(Of Integer)

with further sections relating to INotifyPropertyChanged and Changing:

        #Region "INotifyPropertyChanging Members"

    Public Event PropertyChanging(sender As Object, e As PropertyChangingEventArgs) Implements INotifyPropertyChanging.PropertyChanging

    Protected Sub OnPropertyChanging(propertyName As String)
        RaiseEvent PropertyChanging(Me, New PropertyChangingEventArgs(propertyName))
    End Sub

    #End Region
    #Region "INotifyPropertyChanged Members"

    Public Event PropertyChanged(sender As Object, e As PropertyChangedEventArgs) Implements INotifyPropertyChanged.PropertyChanged

    Protected Sub OnPropertyChanged(propertyName As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(propertyName))
    End Sub

The model created a separate partial class for this entity and I assume that it should be in that partial class that I should put any code that I want that will react to the OnPropertyChanged. So for example with the property illustrated in the code snippet above (which would typically represent a year in the form of 2014) I would like to set the value of another of the entities properties to be 2014 + 5 ie 2019.

Could anyone explain to me how I should do this. I'd prefer vb if possible but can work with c#.

Thanks

Answer 1

For the benefit of others who may come to this at some point in the future.

I had an entity model built in its own project (so it was in effect a separate data layer) for a couple of solutions I am building. Each entity has its own separate partial class into which I add custom code. I knew that I would need to handle the PropertyChanged event in that partial class but I was constantly struggling to 'see' which property had fire the event.

It turns out that I had made a simple but fundamental mistake. Originally I had created the following method:

Private Sub OnPropertyChangedLogicImplementation(sender As Object, e As EventArgs) Handles Me.PropertyChanged
     Select Case e.PropertyName

    Case 
    End Select

End Sub

The reason it didn't work was that I had used EventArgs as opposed to PropertyChangedEventArgs which simply couldn't pick up the propertyname that I was expecting to be able to pick up.

Private Sub OnPropertyChangedLogicImplementation(sender As Object, e As PropertyChangedEventArgs) Handles Me.PropertyChanged
     Select Case e.PropertyName

    Case 
    End Select

End Sub

Oddly there is very little in the way of direct examples of how to do this that I could find and hence my original question. Hopefully this will save someone else wasting time looking for the painfully obvious (once of course you realise that it's painfully obvious!).