How to listen variable property changes with external program

Question

I'm having a problem with my program that at its core uses a class variable to connect, control and extract information from CAD/CAM software called PowerShape.

What I'm trying to do is listen to this class variable to detect changes in its properties which happen if you do something inside Powershape. These would include the active window or model changing inside Powershape. The class variable is updating when changes are made, but I can't figure out how to detect it.

When class variable is declared it connects to Powershape and then you can access its properties:

Dim powershapeRoot As New PSAutomation(Delcam.ProductInterface.InstanceReuse.UseExistingInstance)
Dim PSmodelname = PowershapeRoot.activemodel.name

Now I would like to listen to the variable property "PowershapeRoot.activemodel.name" and see if it changes

How to do this?

Answer 1

To detect changes in the properties, you could use the INotifyPropertyChanged Interface.

You will find here the documentation from the MSDN.

In the setter of your property, you will need to include the code to raise the event. You can find an example below in VB.NET :

Public Class Demo Implements INotifyPropertyChanged

    Private nameValue As String = String.Empty

    Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged

    Private Sub NotifyPropertyChanged(ByVal info As String)
        RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(info))
    End Sub

    Public Property name() As String
        Get
            Return Me.nameValue
    End Get

    'Raise the event in the setter
    Set(ByVal value As String)
        If Not (value = nameValue) Then
            Me.nameValue = value
            NotifyPropertyChanged("name")
        End If
    End Set
    End Property
End Class