Keep two-way binding when whole object has changed - vb.net

Question

I have a class:
Public Class TestClass
Implements INotifyPropertyChanged
Public Event PropertyChanged As PropertyChangedEventHandler Implements INotifyPropertyChanged.PropertyChanged
Public Sub OnNotifyChanged(ByVal pName As String)
RaiseEvent PropertyChanged(Me, New PropertyChangedEventArgs(pName))
End Sub
Private _One As Integer
Private _Two As Integer
Public Sub New(ByVal One As Integer, ByVal Two As Integer)
_One = One
_Two = Two
End Sub
Public Property One() As Integer
Get
Return _One
End Get
Set(ByVal value As Integer)
_One = value
OnNotifyChanged("One")
End Set
End Property
Public Property Two() As Integer
Get
Return _Two
End Get
Set(ByVal value As Integer)
_Two = value
OnNotifyChanged("Two")
End Set
End Property
End Class
I can create an instance and bind two TextBoxes to the object:
Dim MyObject As New TestClass(1, 2)
TextBoxOne.DataBindings.Add("Text", MyObject, "One")
TextBoxTwo.DataBindings.Add("Text", MyObject, "Two")
Now I can change the TextBoxes or the object:
MyObject.Two = 3
..the object and TextBoxes are updated in two ways.
Now I want to update the whole object:
MyObject = New TestClass(3, 4)
...but this doesn't update the TextBoxes.
What am I doing wrong?

Answer 1

Your text boxes hold a reference to the first instance of the object you've created.
Now you're creating a second instance, supposedly in order to replace the existing instance, but the text boxes are unaware of the change.
You needs to either:
Pass the new instance to the text boxes (directly, as you assigned the first instance, or indirectly by having some "Model" object that both boxes are bound to).
Update the existing instance instead of replacing it with a new one (you can simply assign values to the fields, or create some "AssignFrom (other)" method, etc.)
Get yourself some other - more orderly - way of notifiying the controls that their underlying data source has changed / should be changed.