ShowDialog Form property is empty - wpf

Question

I have two of the simplest forms, with a couple of Buttons and a TextBox. I click to open the second form (frmModal) using ShowDialog(), type some text into txtGreeting and press the Yes button. What should happen is that a MessageBox appears confirming the text that was entered into txtGreeting, but it is empty.
I understand that the Form's properties should be accessible until the form goes out of scope, but they disappear straight-away. I can't even read dialog.txtGreeting.Text.
Am I missing anything obvious please?
Public Class frmMain
Private Sub btnModal_Click(sender As Object, e As EventArgs) Handles btnModal.Click
Dim dialog As frmModal
dialog = New frmModal()
Dim result As DialogResult = frmModal.ShowDialog(Me)
If result = Windows.Forms.DialogResult.Yes Then
MessageBox.Show(dialog.Greeting)
End If
'dialog.Dispose()
End Sub
End Class
Public Class frmModal
Public Property Greeting As String
Get
Return txtGreeting.Text
End Get
Set(value As String)
End Set
End Property
Private Sub btnYes_Click(sender As Object, e As EventArgs) Handles btnYes.Click
MessageBox.Show(Greeting)
End Sub
End Class
The Yes button has it's DialogResult property set to Yes.
I've tried moving the dialog-declaration out of the click-event, using an (unnecessary) Dispose(), deliberately assigning the Greeting property in the Yes-click event..

Answer 1

You're effectively instantiating the form twice. By showing frmModal with ShowDialog and then asking for the Greeting value on the instance you created, named 'dialog'.
This should fix it.
Private Sub ModalTestButton_Click(sender As System.Object, e As System.EventArgs) Handles ModalTestButton.Click
Dim dialog As frmModal
dialog = New frmModal()
Dim result As DialogResult = dialog.ShowDialog(Me)
If result = Windows.Forms.DialogResult.Yes Then
MessageBox.Show(dialog.Greeting)
End If
End Sub