How do I get the propertyname of WPF control?

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VB

WPF

Story:

I have a ListBox where I add custom objects, when the user clicks these custom objects in that ListBox some WPF Controls are generated in a stackpanel, these WPF Controls are properties of the custom objects. Below you may see the class.

Public Class VariableClass

    Public Property Content As String
    Public Property myNameLabel As New Label
    Public Property myNameTextBox As New ComboBox
    Public Property myTypeLabel As New Label
    Public Property myTypeTextBox As New ComboBox

    Public Overrides Function ToString() As String
        Return Content.ToString()
    End Function

End Class

I want to know what PropertyName the control the user types into has.

What I have tried:

Private Sub ValuePanel_PreviewKeyDown(sender As Object, e As KeyEventArgs) Handles ValuePanel.PreviewKeyDown
    Dim myElement As ComboBox = e.OriginalSource.TemplatedParent

    Dim myVar = GetValue(myElement).GetType().GetProperty("PropertyName")


End Sub

However myElement is not a DependencyObject and cannot be cast to one, I don't know how else to get the PropertyName or the VariableName.