You can check the following MSDN article
to see how to assign an even in code using VB.NET code. You can switch between the languages for the code snippets in the article from the drop down "Language" menu on the right side of the page. In general you can do the following:
AddHandler rb.Click, AddressOf Onb2Click
Private Sub Onb2Click(ByVal sender As Object, ByVal e As RoutedEventArgs)
I hope that helps.
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