Passing an object using Add event handler

I have a form were there a number of textboxes which are created on a form dynamically, the number of which varies according to initial parameters.

Due to the nature of data that the user has to input the text must be formatted to a set format on the 'textbox.leave' event

the attached code works perfectly for this textbox as there is no requirement for information from the textbox that raised the event. Is there some way to use a method like the 'Directcast()' method to obtain properties from the textbox which triggered the event?

Thanks,
Thomas

'' This code in in the form.load eventArg after the code that creates the synamic textboxes

        For Each ctl As Control In Me.Controls
            If TypeOf ctl Is TextBox Then
                AddHandler ctl.Leave, AddressOf tbleave
            End If
        Next

    End Sub

    Sub tbleave()
        MessageBox.Show("The user has left this textbox")
    End Sub

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