Visual Basic.NET - Desactivar lectura por teclado

Private Sub UnaTextBox_KeyUp(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles UnaTextBox.KeyUp

        UnaTextBox.Clear()

End Sub

Private Sub UnaTextBox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles UnaTextBox.KeyDown

        If e.KeyCode = ............

End Sub

Private Sub UnaTextBox_KeyDown(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles UnaTextBox.KeyDown

        MessageBox.Show(e.KeyCode.ToString)

        MessageBox.Show(CType(e.KeyCode, Integer))

End Sub

Private Sub UnaTextBox_TextChanged(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyEventArgs) Handles UnaTextBox.TextChanged

        Static Cronometria = False

        Dim Tiempo1 As Integer

        Dim Tiempo2 As Integer

        Dim TiempoResult As Integer

        If Cronometria Then

            Tiempo2 = Now.Millisecond

            TiempoResult = Tiempo2 - Tiempo1

            ' Cronometria = False           ''' Attencion : saber cuando reiniciar y calcular un nuevo valor para T1

            MessageBox.Show(TiempoResult)   ''' Exploitar el tiempo medido

        Else

            Tiempo1 = Now.Millisecond

            Cronometria = True

        End If

End Sub

Public Class Form2

    Dim sw As New Stopwatch

    Private Sub TextEdit1_GotFocus(sender As Object, e As EventArgs) Handles TextEdit1.GotFocus

        TextEdit1.SelectAll

    End Sub

    Private Sub TextEdit1_KeyDown(sender As Object, e As KeyEventArgs) Handles TextEdit1.KeyDown

        sw.Start

        Label1.Text = sw.ElapsedMilliseconds.ToString

    End Sub

    Private Sub TextEdit1_KeyUp(sender As Object, e As KeyEventArgs) Handles TextEdit1.KeyUp

        Label2.Text = sw.ElapsedMilliseconds.ToString

        sw.Stop

        sw.Reset

        Label3.Text = (CType(Label1.Text , Integer) + CType(Label2.Text , Integer)).ToString

        If CType(Label3.Text,Integer ) > 0  And (CType(Label3.Text,Integer ) <= 10) Then

            Label4.Text = "Lector"

        Else

            Label4.Text = "Teclado"

            TextEdit1.Focus

        End If

    End Sub

    Private Sub TextEdit1_Leave(sender As Object, e As EventArgs) Handles TextEdit1.Leave

        If Label4.Text = "Teclado" Or String.IsNullOrEmpty(TextEdit1.Text) Then

            TextEdit1.Focus

        End If

    End Sub