Private Sub TextBox1_TextChanged(sender As System.Object, e As _
      System.EventArgs) _
        Handles TextBox1.TextChanged
        Select Case TextBox1.Text
            Case 1
                TextBox1.BackColor = Color.Red
            Case 1.5
                TextBox1.BackColor = Color.Orange
            Case 2
                TextBox1.BackColor = Color.Green
            Case Else
                TextBox1.BackColor = Color.GhostWhite
        End Select
    End Sub