Refactor select-if statement with lot of duplicate code

[MrNorth]

Hi!

I came across this piece of code today:

Public Class Form1
    'Viewmodel stuff that binds to a UI
    Private Property ShowA1 As Boolean
    Private Property ShowA2 As Boolean
    Private Property ShowB1 As Boolean
    Private Property ShowB2 As Boolean
    Private Property ShowC1 As Boolean
    Private Property ShowC2 As Boolean


    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        Dim dummyList As New List(Of Axis)

        dummyList.Add(New Axis With {.Name = "A", .TypeOfUnit = TypeOfUnit.Unit1})
        dummyList.Add(New Axis With {.Name = "B", .TypeOfUnit = TypeOfUnit.Unit2})
        dummyList.Add(New Axis With {.Name = "C", .TypeOfUnit = TypeOfUnit.Unit3})

        ShowOrHideUIStuff(dummyList)
    End Sub

    Private Sub ShowOrHideUIStuff(list As List(Of Axis))
        For Each axis As Axis In list
            Select Case axis.Name
                Case "A"
                    If (axis.TypeOfUnit = TypeOfUnit.Unit1) Then
                        ShowA1 = True
                        ShowA2 = False
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit2) Then
                        ShowA1 = False
                        ShowA2 = True
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit3) Then
                        ShowA1 = True
                        ShowA2 = True
                    End If
                Case "B"
                    If (axis.TypeOfUnit = TypeOfUnit.Unit1) Then
                        ShowB1 = True
                        ShowB2 = False
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit2) Then
                        ShowB1 = False
                        ShowB2 = True
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit3) Then
                        ShowB1 = True
                        ShowB2 = True
                    End If
                Case "C"
                    If (axis.TypeOfUnit = TypeOfUnit.Unit1) Then
                        ShowC1 = True
                        ShowC2 = False
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit2) Then
                        ShowC1 = False
                        ShowC2 = True
                    ElseIf (axis.TypeOfUnit = TypeOfUnit.Unit3) Then
                        ShowC1 = True
                        ShowC2 = True
                    End If
            End Select
        Next
    End Sub
End Class


Public Class Axis
    Public Property Name As String
    Public Property TypeOfUnit As TypeOfUnit

End Class

Public Enum TypeOfUnit
    Unit1 = 1 ' Show one axis in the plot
    Unit2 = 2 ' Show another type of axis in the plot
    Unit3 = 3 ' Show both axises in the plot
End Enum

It is from a viewmodel, where some axis on a graph is bound to boolean properties. The code is rewritten a bit to make it easier to understand, I removed some MVVM stuff. Basically, some curve datapoints and some metadata is fetched from the database through a business object. The viewmodel get a list of axis that it is supposed to show/hide depending on configuration. Each axis has a name, and some unit type which is an enum.

The list of axis are passed through that big smelly select case statement and everything works fine. But the code itself doesn't look good. I stated thinking about how to refactor the code. Two things came into mind, dictionaties and polymorphism. But I couldn't quite figure out how either of those would help out here. I could subclass axis to a AAxis, BAxis and CAxis but that wouldn't help much, because of the relation to the properties on the viewmodel (the booleans at top) They need to be set properly for the plot to be displayed according to the config. The plot is nothing we can change for now. We simply need to set these pesky booleans.

One thing I thought about that could help some was to introduce some helper properties to the Axis class like this

 Private Sub ShowOrHideUIStuff(list As List(Of Axis))
        For Each axis As Axis In list
            Select Case axis.Name
                Case "A"
                    ShowA1 = axis.Show1
                    ShowA2 = axis.Show2
                Case "B"
                    ShowB1 = axis.Show1
                    ShowB2 = axis.Show2
                Case "C"
                    ShowC1 = axis.Show1
                    ShowC2 = axis.Show2
            End Select
        Next
    End Sub


Public Class Axis
    Public Property Name As String
    Public Property TypeOfUnit As TypeOfUnit
    Public ReadOnly Property Show1 As Boolean
        Get
            If (TypeOfUnit = TypeOfUnit.Unit1) Then
                Return True
            ElseIf (TypeOfUnit = TypeOfUnit.Unit2) Then
                Return False
            ElseIf (TypeOfUnit = TypeOfUnit.Unit3) Then
                Return True
            Else : Return False
            End If
        End Get
    End Property

    Public ReadOnly Property Show2 As Boolean
        Get
            If (TypeOfUnit = TypeOfUnit.Unit1) Then
                Return False
            ElseIf (TypeOfUnit = TypeOfUnit.Unit2) Then
                Return True
            ElseIf (TypeOfUnit = TypeOfUnit.Unit3) Then
                Return True
            Else : Return False
            End If
        End Get
    End Property

But that doesn't feel too good either. I dont really like logic in properties, plus we want to keep the data as generic as possible since we might decide to replace the current plot component, and that might not have these pesky booleans that control it's state (not a primary requirement though). It also feels like the code in the Show1 and Show2 properties could be refactored further?

What do you think, is there cleaner way to handle this? I like polymorphism, but in this case I can't see how it would help us?

/H

[ident]

So is there any thing wrong with your code?

[MrNorth]

So is there any thing wrong with your code?

Well it works, but code that works is not always good code...

Like I stated

But that doesn't feel too good either. I dont really like logic in properties, plus we want to keep the data as generic as possible since we might decide to replace the current plot component, and that might not have these pesky booleans that control it's state (not a primary requirement though). It also feels like the code in the Show1 and Show2 properties could be refactored further?

Cheers
/Henrik