Issue with item order in List and CheckedListBox - vb.net

Question

I have 2 CheckedListBox that contains 3 strings each:
CheckedListBox1: "Apricot", "Banana", "Cherry"
CheckedListBox2: "Apple", "Blueberry", "Clementine"
I would like that everytime I click on my Button1, it checks if it contains the item, and if not it adds it to myList1 for CheckedListBox1, and myList2 for CheckedListBox2, but in the same order. I mean:
I check Apricot and Cherry, so myList1 is: "Apricot", "Cherry"
I uncheck them and check only Banana, so the list is: "Apricot", "Cherry", "Banana"
So I want the Apricot always being first, Banana second and Cherry third.
Same for myList2, obviously.
My actual code is:
Dim myList1 As New List(Of String)
Dim myList2 As New List(Of String)
Dim myFullList As New List(Of String)
Private Sub Submit() Handles Button1.Click
For Each item In CheckedListBox1.CheckedItems
If Not myList1.Contains(item) Then
myList1.Add(item)
End If
Next
For Each item In CheckedListBox2.CheckedItems
If Not myList2.Contains(item) Then
myList2.Add(item)
End If
Next
myFullList.Add(String.Join(", ", myList1)
myFullList.Add(String.Join(", ", myList2)
End Sub
Thanks in advance, guys ! :)

Answer 1

You might consider doing things a bit differently. Define a custom type and bind a list of that type to the CheckedListBox. When an item is checked, set a flag in that item. You can then just get the items from that list that have that flag set.
Public Class CheckListItem
Public Property Text As String
Public Property Checked As Boolean
Public Overrides Function ToString() As String
Return Text
End Function
End Class
Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim items = {New CheckListItem With {.Text = "Apricot"},
New CheckListItem With {.Text = "Banana"},
New CheckListItem With {.Text = "Cherry"}}
CheckedListBox1.DataSource = items
End Sub
Private Sub CheckedListBox1_ItemCheck(sender As Object, e As ItemCheckEventArgs) Handles CheckedListBox1.ItemCheck
If e.NewValue = CheckState.Checked Then
DirectCast(CheckedListBox1.Items(e.Index), CheckListItem).Checked = True
End If
End Sub
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim checkedItems = CheckedListBox1.Items.Cast(Of CheckListItem)().Where(Function(cli) cli.Checked)
MessageBox.Show(String.Join(", ", checkedItems))
End Sub