Remove items from a listbox if it appears in another - vb.net

Question

I have 2 listbox's on my form. The first populates from an array and displays files names that relate to the value of a Date Time picker. When that item is double clicked it moves over to the 2nd list box, clears from the 1st and the relevant files are transferred from one directory to another. The problem I have is that as the population is part of the load event once the application is closed and then re-opened the files names appear in both listbox's.
Is there a way to say if the object appears in 1 textbox then it shouldn't appear in the other?
I've tried the following but re-opening still displays the object in both
Dim item As Object
For Each item In lstPlanned.Items
If lstProgress.Contains(item) Then
lstPlanned.Items.Remove(item)
End If
Next
For the 2nd listbox I'm using the following to populate it
For Each Dir As String In System.IO.Directory.GetDirectories(aMailbox)
Dim dirInfo As New System.IO.DirectoryInfo(Dir)
lstProgress.Items.Add(dirInfo.Name)
Full Load code as follows
Private Sub Main_Load(sender As Object, e As EventArgs) Handles MyBase.Load
Dim loaddate As String = Calendar.Value.ToString("dd/MM/yy")
ReDim AllDetail(0 To 0)
numfiles = 0
lstPlanned.Items.Clear()
Dim allfiles = lynxin.GetFiles("*.txt")
ReDim AllDetails(allfiles.Count)
lstProgress.Items.Clear()
lstPlanned.Items.Add("No Jobs Planned Today!")
lstPlanned.Enabled = False
For Each txtfi In (allfiles)
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
AllDetails(numfiles) = New FileDetail()
AllDetails(numfiles).uPath = Microsoft.VisualBasic.Left((txtfi.FullName), Len(txtfi.FullName) - 4)
AllDetails(numfiles).uFile = Path.GetFileNameWithoutExtension(txtfi.Name)
Dim line = allLines.Where(Function(x) (x.StartsWith("unitname="))).SingleOrDefault()
If line IsNot Nothing Then
AllDetails(numfiles).uName = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("unitcode="))).SingleOrDefault()
If line IsNot Nothing Then
AllDetails(numfiles).uCode = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("opername="))).SingleOrDefault()
If line IsNot Nothing Then
AllDetails(numfiles).uOps = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("plandate="))).SingleOrDefault()
If line IsNot Nothing Then
AllDetails(numfiles).uPlan = line.Split("="c)(1)
End If
line = allLines.Where(Function(x) (x.StartsWith("cliecode="))).SingleOrDefault()
If line IsNot Nothing Then
AllDetails(numfiles).uClient = line.Split("="c)(1)
End If
If AllDetails(numfiles).uPlan = loaddate Then
lstPlanned.Items.Remove("No Jobs Planned Today!")
lstPlanned.Enabled = True
lstPlanned.Items.Insert(0, AllDetails(numfiles).uName & " - " & AllDetails(numfiles).uCode & " - " & AllDetails(numfiles).uOps)
numfiles = numfiles + 1
End If
Next
For Each Dir As String In System.IO.Directory.GetDirectories(aMailbox)
Dim dirInfo As New System.IO.DirectoryInfo(Dir)
lstProgress.Items.Add(dirInfo.Name)
Dim item As Object
For Each item In lstPlanned.Items
If lstProgress.Contains(item) Then
lstPlanned.Items.Remove(item)
End If
Next
Next
End Sub

Answer 1

The Contains method of a listbox checks the controls collections not the items collection. It should have been lstProgress.Items.Contains(item). Also you can use GetDirectories of the DirectoryInfo class to get the directoryinfo objects directly.
Checking to see if lstPlanned contains each item as you add it to lstProgress will eliminate the extra loop, which wouldn't work right anyway, because you're not allowed to modify the iterated collection in a For Each loop.
I was looking over your code and noticed an improvement that could be made. Using the LINQ extension methods each you want to add a property value means a lot of extra iterating through each file line collection. Using select means you only iterate through the collection once.
For Each txtfi In (allfiles)
Dim allLines() As String = File.ReadAllLines(txtfi.FullName)
AllDetails(numfiles) = New FileDetail()
AllDetails(numfiles).uPath = Microsoft.VisualBasic.Left((txtfi.FullName), Len(txtfi.FullName) - 4)
AllDetails(numfiles).uFile = Path.GetFileNameWithoutExtension(txtfi.Name)
AllDetails(numfiles).uPlan = allLines.Where(Function(x) (x.StartsWith("plandate="))).SingleOrDefault().Split("="c)(1)
If AllDetails(numfiles).uPlan = loaddate Then
For Each line In allLines
If line Is Not Nothing Then
Dim fields As String() = line.Split("="c)
Select Case fields(0)
Case "unitname"
AllDetails(numfiles).uName = fields(1)
Case "unitcode"
AllDetails(numfiles).uCode = fields(1)
Case "opername"
AllDetails(numfiles).uOps = fields(1)
Case "plandate"
AllDetails(numfiles).uPlan = fields(1)
Case "cliecode"
AllDetails(numfiles).uClient = fields(1)
End Select
End If
Next
lstPlanned.Items.Remove("No Jobs Planned Today!")
lstPlanned.Enabled = True
lstPlanned.Items.Insert(0, AllDetails(numfiles).uName & " - " & AllDetails(numfiles).uCode & " - " & AllDetails(numfiles).uOps)
numfiles = numfiles + 1
End If
Next
Dim RootDir As New System.IO.DirectoryInfo(aMailbox)
For Each Dir As IO.DirectoryInfo In RootDir.GetDirectories
Dim item = Dir.Name
lstProgress.Items.Add(item)
If lstPlanned.Items.Contains(item) Then
lstPlanned.Items.Remove(item)
End If
Next

Answer 2

Thanks Tinstaafl
Your answer works a treat.
I also adapted your first edit to
Dim RootDir As New System.IO.DirectoryInfo(aMailbox)
For Each Dir As IO.DirectoryInfo In RootDir.GetDirectories
lstProgress.Items.Add(Dir.Name)
'item defaults to object, no need to explicitly declare it
For Each item In New System.Collections.ArrayList(lstPlanned.Items)
If lstProgress.Items.Contains(item) Then
lstPlanned.Items.Remove(item)
End If
Next
Next
amending the following line
For Each item In New System.Collections.ArrayList(lstPlanned.Items)
Thanks again