Question

For some reason, it seems that the outer block doesn’t seem to update recursively, as I expected it to. I want the loops to add all directories within "C:\Users\Drise"to the array internaldirs(). Any advice on the correct way to do this, as it seems I’m doing it improperly?

Static internaldirs() As String

internaldirs.add("C:\Users\Drise")

For Each internaldir As String In internaldirs
    For Each direc As String In Directory.GetDirectories(internaldir)
        internaldirs.Add(direc)
    Next
Next

Solution:

Sub recursivedirs()
    Static internaldirs As New List(Of String)
    Try
        If internaldirs(0) = "C:\Users\Drise" Then
            Call AddDirToList(internaldirs, internaldirs(0))
        End If
    Catch
        internaldirs.Add("C:\Users\Drise")
        Call AddDirToList(internaldirs, internaldirs(0))
    End Try

End Sub

Private Sub AddDirToList(ByRef dirs As List(Of String), ByVal currentDir As String)
    dirs.Add(currentDir)
    Try
        For Each subDir As String In Directory.GetDirectories(currentDir)
            AddDirToList(dirs, subDir)
        Next
    Catch
    End Try

Answer 1

As Andrew Cooper said, you can’t modify a collection being used in a For Each loop.

You can do it with an index counter.

Dim internaldir As List(Of String)
internaldir.Add("C:\Users\Drise")
Dim i As Integer = 0
Do Until i >= internaldir.Count
    Dim internaldir As String = internaldirs(i)
    For Each currentdir As String In Directory.GetDirectories(internaldir)
        internaldirs.Add(currentdir)
    Next
    i += 1
Loop
' If you want an array as output, use:
Dim array As String() = internaldirs.ToArray()