Memory leak Directory.GetFiles() VB.NET - vb.net

Question

I have a launcher utility I wrote that uses Directory.GetFiles() on a Timer to keep track of shortcuts in the start menu.
It has a memory leak, however. I'm not doing anything strange, so I don't understand why it's leaking... I leave the program open and after a few days, it's at 300mb. I used the CLR Profiler to try to locate the leak and it says the memory leakage is coming from String instances allocated by Directory.GetFiles and Directory.GetFileNameWithoutExtension Here's the code I'm using:
Private Sub tmr_Tick(ByVal sender As Object, ByVal e As System.EventArgs) Handles tmr.Tick
IndexStartMenu()
GC.Collect()
End Sub
Private Sub IndexStartMenu()
Dim startMenu As IO.DirectoryInfo
Dim shortcuts() As IO.FileInfo
'Enumerate current user's start menu
startMenu = New IO.DirectoryInfo(Environment.GetFolderPath(Environment.SpecialFolder.StartMenu))
shortcuts = startMenu.GetFiles("*.lnk", IO.SearchOption.AllDirectories)
For Each lnk As IO.FileInfo In shortcuts
Dim newRow As DataRow = dtApps.NewRow
newRow("Application") = IO.Path.GetFileNameWithoutExtension(lnk.FullName)
newRow("Window") = "Launch"
newRow("Hwnd") = ""
newRow("IsShortcut") = True
newRow("ShortcutPath") = lnk.FullName
dtApps.LoadDataRow(newRow.ItemArray, LoadOption.Upsert)
newRow = Nothing
Next
'Enumerate all users' start menu
startMenu = New IO.DirectoryInfo(allUsersStartMenuPath)
shortcuts = startMenu.GetFiles("*.lnk", IO.SearchOption.AllDirectories)
For Each lnk As IO.FileInfo In shortcuts
Dim newRow As DataRow = dtApps.NewRow
newRow("Application") = IO.Path.GetFileNameWithoutExtension(lnk.FullName)
newRow("Window") = "Launch"
newRow("Hwnd") = ""
newRow("IsShortcut") = True
newRow("ShortcutPath") = lnk.FullName
dtApps.LoadDataRow(newRow.ItemArray, LoadOption.Upsert)
newRow = Nothing
Next
'Trying to fix memory usage
startMenu = Nothing
Array.Clear(shortcuts, 0, shortcuts.Length)
shortcuts = Nothing
End Sub

Answer 1

Based on the method you posted, wouldn't the timer just fire every interval and add the contents of those directories repeatedly? If dtApps is a DataTable field scoped to the class which persists for the duration of the application, you are just repeatedly adding the rows to the DataTable causing it to grow. It is not a memory leak, but a natural event. Check the row count of your dtApps. My guess is that you are intending to only add new rows.
Also, you could improve the solution above and eliminate the need to poll the two directories based on a timer by employing a FileSystemWatcher. The FileSystemWatcher will notify you by firing an event when there is a change to the file system.