VB.net file handling progresses to slowly - vb.net

Question

Hi i have a app that takes a list of files and searches each file for all the images referenced within each file. When the list is finished I sort and remove duplicates from the list then copy each item/image to a new folder. It works, but barely. I takes hours for the copying to occur on as little as 500 files. Doing the copying in windows explorer if faster, and that defeats the purpose of the application.
I don't know how to streamline it better. Your inputs would be greatly appreciated.
'Remove Dupes takes the list of images found in each file and removes any duplicates
Private Sub RemoveDupes(ByRef Items As List(Of String), Optional ByVal NeedSorting As Boolean = False)
statusText = "Removing duplicates from list."
Dim Temp As New List(Of String)
Items.Sort()
'Remove Duplicates
For Each Item As String In Items
'Check if item is in Temp
If Not Temp.Contains(Item) Then
'Add item to list.
Temp.Add(Item)
File.AppendAllText(ListofGraphics, Item & vbNewLine)
End If
Next Item
'Send back new list.
Items = Temp
End Sub
'GetImages does the actual copying of files from the list RemoveDup creates
Public Sub GetImages()
Dim imgLocation = txtSearchICN.Text
' Get the list of file
Dim fileNames As String() = System.IO.Directory.GetFiles(imgLocation)
Dim i As Integer
statusText = "Copying image files."
i = 0
For Each name As String In GraphicList
i = i + 1
' See whether name appears in fileNames.
Dim found As Boolean = False
' Search name in fileNames.
For Each fileName As String In fileNames
' GraphicList consists of filename without extension, so we compare name
' with the filename without its extension.
If Path.GetFileNameWithoutExtension(fileName) = name Then
Dim FileNameOnly = Path.GetFileName(fileName)
' Debug.Print("FileNameOnly: " & FileNameOnly)
Dim copyTo As String
copyTo = createImgFldr & "\" & FileNameOnly
System.IO.File.Copy(fileName, copyTo)
File.AppendAllText(ListofFiles, name & vbNewLine)
'items to write to rich text box in BackgroundWorker1_ProgressChanged
imgFilename = (name) + vbCrLf
ImageCount1 = i
' Set found to True so we do not process name as missing, and exit For. \
found = True
Exit For
Else
File.AppendAllText(MissingFiles, name & vbNewLine)
End If
Next
status = "Copying Graphic Files"
BackgroundWorker1.ReportProgress(100 * i / GraphicList.Count())
Next
End Sub
'BackgroundWorker1_ProgressChanged. gets file counts and writes to labels and rich text box
Private Sub BackgroundWorker1_ProgressChanged(sender As Object, e As System.ComponentModel.ProgressChangedEventArgs) Handles BackgroundWorker1.ProgressChanged
'' This event is fired when you call the ReportProgress method from inside your DoWork.
'' Any visual indicators about the progress should go here.
ProgressBar1.Value = e.ProgressPercentage
lblStatus.Text = CType(e.UserState, String)
lblStatus.Text = status & " " & e.ProgressPercentage.ToString & " % Complete "
RichTextBox1.Text &= (fileFilename)
RichTextBox1.Text &= (imgFilename)
txtImgCount.Text = ImageCount1
Label8.Text = statusText
fileCount.Text = fCount
End Sub

Answer 1

I would change something in your code to avoid the constant writing to a file at each loop and the necessity to have two loops nested.
This is a stripped down version of your GetFiles intended to highlight my points:
Public Sub GetImages()
' Two list to collect missing and found files
Dim foundFiles As List(Of String) = New List(Of String)()
Dim notfoundFiles As List(Of String) = New List(Of String)()
Dim fileNames As String() = System.IO.Directory.GetFiles(imgLocation)
' Loop over the filenames retrieved
For Each fileName As String In fileNames
' Check if the files is contained or not in the request list
If GraphicList.Contains(Path.GetFileNameWithoutExtension(fileName)) Then
Dim FileNameOnly = Path.GetFileName(fileName)
Dim copyTo As String
copyTo = createImgFldr & "\" & FileNameOnly
System.IO.File.Copy(fileName, copyTo)
' Do not write to file inside the loop, just add the fact to the list
foundFiles.Add(FileNameOnly)
Else
notfoundFiles.Add(FileNameOnly)
End If
Next
' Write everything outside the loop
File.WriteAllLines(listofFiles, foundFiles)
File.WriteAllLines(MissingFiles, notfoundFiles)
End Sub