Why is each String being written to a different file? - vb.net

Question

I am trying to generate a size-based list of files. The current size being passed is 10 MB worth of file-names per text file. Instead of it counting to 10 MB and then incrementing the version letter, it is writing each file-name to its own individual file. This is strange as each file is ~150 kb, but I cannot figure out why it is reporting total as > number every time the code loops.
Private Function GenerateListsForSize(source As String, destination As String, name As String, number As Integer)
Dim files As ArrayList = New ArrayList
Dim total As Integer
Dim version As Char = "A"
Dim path As String
Dim counter As Integer = 0
Dim passTexts As ArrayList = New ArrayList
Dim infoReader As System.IO.FileInfo
For Each foundFile As String In My.Computer.FileSystem.GetFiles(source)
files.Add(foundFile)
Next
If files.Count > 1 Then 'If files exist in dir, count them and get how many lists
path = destination & "\" & name & version & ".txt"
Dim fs As FileStream = File.Create(path) 'creates the first text file
fs.Close()
passTexts.Add(path)
For Each foundfile As String In files
Using sw As StreamWriter = New StreamWriter(path)
Console.WriteLine(foundfile)
sw.WriteLine(foundfile)
End Using
infoReader = My.Computer.FileSystem.GetFileInfo(foundfile)
total = total + infoReader.Length
If total >= number Then 'If max file size is reached
version = Chr(Asc(version) + 1) 'Increments Version
path = destination & "\" & name & version & ".txt" 'Corrects path
fs = File.Create(path) 'creates the new text file with updated path
fs.Close()
passTexts.Add(path)
total = 0 'resets total
End If
Next
End If
Return passTexts
End Function

Answer 1

Every time through the loop, you open the file (using the StreamWriter) which overwrites the previous contents. Your file will only ever have one filename inside it. Instead of opening and writing every time through the loop, only write the file when you have accumulated all the filenames. I removed the calls to File.Create as they aren't necessary. The StreamWriter will create the file if it doesn't exist. And I changed the ArrayList's to List(Of String) since they're easier to work with. Also, be sure to turn Option Strict On. This code has not been tested, but it should get my point across. I hope I haven't misunderstood what you were trying to do.
Private Function GenerateListsForSize(source As String, destination As String, name As String, number As Integer) As List(Of String)
Dim files As New List(Of String)()
Dim filenamesToWrite As New List(Of String)()
Dim total As Integer
Dim version As Char = "A"
Dim filename As String
Dim counter As Integer = 0
Dim passTexts As New List(Of String)()
Dim infoReader As System.IO.FileInfo
files.AddRange(My.Computer.FileSystem.GetFiles(source))
If files.Count > 1 Then 'If files exist in dir, count them and get how many lists
'Path.Combine is preferable to concatenating strings.
filename = Path.Combine(destination, String.Format("{0}{1}.txt", name, version))
passTexts.Add(filename)
For Each foundfile As String In files
filenamesToWrite.Add(foundfile)
infoReader = My.Computer.FileSystem.GetFileInfo(foundfile)
total = total + infoReader.Length
If total >= number Then 'If max file size is reached
'Only write when the list is complete for this batch.
Using sw As StreamWriter = New StreamWriter(filename)
For Each fname As String In filenamesToWrite
Console.WriteLine(foundfile)
sw.WriteLine(foundfile)
Next
End Using
version = Chr(Asc(version) + 1) 'Increments Version
filename = Path.Combine(destination, String.Format("{0}{1}.txt", name, version)) 'corrects path
passTexts.Add(filename) 'IS THIS A DUPLICATE????
total = 0 'resets total
filenamesToWrite.Clear() 'clear the list of file names to write
End If
Next
End If
Return passTexts
End Function