Best Way to Sort GetFiles - vb.net

Question

I am trying to sort the following files in this order:
TMP_SDF_1180741.PDF
TMP_SDF_1179715.PDF
TMP_SDF_1162371.PDF
TMP_SDF_1141511.PDF
TMP_SDF_1131750.PDF
TMP_SDF_1117362.PDF
TMP_SDF_1104199.PDF
TMP_SDF_1082698.PDF
TMP_SDF_1062921.PDF
TMP_SDF_1043875.PDF
TMP_SDF_991514.PDF
TMP_SDF_970621.PDF
TMP_SDF_963154.PDF
TMP_SDF_952954.PDF
TMP_SDF_948067.PDF
TMP_SDF_917669.PDF
TMP_SDF_904315.PDF
TMP_SDF_899902.PDF
TMP_SDF_892398.PDF
TMP_SDF_882024.PDF
But the actual output is this:
TMP_SDF_991514.PDF
TMP_SDF_970621.PDF
TMP_SDF_963154.PDF
TMP_SDF_952954.PDF
TMP_SDF_948067.PDF
TMP_SDF_917669.PDF
TMP_SDF_904315.PDF
TMP_SDF_899902.PDF
TMP_SDF_892398.PDF
TMP_SDF_882024.PDF
TMP_SDF_1180741.PDF
TMP_SDF_1179715.PDF
TMP_SDF_1162371.PDF
TMP_SDF_1141511.PDF
TMP_SDF_1131750.PDF
TMP_SDF_1117362.PDF
TMP_SDF_1104199.PDF
TMP_SDF_1082698.PDF
TMP_SDF_1062921.PDF
TMP_SDF_1043875.PDF
I have tried researching sort methods by GetFiles but when I apply them, i get errors about system collections not able to bind to a 1-dimensional array and it is frustrating. Here is my code:
Dim di As New IO.DirectoryInfo("C:\temp")
Dim aryFi As IO.FileInfo() = di.GetFiles("*.PDF")
Dim fi As IO.FileInfo
For Each fi In aryFi
My.Computer.FileSystem.RenameFile("C:\TEMP\" & fi.Name, listBox1.SelectedItem.ToString & ".pdf")
listBox1.SelectedIndex = listBox1.SelectedIndex - 1
Next
I am renaming files to be a1 a2 a3 etc so that when I combine in PDF, they are in chronological order. The way i want the sorting, will place them in chronological order. I am sure there is an easier way. As you can tell, the higher the number in the PDF file (1180741) the most recent date of the content of the file. While 882024 would be the oldest file content.

Answer 1

As has been stated in the comments, you need to sort them numerically rather than alphabetically. I don't know the specific sorting algorithm that is used by Windows Explorer, or if it's possible to use the same library, but it's certainly possible to write your own algorithm that sorts however you want.
The first step in doing that is to extract just the numeric part that you want to use as the sort key. Without knowing more details, it's hard to say what the best option for that would be. If you know that the number always starts at a particular character position in the string, you could simply use String.SubString. If it's always delimited by "_" and "." you could use String.Split. If you need something more complex, or if you need the parsing rules to be configurable, you may want to consider using RegEx. As an example, here's a simple example method that uses String.Split:
Public Function GetSortKey(fileName As String) As Integer
Return Integer.Parse(fileName.Split({"_"c, "."c})(2))
End Function
Once you have a method that extracts the sort key for a given file name, you can use it to sort them like this:
di.GetFiles("*.PDF").OrderBy(Function(x) GetSortKey(x.Name))

Answer 2

Perhaps you could take advantage of some tools that you have at your hands
Dim reg As RegEx = new RegEx("\d+")
Dim ordered = new List(Of OrderedFiles)()
for each s in Directory.GetFiles("C:\temp", "*.PDF")
Dim aFile = new OrderedFiles()
aFile.FileName = s
aFile.Sequence = Convert.ToInt32(reg.Match(s).Value)
ordered.Add(aFile)
Next
for each aFile in ordered.OrderByDescending(Function(x) x.Sequence)
Console.WriteLine(Path.GetFileName(aFile.FileName))
Next
End Sub
Class OrderedFiles
Public FileName as String
Public Sequence as Integer
End Class
In this example you have a custom class with the filename and the numeric part that you want to sort. Then a Regex expression that matches any numeric value in your files is applied to your files to build a instance of the class with the name and the numeric part. At the end of the loop just call the Linq method that orders your list by descending order