asked on

Filter GetFiles() by file name and select one random file.

I am reading the contents of a Directory using VB.net and the FileInfo() and GetFiles commmands.

Dim DirectoryLocation As New IO.DirectoryInfo("c:\somedir")
Dim FileArray As IO.FileInfo() = DirectoryLocation.GetFiles("*.jpg")
Dim FilesInFolder As IO.FileInfo

This code will return several results:
thumb_somefile.jpg
somefile.jpg
thumb_anotherfile.jpg
anotherfile.jpg

I want to eliminate the files starting with "thumb_" from the list and then select one random file from those results.

I am trying to select a random background image for a webpage from a folder on the server.

I have spent all day on this so far. this code will select a random item from the GetFiles() Array
FileArray(RandString.[Next](0, FileArray.Length)) but before i do that i need to remove the files that contain "thumb" in the file name.

I have tried the FILTER command on the GetFiles() array but i throws an error due to the array type.

any help you can throw my way would be greatly appreciated!

thanks!

kaufmed

If you're using .NET 3.x or above, you could throw in some Linq:

Dim DirectoryLocation As New IO.DirectoryInfo("c:\somedir")
Dim FileArray As IO.FileInfo() = DirectoryLocation.GetFiles("*.jpg")
Dim FilesInFolder As IO.FileInfo

FileArray = (From item As IO.FileInfo In FileArray _
            Where Not item.Name.StartsWith("thumb_") _
            Select item).ToArray()

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ladarling

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kaufmed

@ladarling

I think he mean "eliminate" the files from the list, not delete the image file entirely.

larkvale

Try something like this ...

Dim RandomFileName as String = ""

Do

RandomFileName = FileArray(RandString.[Next](0, FileArray.Length))

Loop While(RandomFileName.ToLower().StartsWith("thumb_"))

If RandomFileName <> "" Then
' use the random file name here
End If

Zhaolai

Try this:

Dim DirectoryLocation As New IO.DirectoryInfo("c:\somedir")
Dim FileArray As IO.FileInfo() = DirectoryLocation.GetFiles("*.jpg")
Dim newFileArray As IO.FileInfo() = Nothing
Dim count As Integer
For Each oInfo As FileInfo In FileArray
If oInfo.Name.StartsWith("thumb_", System.StringComparison.CurrentCultureIgnoreCase) = False Then
count += 1
Array.Resize(newFileArray, count)
newFileArray(count - 1) = oInfo
End If
Next

Now newFileArray will hold the files without "thumb_".

ladarling

@kaufmed..... Oh, ok... gotcha...
Then, a non-Linq way would be:

    Dim FileArray As IO.FileInfo()
        Dim GoodFiles As New List(Of IO.FileInfo)
        For Each f As IO.FileInfo In FileArray
            If Not f.Name.StartsWith("thumb") Then
                GoodFiles.Add(f)
            End If
        Next
 FileArray = GoodFiles.ToArray

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Mike Tomlinson

Love all the ways to do it...here's another one:

        Dim Files As New List(Of IO.FileInfo)
        Files.AddRange(New IO.DirectoryInfo("c:\somedir").GetFiles("*.jpg"))
        Files.RemoveAll(Function(fi As IO.FileInfo) fi.Name.ToLower.StartsWith("thumb_"))
        Dim RandomFile As String = Files(New Random().Next(0, Files.Count)).FullName

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ronayers

ASKER

THANK YOU!