UWP C# Getting All Files From Selected Folder

Question

I'm trying to get a list of all files in a selected folder using UWP and C#. I need to select a folder and display all audio files in that folder (including subfolders of the root folder

I have the following code:

        var folderPicker = new FolderPicker();
        folderPicker.SuggestedStartLocation = PickerLocationId.Desktop;
        folderPicker.FileTypeFilter.Add("*");

        StorageFolder folder = await folderPicker.PickSingleFolderAsync();

        List<string> fileTypeFilter = new List<string>();
        fileTypeFilter.Add(".mp3");
        fileTypeFilter.Add(".mp3");
        fileTypeFilter.Add(".wma");
        fileTypeFilter.Add(".wav");
        fileTypeFilter.Add(".ogg");
        fileTypeFilter.Add(".flac");
        fileTypeFilter.Add(".aiff");
        fileTypeFilter.Add(".aac");

        QueryOptions queryOptions = new QueryOptions(CommonFileQuery.OrderByDate, fileTypeFilter);

        StorageFileQueryResult results = folder.CreateFileQueryWithOptions(queryOptions);

        IReadOnlyList<StorageFile> sortedFiles = await results.GetFilesAsync();
        foreach (StorageFile item in sortedFiles)
        {
            AudioFilesLV.Items.Add(item.Path.ToString());
        }

However once I select the folder I get the following error:

System.ArgumentException: 'Value does not fall within the expected range.'

The folder I am selecting contains around 100 MP3 files

Does anyone have any idea what I am doing wrong?

Thanks in advance

Answer 1

Seems to be a known issue with the CommonFileQuery.OrderByDate. Apparently you can only use CommonFileQuery.OrderByDate with the folders in the KnownFolders enumeration. If I change your code to use CommonFileQuery.DefaultQuery it works.

https://social.msdn.microsoft.com/Forums/vstudio/en-US/f99384d9-5460-4fd4-8c70-5694e1370432/a-exception-is-happen-when-calling-getfilesasync-with-parameter-of-commonfilequeryorderbydate?forum=wpdevelop

You could just use an OrderBy as follows if they aren't coming back in date order:

foreach (StorageFile item in sortedFiles.OrderBy(a => a.DateCreated))