Saving a System.Drawing.Bitmap to a WinRT StorageFile

Question

I am having a strange issue where I am able to save a System.Drawing.Bitmap to a StorageFile using WinRT APIs when testing my app, but when the app is installed it does not work.

Here is the code in question.

StorageFolder historyFolder = await  ApplicationData.Current.LocalFolder.CreateFolderAsync("history", CreationCollisionOption.OpenIfExists);
StorageFile imageFile = await historyFolder.CreateFileAsync(filename, CreationCollisionOption.ReplaceExisting);

using var stream = new MemoryStream();
image.Save(stream, ImageFormat.Png);
byte[] byteArray = stream.ToArray();

using var randomAccessStream = await imageFile.OpenAsync(FileAccessMode.ReadWrite);
using var outputStream = randomAccessStream.GetOutputStreamAt(0);
using var dataWriter = new DataWriter(outputStream);

dataWriter.WriteBytes(byteArray);
await dataWriter.StoreAsync();
dataWriter.DetachStream();
await outputStream.FlushAsync();

Any idea why this would fail when installed but work fine when running from VS2022 (debug and release mode)?

I have tried the default Bitmap.Save(directory/stream) but that doesn't work either (fails in the same way).

This is the exception thrown when trying to save the Bitmap:

Unhandled exception: System.UnauthorizedAccessException: Access to the path 'C:\Program Files\WindowsApps\40087JoeFinApps.TextGrab_4.1.3.0_x64__kdbpvth5scec4\Text-Grab\history' is denied.
   at System.IO.FileSystem.CreateDirectory(String fullPath, Byte[] securityDescriptor)
   at System.IO.Directory.CreateDirectory(String path)
   at Text_Grab.Services.HistoryService.SaveToHistory(HistoryInfo infoFromFullscreenGrab)
   at Text_Grab.Views.FullscreenGrab.RegionClickCanvas_MouseUp(Object sender, MouseButtonEventArgs e)
   at System.Threading.Tasks.Task.<>c.<ThrowAsync>b__128_0(Object state)
   at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
   at System.Windows.Threading.ExceptionWrapper.TryCatchWhen(Object source, Delegate callback, Object args, Int32 numArgs, Delegate catchHandler)

Answer 1

Because the unpackaged application lacks package identity, it does not support the Windows.Storage API.

It is recommended that you use System.IO.File to handle storage in unpackaged app.