BitmapDecoder.Create does not handle FileStream with FileOptions.Asynchronous

• .NET Core Version: (e.g. 3.0 Preview1, or daily build number, use dotnet --info) 5.0.201
• Windows version: (winver) 19042.867
• Does the bug reproduce also in WPF for .NET Framework 4.8?: Yes/No Yes.

Problem description:

BitmapDecoder.Create throws ArgumentException (“Value does not fall within the expected range.”) whenever the stream argument is FileStream with FileOptions.Asynchronous.

Actual behavior:

at System.Windows.Media.Imaging.BitmapDecoder.SetupDecoderFromUriOrStream(Uri uri, Stream stream, BitmapCacheOption cacheOption, Guid& clsId, Boolean& isOriginalWritable, Stream& uriStream, UnmanagedMemoryStream& unmanagedMemoryStream, SafeFileHandle& safeFilehandle)
  at System.Windows.Media.Imaging.BitmapDecoder.CreateFromUriOrStream(Uri baseUri, Uri uri, Stream stream, BitmapCreateOptions createOptions, BitmapCacheOption cacheOption, RequestCachePolicy uriCachePolicy, Boolean insertInDecoderCache)
  at System.Windows.Media.Imaging.BitmapDecoder.Create(Stream bitmapStream, BitmapCreateOptions createOptions, BitmapCacheOption cacheOption)

Expected behavior:

BitmapDecoder.Create shouldn’t throw an exception.

Minimal repro:

using var fs = new FileStream("image.jpg",
	FileMode.Open,
	FileAccess.Read,
	FileShare.Read,
	4096,
	FileOptions.Asynchronous);

var decoder = BitmapDecoder.Create(fs, BitmapCreateOptions.PreservePixelFormat, BitmapCacheOption.None);

[lindexi]

@vonzshik I fixed it, see https://github.com/dotnet/wpf/pull/4966

I follow your opinion, when I judge this file is asynchronous, I read the file into memory.

I wrote a demo code, and it work well. See https://github.com/lindexi/lindexi_gd/tree/20b78c5547b2ecacdd244a438ef58518469a91d7/GeafakaijawkeheahemLejeehocear

You can test the demo by publish the code with self contained.

dotnet publish --self-contained -r win-x86

[dipeshmsft]

We have taken this PR for the current Community Test Pass. Thanks for the contribution.