Inspect file to gather the mime type.
GetMimeType is an extension method for the FileInfo class.
Usage:
[Test()]
[TestCase(@"data\Textdokument.txt", "text/plain")]
[TestCase(@"data\Notify.wav", "audio/wav")]
[TestCase(@"data\Overture.mp3", "audio/mpeg3")]
[TestCase(@"data\Unknowndokument.thisisnotanextension", "unknown/unknown")]
public void TryFilesWhichWorkWithUrlmon(string filename, string mimetype)
{
var fi = new FileInfo(filename);
var mime = fi.GetMimeType();
mime.Should().Be(mimetype);
}