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docs/fundamentals/runtime-libraries/snippets/System/NotSupportedException/Overview/csharp/TestProp2.cs
53 строки
2 KB
Genevieve Warren
Remarks for exception types and Registry class (#38930)
03 янв 2024, 22:30
Не верифицирован
03 янв 2024, 22:30
932bcca
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using System; using System.IO; using System.Threading.Tasks; public class TestPropEx2 { public static async Task Main() { String name = @".\TestFile.dat"; var fs = new FileStream(name, FileMode.Create, FileAccess.Write); Console.WriteLine("Filename: {0}, Encoding: {1}", name, await FileUtilities.GetEncodingType(fs)); } } public class FileUtilities { public enum EncodingType { None = 0, Unknown = -1, Utf8 = 1, Utf16 = 2, Utf32 = 3 } // <Snippet4> public static async Task<EncodingType> GetEncodingType(FileStream fs) { if (!fs.CanRead) return EncodingType.Unknown; Byte[] bytes = new Byte[4]; int bytesRead = await fs.ReadAsync(bytes, 0, 4); if (bytesRead < 2) return EncodingType.None; if (bytesRead >= 3 & (bytes[0] == 0xEF && bytes[1] == 0xBB && bytes[2] == 0xBF)) return EncodingType.Utf8; if (bytesRead == 4) { var value = BitConverter.ToUInt32(bytes, 0); if (value == 0x0000FEFF | value == 0xFEFF0000) return EncodingType.Utf32; } var value16 = BitConverter.ToUInt16(bytes, 0); if (value16 == (ushort)0xFEFF | value16 == (ushort)0xFFFE) return EncodingType.Utf16; return EncodingType.Unknown; } } // The example displays the following output: // Filename: .\TestFile.dat, Encoding: Unknown // </Snippet4>