Hex Dump Anwendung strukturiert nach IOSP/PoMO. Inspiriert durch das Buch "Head First C#". Erklärung s.a. hier: http://blog.ralfw.de/2014/10/responsibilities-zahlen.html Und hier noch der ursprüngliche Brownfield-Code: https://gist.github.com/ralfw/d26ad56ee7310e89ae6d

hexdmperV1.cs

using System;
using System.IO;

namespace headfirst.hexdmper
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			var filename = Get_filename_from_commandline (args);
			Check_if_file_exists (filename);
			Read_blocks_from_file (filename,
				block => {
					var formattedBlock = Format_block(block);
					Print_block(formattedBlock);
				});
		}


		static string Get_filename_from_commandline(string[] args) {
			if (args.Length != 1) {
				Console.Error.WriteLine ("Verwendung: hexdmper Dateiname");
				Environment.Exit (1);
			}
			return args [0];
		}


		static void Check_if_file_exists(string filename) {
			if (!File.Exists (filename)) {
				Console.Error.WriteLine ("Keine derartige Datei: {0}", filename);
				Environment.Exit (2);
			}
		}

		static void Read_blocks_from_file(string filename, Action<Block> onBlock) {
			using (Stream file = File.OpenRead (filename)) {
				var buffer = new byte[16];
				var bytesRead = 0;
				while(true) {
					var block = new Block () { Position = file.Position };

					bytesRead = file.Read (buffer, 0, buffer.Length);
					if (bytesRead == 0) break;

					block.Bytes = new byte[bytesRead];
					Array.Copy(buffer, block.Bytes, bytesRead);

					onBlock(block);
				};
			}
		}


		static FormattedBlock Format_block(Block block) {
			var formattedBlock = new FormattedBlock () { Position = block.Position };

			formattedBlock.HexBytes = Format_block_as_hexbytes (block.Bytes);
			formattedBlock.ASCIIBytes = Format_block_as_ASCIIbytes (block.Bytes);

			return formattedBlock;
		}

		static string[] Format_block_as_hexbytes(byte[] bytes) {
			var hexbytes = new string[16];
			for (var i = 0; i < 16; i++) {
				if (i >= bytes.Length)
					hexbytes [i] = "  ";
				else
					hexbytes [i] = bytes [i].ToString ("x2");
			}
			return hexbytes;
		}

		static string[] Format_block_as_ASCIIbytes(byte[] bytes) {
			var asciiBytes = new string[16];
			for (var i = 0; i < 16; i++) {
				if (i >= bytes.Length)
					asciiBytes [i] = ".";
				else
					asciiBytes [i] = bytes [i] >= 32 && bytes [i] <= 250 
									 ? char.ConvertFromUtf32(bytes[i])
								     : ".";
			}
			return asciiBytes;
		}


		static void Print_block(FormattedBlock block) {
			Console.Write ("{0:00000000}: ", block.Position);
			foreach (var hb in block.HexBytes)
				Console.Write ("{0} ", hb);
			foreach (var ab in block.ASCIIBytes)
				Console.Write ("{0}", ab);
			Console.WriteLine ();
		}


		class Block {
			public long Position;
			public byte[] Bytes;
		}
			
		class FormattedBlock {
			public long Position;
			public string[] HexBytes;
			public string[] ASCIIBytes;
		}
	}
}

hexdmperV2.cs

using System;
using System.IO;

namespace headfirst.hexdmper
{
	class MainClass
	{
		public static void Main (string[] args)
		{
			var cmd = new CommandlineProvider ();
			var filesys = new FilesystemProvider ();
			var format = new Formatter ();
			var console = new ConsoleProvider ();

			var filename = cmd.Get_filename (args);
			filesys.Check_if_file_exists (filename);
			filesys.Read_blocks_from_file (filename,
				block => {
					var formattedBlock = format.Format_block(block);
					console.Print_block(formattedBlock);
				});
		}
	}



	class CommandlineProvider {
		public string Get_filename(string[] args) {
			if (args.Length != 1) {
				Console.Error.WriteLine ("Verwendung: hexdmper Dateiname");
				Environment.Exit (1);
			}
			return args [0];
		}
	}



	class FilesystemProvider {
		public void Check_if_file_exists(string filename) {
			if (!File.Exists (filename)) {
				Console.Error.WriteLine ("Keine derartige Datei: {0}", filename);
				Environment.Exit (2);
			}
		}

		public void Read_blocks_from_file(string filename, Action<Block> onBlock) {
			using (Stream file = File.OpenRead (filename)) {
				var buffer = new byte[16];
				var bytesRead = 0;
				while(true) {
					var block = new Block () { Position = file.Position };

					bytesRead = file.Read (buffer, 0, buffer.Length);
					if (bytesRead == 0) break;

					block.Bytes = new byte[bytesRead];
					Array.Copy(buffer, block.Bytes, bytesRead);

					onBlock(block);
				};
			}
		}
	}

	class Block {
		public long Position;
		public byte[] Bytes;
	}



	class Formatter {
		public FormattedBlock Format_block(Block block) {
			var formattedBlock = new FormattedBlock () { Position = block.Position };

			formattedBlock.HexBytes = Format_block_as_hexbytes (block.Bytes);
			formattedBlock.ASCIIBytes = Format_block_as_ASCIIbytes (block.Bytes);

			return formattedBlock;
		}

		private string[] Format_block_as_hexbytes(byte[] bytes) {
			var hexbytes = new string[16];
			for (var i = 0; i < 16; i++) {
				if (i >= bytes.Length)
					hexbytes [i] = "  ";
				else
					hexbytes [i] = bytes [i].ToString ("x2");
			}
			return hexbytes;
		}

		private string[] Format_block_as_ASCIIbytes(byte[] bytes) {
			var asciiBytes = new string[16];
			for (var i = 0; i < 16; i++) {
				if (i >= bytes.Length)
					asciiBytes [i] = ".";
				else
					asciiBytes [i] = bytes [i] >= 32 && bytes [i] <= 250 
						? char.ConvertFromUtf32(bytes[i])
						: ".";
			}
			return asciiBytes;
		}
	}

	class FormattedBlock {
		public long Position;
		public string[] HexBytes;
		public string[] ASCIIBytes;
	}



	class ConsoleProvider {
		public void Print_block(FormattedBlock block) {
			Console.Write ("{0:00000000}: ", block.Position);
			foreach (var hb in block.HexBytes)
				Console.Write ("{0} ", hb);
			foreach (var ab in block.ASCIIBytes)
				Console.Write ("{0}", ab);
			Console.WriteLine ();
		}
	}
}