C# why is Console.ReadKey requiring two keystrokes to work in this code?

Question

I have to press a button twice in order for this code to display the pressed button on the console. Any idea what is wrong with this code?

I tried to trace and debug the code, but the break points at the read and write don't always fire in the while loop when I press a key.

    using System;
    using System.IO;
    namespace ConsoleApplication3
    {
    public class Program
    {
        private interface IReader
        {
            ReadResult Read();
        }

        private interface IWriter
        {
            void Write(char character);
        }

        public class ConsoleWriter : IWriter
        {
            public void Write(char character)
            {
                Console.Write(character);
            }
        }

        public class FileWriter : IWriter, IDispose
        {
            private readonly StreamWriter _streamWriter;

            public FileWriter(StreamWriter streamWriter)
            {
                _streamWriter = streamWriter;
            }

            public void Write(char character)
            {
                _streamWriter.Write(character);
            }

            public void Dispose()
            {
                _streamWriter.Dispose();
            }
        }

        public class ConsoleRead : IReader
        {
            public ReadResult Read()
            {
                return new ReadResult(Console.ReadKey(true).KeyChar, Console.ReadKey(true).Key == ConsoleKey.Escape);
            }
        }

        private static void Main(string[] args)
        {
            IReader reader = new ConsoleRead();
            IWriter writer = new ConsoleWriter();
            Copy(reader, writer);
        }

        private static void Copy(IReader MyReader, IWriter MyWriter)
        {
            while (true)
            {
                var readResult = MyReader.Read();

                if (readResult._shouldQuit)
                    break;
                MyWriter.Write(readResult._readCharacter);
            }
        }

        public interface IDispose
        {
            void Dispose();
        }

        public class ReadResult
        {
            public readonly char _readCharacter;
            public readonly bool _shouldQuit;

            public ReadResult(char ReadCharacter, bool ShouldQuit)
            {
                _readCharacter = ReadCharacter;
                _shouldQuit = ShouldQuit;
            }
        }

    }
}

Answer 1

You're calling ReadKey twice in this function:

public ReadResult Read()
{
    return new ReadResult(Console.ReadKey(true).KeyChar, Console.ReadKey(true).Key == ConsoleKey.Escape);
}

Call it once and store in a variable:

public ReadResult Read()
{
    var temp = Console.ReadKey(true);
    return new ReadResult(temp.KeyChar, temp.Key == ConsoleKey.Escape);
}

Answer 2

You are calling Console.ReadKey() twice, once to get the character and once to determine if escape was pressed.

To have it read only once, change your ConsoleRead class to be:

public class ConsoleRead : IReader
{
    public ReadResult Read()
    {
        var key = Console.ReadKey(true);
        return new ReadResult(key.KeyChar, key.Key == ConsoleKey.Escape);
    }
}

This captures the key pressed, then uses it to create the ReadResult.