A Simple C# WinForm Sound Player Demo

WinFormPlaySound.cs

using System;
using System.Drawing;
using System.IO;
using System.Windows.Forms;

using System.Media;

class BeepSample
{
    static Form form;
    static Button btnPlay;
    static TrackBar tbFreq;
    static bool playing;
    static SoundPlayer player = new SoundPlayer();

    static void Main()
    {
        Application.EnableVisualStyles();
        Application.SetCompatibleTextRenderingDefault(false);
        CreateUI();
        WireUpButtonEvent();
        WireUpTrackbarEvent();
        form.ShowDialog();
        player.Stop();
    }

    public static void CreateUI()
    {
        form = new Form();
        form.Size = new Size(320, 150);
        btnPlay = new Button();
        btnPlay.Location = new Point(form.ClientSize.Width / 2 - 50, 70);
        btnPlay.Size = new Size(100, 25);
        btnPlay.Text = "Play";

        tbFreq = new TrackBar();
        tbFreq.Location = new Point(10, 10);
        tbFreq.Size = new Size(form.ClientSize.Width - 20, 30);
        tbFreq.Minimum = 250;
        tbFreq.Maximum = 3000;

        form.Controls.Add(tbFreq);
        form.Controls.Add(btnPlay);
    }

    public static void WireUpButtonEvent()
    {
        btnPlay.Click += (sndr, args) =>
        {
            if (!playing)
            {
                MemoryStream stream = Play(player, tbFreq.Value);
                player.Stream = stream;
                player.PlayLooping();
                stream.Close();
                btnPlay.Text = "Stop";
                playing = true;
            }
            else
            {
                player.Stop();
                btnPlay.Text = "Play";
                playing = false;
            }
        };
    }

    public static void WireUpTrackbarEvent()
    {
        tbFreq.ValueChanged += (sndr, args) =>
        {
            if (playing)
            {
                player.Stop();
                MemoryStream stream = Play(player, tbFreq.Value);
                player.Stream = stream;
                player.PlayLooping();
                stream.Close();
            }
        };
    }

    // Original code from http://stackoverflow.com/questions/12611982/generate-audio-tone-to-sound-card-in-c-or-c-sharp

    public static MemoryStream Play(SoundPlayer player, int frequency, int msDuration = 1000)
    {
        var soundStream = new MemoryStream();
        BinaryWriter writer = new BinaryWriter(soundStream);
        int samplesPerSecond = 44100;
        int samples = (int)((decimal)samplesPerSecond * msDuration / 1000);

        WriteWavHeader(writer, msDuration, samplesPerSecond);
        GenerateWaveform(writer, frequency, samples, samplesPerSecond);

        soundStream.Seek(0, SeekOrigin.Begin);

        return soundStream;
    }

    private static void WriteWavHeader(BinaryWriter writer, int msDuration, int samplesPerSecond)
    {
        int formatChunkSize = 16;
        int headerSize = 8;
        short formatType = 1;
        short tracks = 1;
        short bitsPerSample = 16;
        short frameSize = (short)(tracks * ((bitsPerSample + 7) / 8));
        int bytesPerSecond = samplesPerSecond * frameSize;
        int waveSize = 4;
        int samples = (int)((decimal)samplesPerSecond * msDuration / 1000);
        int dataChunkSize = samples * frameSize;
        int fileSize = waveSize + headerSize + formatChunkSize + headerSize + dataChunkSize;

        writer.Write(0x46464952);       // = encoding.GetBytes("RIFF")
        writer.Write(fileSize);
        writer.Write(0x45564157);       // = encoding.GetBytes("WAVE")
        writer.Write(0x20746D66);       // = encoding.GetBytes("fmt ")
        writer.Write(formatChunkSize);
        writer.Write(formatType);
        writer.Write(tracks);
        writer.Write(samplesPerSecond);
        writer.Write(bytesPerSecond);
        writer.Write(frameSize);
        writer.Write(bitsPerSample);
        writer.Write(0x61746164);       // = encoding.GetBytes("data")
        writer.Write(dataChunkSize);
    }

    private static void GenerateWaveform(BinaryWriter writer, int frequency, int samples, int samplesPerSecond, int volume = 16383)
    {
        const double TAU = 2 * Math.PI;
        double theta = frequency * TAU / (double)samplesPerSecond;
        // 'volume' is UInt16 with range 0 thru Uint16.MaxValue ( = 65 535)
        // we need 'amp' to have the range of 0 thru Int16.MaxValue ( = 32 767)
        double amp = volume >> 2; // so we simply set amp = volume / 2
        for (int step = 0; step < samples; step++)
        {
            short s = (short)(amp * Math.Sin(theta * (double)step));
            writer.Write(s);
        }
    }
}