How to: Play a Wave File Using Platform Invoke (Devices)

The following code example illustrates how to use Platform Invoke (PInvoke) to play a wave sound file on a mobile device.

Example

This example code plays a sound file by using PlaySound on the mobile device. This code uses System.Runtime.InteropServices to invoke the PlaySound method of the Compact Framework's CoreDll.DLL.

using System;
using System.Drawing;
using System.Collections;
using System.Windows.Forms;
using System.Data;
using System.Runtime.InteropServices;

namespace MobileSoundPInvoke
{
    public class Form1 : System.Windows.Forms.Form
    {
        private System.Windows.Forms.MainMenu mainMenu1;

        public Form1()
        {
            InitializeComponent();
            PlaySound(".\\sound.wav");
        }

        #region Windows Form Designer generated code
        private void InitializeComponent()
        {
            this.mainMenu1 = new System.Windows.Forms.MainMenu();
            this.Menu = this.mainMenu1;

            this.Text = "Form1";
        }

        #endregion
        protected override void Dispose(bool disposing)
        {
            base.Dispose(disposing);
        }
        static void Main()
        {
            Application.Run(new Form1());
        }
        private enum Flags
        {
            SND_SYNC = 0x0000,
            SND_ASYNC = 0x0001,
            SND_NODEFAULT = 0x0002,
            SND_MEMORY = 0x0004,
            SND_LOOP = 0x0008,
            SND_NOSTOP = 0x0010,
            SND_NOWAIT = 0x00002000,
            SND_ALIAS = 0x00010000,
            SND_ALIAS_ID = 0x00110000,
            SND_FILENAME = 0x00020000,
            SND_RESOURCE = 0x00040004
        }

        [DllImport("CoreDll.DLL", EntryPoint = "PlaySound", SetLastError = true)]
        private extern static int MobilePlaySound(string szSound, IntPtr hMod, int flags);

        public void PlaySound(string fileName)
        {
            MobilePlaySound(fileName, IntPtr.Zero, (int)(Flags.SND_ASYNC | Flags.SND_FILENAME));
        }

    }
}

Compiling the Code

• Create a new C# Smartphone Application project in Visual Studio and call it MobileSoundPInvoke.

• Copy the code from the previous example, and paste it over the Form1.cs file of your MobileSoundPInvoke project in a console application.

Robust Programming

• Make sure the appropriate parameters are passed to the CMobilePlaySound (string szSound, IntPtr hMod, int flags) function, including the path and file name for the .wav file.

Security

For more information about security, see .NET Framework Security.

See Also

Tasks

Platform Invoke Technology Sample

Concepts

Smart Device Samples

How Do I in Smart Device Development

Other Resources

Using Explicit PInvoke in C++ (DllImport Attribute)