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Classe SoundPlayer

Controlla la riproduzione di un suono da un file wav.

Spazio dei nomi: System.Media
Assembly: System (in system.dll)

[SerializableAttribute] 
public class SoundPlayer : Component, ISerializable
/** @attribute SerializableAttribute() */ 
public class SoundPlayer extends Component implements ISerializable
SerializableAttribute 
public class SoundPlayer extends Component implements ISerializable
Non applicabile.

La classe SoundPlayer fornisce una semplice interfaccia per il caricamento e la riproduzione di un file wav. La classe SoundPlayer supporta il caricamento di un file wav da un percorso di file, da un URL, da una classe Stream contenente un file wav o da una risorsa incorporata contenente un file wav.

Per riprodurre un suono mediante la classe SoundPlayer, configurare una classe SoundPlayer con un percorso al file wav e chiamare uno dei metodi di riproduzione. È possibile identificare il file wav da riprodurre utilizzando uno dei costruttori o impostando la proprietà SoundLocation o Stream. È possibile caricare il file prima della riproduzione utilizzando uno dei metodi di caricamento oppure è possibile rinviare il caricamento fino alla chiamata di uno dei metodi di riproduzione. È necessario che una classe SoundPlayer configurata per caricare un file wav da una classe Stream o da un URL carichi il file wav in memoria prima dell'inizio della riproduzione.

È possibile caricare o riprodurre un file wav in modo sincrono o asincrono. Se si chiama un metodo di riproduzione o di caricamento sincrono, il thread chiamante attenderà fino alla restituzione del metodo, che potrebbe provocare l'interruzione della visualizzazione e di altri eventi. La chiamata a un metodo di riproduzione o di caricamento asincrono consentirà al thread chiamante di continuare senza interruzione. Per ulteriori informazioni sulle chiamate ai metodi asincroni, vedere Procedura: eseguire un'operazione in background.

Dopo che una classe SoundPlayer ha terminato di caricare un file wav, genera l'evento LoadCompleted. È possibile esaminare la classe AsyncCompletedEventArgs nel gestore eventi per determinare l'esito del caricamento. L'evento SoundLocationChanged viene generato quando l'origine audio viene impostata su un nuovo percorso di file o URL. L'evento StreamChanged viene generato quando l'origine audio viene impostata su una nuova classe Stream. Per ulteriori informazioni sulla gestione di eventi, vedere Utilizzo degli eventi.

Per ulteriori informazioni su SoundPlayer, vedere Cenni preliminari sulla classe SoundPlayer.

Nel codice di esempio riportato di seguito viene illustrato l'utilizzo della classe SoundPlayer per la riproduzione di file wav da un percorso locale o da un URI (Uniform Resource Identifier).


using System;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics;
using System.Drawing;
using System.Media;
using System.Windows.Forms;

namespace SoundApiExample
{
    public class SoundTestForm : System.Windows.Forms.Form
    {
        private System.Windows.Forms.Label label1;
        private System.Windows.Forms.TextBox filepathTextbox;        
        private System.Windows.Forms.Button playOnceSyncButton;
        private System.Windows.Forms.Button playOnceAsyncButton;
        private System.Windows.Forms.Button playLoopAsyncButton;
        private System.Windows.Forms.Button selectFileButton;
        
        private System.Windows.Forms.Button stopButton;
        private System.Windows.Forms.StatusBar statusBar;
        private System.Windows.Forms.Button loadSyncButton;
        private System.Windows.Forms.Button loadAsyncButton;        
        private SoundPlayer player;

        public SoundTestForm()
        {
            // Initialize Forms Designer generated code.
            InitializeComponent();
			
            // Disable playback controls until a valid .wav file 
            // is selected.
            EnablePlaybackControls(false);

            // Set up the status bar and other controls.
            InitializeControls();

            // Set up the SoundPlayer object.
            InitializeSound();
        }

        // Sets up the status bar and other controls.
        private void InitializeControls()
        {
            // Set up the status bar.
            StatusBarPanel panel = new StatusBarPanel();
            panel.BorderStyle = StatusBarPanelBorderStyle.Sunken;
            panel.Text = "Ready.";
            panel.AutoSize = StatusBarPanelAutoSize.Spring;
            this.statusBar.ShowPanels = true;
            this.statusBar.Panels.Add(panel);
        }

        // Sets up the SoundPlayer object.
        private void InitializeSound()
        {
            // Create an instance of the SoundPlayer class.
            player = new SoundPlayer();

            // Listen for the LoadCompleted event.
            player.LoadCompleted += new AsyncCompletedEventHandler(player_LoadCompleted);

            // Listen for the SoundLocationChanged event.
            player.SoundLocationChanged += new EventHandler(player_LocationChanged);
        }

        private void selectFileButton_Click(object sender, 
            System.EventArgs e)
        {
            // Create a new OpenFileDialog.
            OpenFileDialog dlg = new OpenFileDialog();

            // Make sure the dialog checks for existence of the 
            // selected file.
            dlg.CheckFileExists = true;

            // Allow selection of .wav files only.
            dlg.Filter = "WAV files (*.wav)|*.wav";
            dlg.DefaultExt = ".wav";

            // Activate the file selection dialog.
            if (dlg.ShowDialog() == DialogResult.OK)
            {
                // Get the selected file's path from the dialog.
                this.filepathTextbox.Text = dlg.FileName;

                // Assign the selected file's path to 
                // the SoundPlayer object.  
                player.SoundLocation = filepathTextbox.Text;
            }
        }

        // Convenience method for setting message text in 
        // the status bar.
        private void ReportStatus(string statusMessage)
        {
            // If the caller passed in a message...
            if ((statusMessage != null) && (statusMessage != String.Empty))
            {
                // ...post the caller's message to the status bar.
                this.statusBar.Panels[0].Text = statusMessage;
            }
        }
        
        // Enables and disables play controls.
        private void EnablePlaybackControls(bool enabled)
        {   
            this.playOnceSyncButton.Enabled = enabled;
            this.playOnceAsyncButton.Enabled = enabled;
            this.playLoopAsyncButton.Enabled = enabled;
            this.stopButton.Enabled = enabled;
        }
    
        private void filepathTextbox_TextChanged(object sender, 
            EventArgs e)
        {
            // Disable playback controls until the new .wav is loaded.
            EnablePlaybackControls(false);
        }

        private void loadSyncButton_Click(object sender, 
            System.EventArgs e)
        {   
            // Disable playback controls until the .wav is 
            // successfully loaded. The LoadCompleted event 
            // handler will enable them.
            EnablePlaybackControls(false);

            try
            {
                // Assign the selected file's path to 
                // the SoundPlayer object.  
                player.SoundLocation = filepathTextbox.Text;

                // Load the .wav file.
                player.Load();
            }
            catch (Exception ex)
            {
                ReportStatus(ex.Message);
            }
        }

        private void loadAsyncButton_Click(System.Object sender, 
            System.EventArgs e)
        {
            // Disable playback controls until the .wav is 
            // successfully loaded. The LoadCompleted event 
            // handler will enable them.
            EnablePlaybackControls(false);

            try
            {
                // Assign the selected file's path to 
                // the SoundPlayer object.  
                player.SoundLocation = this.filepathTextbox.Text;

                // Load the .wav file.
                player.LoadAsync();
            }
            catch (Exception ex)
            {
                ReportStatus(ex.Message);
            }
        }

        // Synchronously plays the selected .wav file once.
        // If the file is large, UI response will be visibly 
        // affected.
        private void playOnceSyncButton_Click(object sender, 
            System.EventArgs e)
        {	
            ReportStatus("Playing .wav file synchronously.");
            player.PlaySync();
            ReportStatus("Finished playing .wav file synchronously.");
        }

        // Asynchronously plays the selected .wav file once.
        private void playOnceAsyncButton_Click(object sender, 
            System.EventArgs e)
        {
            ReportStatus("Playing .wav file asynchronously.");
            player.Play();
        }

        // Asynchronously plays the selected .wav file until the user
        // clicks the Stop button.
        private void playLoopAsyncButton_Click(object sender, 
            System.EventArgs e)
        {
            ReportStatus("Looping .wav file asynchronously.");
            player.PlayLooping();
        }

        // Stops the currently playing .wav file, if any.
        private void stopButton_Click(System.Object sender,
            System.EventArgs e)
        {	
            player.Stop();
            ReportStatus("Stopped by user.");
        }

        // Handler for the LoadCompleted event.
        private void player_LoadCompleted(object sender, 
            AsyncCompletedEventArgs e)
        {   
            string message = String.Format("LoadCompleted: {0}", 
                this.filepathTextbox.Text);
            ReportStatus(message);
            EnablePlaybackControls(true);
        }

        // Handler for the SoundLocationChanged event.
        private void player_LocationChanged(object sender, EventArgs e)
        {   
            string message = String.Format("SoundLocationChanged: {0}", 
                player.SoundLocation);
            ReportStatus(message);
        }

        #region Windows Form Designer generated code
        private void InitializeComponent()
        {
            this.filepathTextbox = new System.Windows.Forms.TextBox();
            this.selectFileButton = new System.Windows.Forms.Button();
            this.label1 = new System.Windows.Forms.Label();
            this.loadSyncButton = new System.Windows.Forms.Button();
            this.playOnceSyncButton = new System.Windows.Forms.Button();
            this.playOnceAsyncButton = new System.Windows.Forms.Button();
            this.stopButton = new System.Windows.Forms.Button();
            this.playLoopAsyncButton = new System.Windows.Forms.Button();
            this.statusBar = new System.Windows.Forms.StatusBar();
            this.loadAsyncButton = new System.Windows.Forms.Button();
            this.SuspendLayout();
            // 
            // filepathTextbox
            // 
            this.filepathTextbox.Anchor = ((System.Windows.Forms.AnchorStyles)(((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Left) | System.Windows.Forms.AnchorStyles.Right)));
            this.filepathTextbox.Location = new System.Drawing.Point(7, 25);
            this.filepathTextbox.Name = "filepathTextbox";
            this.filepathTextbox.Size = new System.Drawing.Size(263, 20);
            this.filepathTextbox.TabIndex = 1;
            this.filepathTextbox.Text = "";
            this.filepathTextbox.TextChanged += new System.EventHandler(this.filepathTextbox_TextChanged);
            // 
            // selectFileButton
            // 
            this.selectFileButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Top | System.Windows.Forms.AnchorStyles.Right)));
            this.selectFileButton.Location = new System.Drawing.Point(276, 25);
            this.selectFileButton.Name = "selectFileButton";
            this.selectFileButton.Size = new System.Drawing.Size(23, 21);
            this.selectFileButton.TabIndex = 2;
            this.selectFileButton.Text = "...";
            this.selectFileButton.Click += new System.EventHandler(this.selectFileButton_Click);
            // 
            // label1
            // 
            this.label1.Location = new System.Drawing.Point(7, 7);
            this.label1.Name = "label1";
            this.label1.Size = new System.Drawing.Size(145, 17);
            this.label1.TabIndex = 3;
            this.label1.Text = ".wav path or URL:";
            // 
            // loadSyncButton
            // 
            this.loadSyncButton.Location = new System.Drawing.Point(7, 53);
            this.loadSyncButton.Name = "loadSyncButton";
            this.loadSyncButton.Size = new System.Drawing.Size(142, 23);
            this.loadSyncButton.TabIndex = 4;
            this.loadSyncButton.Text = "Load Synchronously";
            this.loadSyncButton.Click += new System.EventHandler(this.loadSyncButton_Click);
            // 
            // playOnceSyncButton
            // 
            this.playOnceSyncButton.Location = new System.Drawing.Point(7, 86);
            this.playOnceSyncButton.Name = "playOnceSyncButton";
            this.playOnceSyncButton.Size = new System.Drawing.Size(142, 23);
            this.playOnceSyncButton.TabIndex = 5;
            this.playOnceSyncButton.Text = "Play Once Synchronously";
            this.playOnceSyncButton.Click += new System.EventHandler(this.playOnceSyncButton_Click);
            // 
            // playOnceAsyncButton
            // 
            this.playOnceAsyncButton.Location = new System.Drawing.Point(149, 86);
            this.playOnceAsyncButton.Name = "playOnceAsyncButton";
            this.playOnceAsyncButton.Size = new System.Drawing.Size(147, 23);
            this.playOnceAsyncButton.TabIndex = 6;
            this.playOnceAsyncButton.Text = "Play Once Asynchronously";
            this.playOnceAsyncButton.Click += new System.EventHandler(this.playOnceAsyncButton_Click);
            // 
            // stopButton
            // 
            this.stopButton.Location = new System.Drawing.Point(149, 109);
            this.stopButton.Name = "stopButton";
            this.stopButton.Size = new System.Drawing.Size(147, 23);
            this.stopButton.TabIndex = 7;
            this.stopButton.Text = "Stop";
            this.stopButton.Click += new System.EventHandler(this.stopButton_Click);
            // 
            // playLoopAsyncButton
            // 
            this.playLoopAsyncButton.Location = new System.Drawing.Point(7, 109);
            this.playLoopAsyncButton.Name = "playLoopAsyncButton";
            this.playLoopAsyncButton.Size = new System.Drawing.Size(142, 23);
            this.playLoopAsyncButton.TabIndex = 8;
            this.playLoopAsyncButton.Text = "Loop Asynchronously";
            this.playLoopAsyncButton.Click += new System.EventHandler(this.playLoopAsyncButton_Click);
            // 
            // statusBar
            // 
            this.statusBar.Location = new System.Drawing.Point(0, 146);
            this.statusBar.Name = "statusBar";
            this.statusBar.Size = new System.Drawing.Size(306, 22);
            this.statusBar.SizingGrip = false;
            this.statusBar.TabIndex = 9;
            this.statusBar.Text = "(no status)";
            // 
            // loadAsyncButton
            // 
            this.loadAsyncButton.Location = new System.Drawing.Point(149, 53);
            this.loadAsyncButton.Name = "loadAsyncButton";
            this.loadAsyncButton.Size = new System.Drawing.Size(147, 23);
            this.loadAsyncButton.TabIndex = 10;
            this.loadAsyncButton.Text = "Load Asynchronously";
            this.loadAsyncButton.Click += new System.EventHandler(this.loadAsyncButton_Click);
            // 
            // SoundTestForm
            // 
            this.ClientSize = new System.Drawing.Size(306, 168);
            this.Controls.Add(this.loadAsyncButton);
            this.Controls.Add(this.statusBar);
            this.Controls.Add(this.playLoopAsyncButton);
            this.Controls.Add(this.stopButton);
            this.Controls.Add(this.playOnceAsyncButton);
            this.Controls.Add(this.playOnceSyncButton);
            this.Controls.Add(this.loadSyncButton);
            this.Controls.Add(this.label1);
            this.Controls.Add(this.selectFileButton);
            this.Controls.Add(this.filepathTextbox);
            this.MinimumSize = new System.Drawing.Size(310, 165);
            this.Name = "SoundTestForm";
            this.SizeGripStyle = System.Windows.Forms.SizeGripStyle.Show;
            this.Text = "Sound API Test Form";
            this.ResumeLayout(false);

        }
        #endregion
        
        [STAThread]
        static void Main()
        {
            Application.Run(new SoundTestForm());
        }
    }
}

I membri statici pubblici (Shared in Visual Basic) di questo tipo sono validi per le operazioni multithreading. I membri di istanza non sono garantiti come thread safe.

Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile per Pocket PC, Windows Mobile per Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

Microsoft .NET Framework 3.0 è supportato in Windows Vista, Microsoft Windows XP SP2 e Windows Server 2003 SP1.

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