HOW TO：在 Windows Form 中非同步地載入音效
更新：2007 年 11 月
下列程式碼範例非同步地從 URL 載入音效，然後在新執行緒上播放。
範例
Imports System
Imports System.Media
Imports System.Windows.Forms
Public Class Form1
Inherits System.Windows.Forms.Form
Friend WithEvents playSoundButton As System.Windows.Forms.Button
Private WithEvents Player As New SoundPlayer
Sub New()
Me.InitializeComponent()
End Sub
Private Sub playSoundButton_Click( _
ByVal sender As System.Object, _
ByVal e As System.EventArgs) _
Handles playSoundButton.Click
' Replace this file name with a valid file name.
Me.Player.SoundLocation = "http://www.tailspintoys.com/sounds/stop.wav"
Me.Player.LoadAsync()
End Sub
Private Sub Player_LoadCompleted( _
ByVal sender As Object, _
ByVal e As _
System.ComponentModel.AsyncCompletedEventArgs) _
Handles Player.LoadCompleted
If Me.Player.IsLoadCompleted Then
Me.Player.Play()
End If
End Sub
'Form overrides dispose to clean up the component list.
<System.Diagnostics.DebuggerNonUserCode()> _
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing AndAlso components IsNot Nothing Then
components.Dispose()
End If
MyBase.Dispose(disposing)
End Sub
'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer
'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
<System.Diagnostics.DebuggerStepThrough()> _
Private Sub InitializeComponent()
Me.playSoundButton = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'playSoundButton
'
Me.playSoundButton.Location = New System.Drawing.Point(105, 107)
Me.playSoundButton.Name = "playSoundButton"
Me.playSoundButton.Size = New System.Drawing.Size(75, 23)
Me.playSoundButton.TabIndex = 0
Me.playSoundButton.Text = "Play Sound"
Me.playSoundButton.UseVisualStyleBackColor = True
'
'Form1
'
Me.AutoScaleDimensions = New System.Drawing.SizeF(6.0!, 13.0!)
Me.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font
Me.ClientSize = New System.Drawing.Size(292, 273)
Me.Controls.Add(Me.playSoundButton)
Me.Name = "Form1"
Me.Text = "Form1"
Me.ResumeLayout(False)
End Sub
<STAThread()> _
Shared Sub Main()
Application.EnableVisualStyles()
Application.Run(New Form1())
End Sub
End Class
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Media;
using System.Windows.Forms;
namespace SoundPlayerLoadAsyncExample
{
public class Form1 : Form
{
private SoundPlayer Player = new SoundPlayer();
public Form1()
{
InitializeComponent();
this.Player.LoadCompleted += new AsyncCompletedEventHandler(Player_LoadCompleted);
}
private void playSoundButton_Click(object sender, EventArgs e)
{
this.LoadAsyncSound();
}
public void LoadAsyncSound()
{
try
{
// Replace this file name with a valid file name.
this.Player.SoundLocation = "http://www.tailspintoys.com/sounds/stop.wav";
this.Player.LoadAsync();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error loading sound");
}
}
// This is the event handler for the LoadCompleted event.
void Player_LoadCompleted(object sender, AsyncCompletedEventArgs e)
{
if (Player.IsLoadCompleted)
{
try
{
this.Player.Play();
}
catch (Exception ex)
{
MessageBox.Show(ex.Message, "Error playing sound");
}
}
}
private Button playSoundButton;
/// <summary>
/// Required designer variable.
/// </summary>
private System.ComponentModel.IContainer components = null;
/// <summary>
/// Clean up any resources being used.
/// </summary>
/// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
protected override void Dispose(bool disposing)
{
if (disposing && (components != null))
{
components.Dispose();
}
base.Dispose(disposing);
}
#region Windows Form Designer generated code
/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{
this.playSoundButton = new System.Windows.Forms.Button();
this.SuspendLayout();
//
// playSoundButton
//
this.playSoundButton.Location = new System.Drawing.Point(106, 112);
this.playSoundButton.Name = "playSoundButton";
this.playSoundButton.Size = new System.Drawing.Size(75, 23);
this.playSoundButton.TabIndex = 0;
this.playSoundButton.Text = "Play Sound";
this.playSoundButton.Click += new System.EventHandler(this.playSoundButton_Click);
//
// Form1
//
this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
this.ClientSize = new System.Drawing.Size(292, 273);
this.Controls.Add(this.playSoundButton);
this.Name = "Form1";
this.Text = "Form1";
this.ResumeLayout(false);
}
#endregion
}
static class Program
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main()
{
Application.EnableVisualStyles();
Application.Run(new Form1());
}
}
}
編譯程式碼
這個範例需要：
System 和 System.Windows.Forms 組件的參考。
您將檔案名稱 "http://www.tailspintoys.com/sounds/stop.wav" 取代為有效的檔案名稱。
如需從 Visual Basic 或 Visual C# 的命令列建置這個範例的詳細資訊，請參閱從命令列建置 (Visual Basic) 或使用 csc.exe 建置命令列。您也可以透過將程式碼貼入新的專案，在 Visual Studio 中建置此範例。
穩固程式設計
檔案作業應放在適當的例外處理區塊內。
下列情形可能會導致例外狀況：
路徑名稱錯誤。例如，它包含無效的字元或只是空白字元 (ArgumentException 類別)。
路徑是唯讀的 (IOException 類別)。
路徑名稱是 Nothing (ArgumentNullException 類別)。
路徑名稱太長 (PathTooLongException 類別)。
路徑無效 (DirectoryNotFoundException 類別)。
路徑只是冒號 ":" (NotSupportedException 類別)。
安全性
不要根據檔案名稱來判斷檔案內容。例如，檔案 Form1.vb 可能不是 Visual Basic 原始程式檔。在應用程式中使用這些資料之前，請先驗證所有輸入值。