C#中用API实现MP3等音频文件的播放类转

C#没有提供播放MP3等音频文件的类，要编写播放MP3等音频文件程序，必须使用第三方控件或类。本文使用API函数mciSendString，编写一个播放MP3等音频文件的类。

具体源码如下：

一、使用API函数mciSendString构成的媒体播放类。

using System;

using System.Runtime.InteropServices;

using System.Text;

using System.IO ;

namespace clsMCIPlay

{

　 /// <summary>

　 /// clsMci 的摘要说明。

　 /// </summary>

　 public class clsMCI

　 {

public clsMCI()

{

　 //

　 // TODO: 在此处添加构造函数逻辑

　 //

}

//定义API函数使用的字符串变量

[MarshalAs(UnmanagedType.ByValTStr,SizeConst=260)]

private string Name = "" ;

[MarshalAs(UnmanagedType.ByValTStr,SizeConst=128)]

private string durLength = "" ;

[MarshalAs(UnmanagedType.LPTStr,SizeConst=128)]

private string TemStr ="";

int ilong;

//定义播放状态枚举变量

public enum State

{

　 mPlaying = 1,

　 mPuase = 2,

　 mStop = 3

};

//结构变量

public struct structMCI

{

　 public bool bMut;

　 public int iDur;

　 public int iPos;

　 public int iVol;

　 public int iBal;

　 public string iName;

　 public State state;

};

public structMCI mc =new structMCI() ;

//取得播放文件属性

public string FileName

{

　 get

　 {

return mc.iName;

　 }

　 set

　 {

//ASCIIEncoding asc = new ASCIIEncoding();

try

{

　 TemStr ="";

　 TemStr = TemStr.PadLeft(127,Convert.ToChar(" "));

　 Name = Name.PadLeft(260,Convert.ToChar(" ")) ;

　 mc.iName = value;

　 ilong = APIClass.GetShortPathName(mc.iName,Name, Name.Length);

　 Name = GetCurrPath(Name);

　 //Name = "open " + Convert.ToChar(34) + Name + Convert.ToChar(34) + " alias media";

　 Name = "open " + Convert.ToChar(34) + Name + Convert.ToChar(34) + " alias media";

　 ilong = APIClass.mciSendString("close all", TemStr, TemStr.Length , 0);

　 ilong = APIClass.mciSendString( Name, TemStr, TemStr.Length, 0);

　 ilong = APIClass.mciSendString("set media time format milliseconds", TemStr, TemStr.Length , 0);

　 mc.state = State.mStop;

}

catch

{

　 MessageBox.Show("出错错误!");

}

　 }

}

//播放

public void play()

{

　 TemStr = "";

　 TemStr = TemStr.PadLeft(127,Convert.ToChar(" "));

　 APIClass.mciSendString("play media", TemStr, TemStr.Length , 0);

　 mc.state = State.mPlaying ;

}

//停止

public void StopT()

{

　 TemStr = "";

　 TemStr = TemStr.PadLeft(128,Convert.ToChar(" "));

　 ilong = APIClass.mciSendString("close media", TemStr, 128, 0);

　 ilong = APIClass.mciSendString("close all", TemStr, 128, 0);

　 mc.state = State.mStop ;

}

public void Puase()

{

　 TemStr = "";

　 TemStr = TemStr.PadLeft(128,Convert.ToChar(" "));

　 ilong = APIClass.mciSendString("pause media", TemStr, TemStr.Length, 0);

　 mc.state = State.mPuase ;

}

private string GetCurrPath(string name)

{

　 if(name.Length <1) return "";

　 name = name.Trim();

　 name = name.Substring(0,name.Length-1);

　 return name;

}

//总时间

public int Duration

{

　 get

　 {

durLength = "";

durLength = durLength.PadLeft(128,Convert.ToChar(" ")) ;

APIClass.mciSendString("status media length", durLength, durLength.Length, 0);

durLength = durLength.Trim();

if(durLength == "") return 0;

return (int)(Convert.ToDouble(durLength) / 1000f);

　 }

}

//当前时间

public int CurrentPosition

{

　 get

　 {

durLength = "";

durLength = durLength.PadLeft(128,Convert.ToChar(" ")) ;

APIClass.mciSendString("status media position", durLength, durLength.Length, 0);

mc.iPos = (int)(Convert.ToDouble(durLength) / 1000f);

return mc.iPos;

　 }

}

　 }

　 public class APIClass

　 {

[DllImport("kernel32.dll", CharSet = CharSet.Auto)]

public static extern int GetShortPathName (

　 string lpszLongPath,

　 string shortFile,

　 int cchBuffer

);

[DllImport("winmm.dll", EntryPoint="mciSendString", CharSet = CharSet.Auto)]

public static extern int mciSendString (

　 string lpstrCommand,

　 string lpstrReturnString,

　 int uReturnLength,

　 int hwndCallback

);

　 }

}

二、用于测试媒体播放类的简单代码：

using System;

using System.Drawing;

using System.Collections;

using System.ComponentModel;

using System.Windows.Forms;

using System.Data;

using System.Runtime.InteropServices;

using System.Text;

using System.IO ;

using clsMCIPlay;

namespace MCIPlay

{

　 /// <summary>

　 /// Form1 的摘要说明。

　 /// </summary>

　 public class Form1 : System.Windows.Forms.Form

　 {

private System.ComponentModel.IContainer components;

private System.Windows.Forms.Timer timer1;

private System.Windows.Forms.Button Play;

private System.Windows.Forms.Button Stop;

private System.Windows.Forms.Button Puase;

private System.Windows.Forms.Label PlayFileName;

private System.Windows.Forms.Label Duration;

private System.Windows.Forms.Label CurrentPosition;

private System.Windows.Forms.OpenFileDialog openFileDialog1;

private System.Windows.Forms.Button BrowserFile;

clsMCI mp = new clsMCI();

public Form1()

{

　 //

　 // Windows 窗体设计器支持所必需的

　 //

　 InitializeComponent();

　 //

　 // TODO: 在 InitializeComponent 调用后添加任何构造函数代码

　 //

}

/// <summary>

/// 清理所有正在使用的资源。

/// </summary>

protected override void Dispose( bool disposing )

{

　 if( disposing )

　 {

if (components != null)

{

　 components.Dispose();

}

　 }

　 base.Dispose( disposing );

}

#region Windows 窗体设计器生成的代码

/// <summary>

/// 设计器支持所需的方法 - 不要使用代码编辑器修改

/// 此方法的内容。

/// </summary>

private void InitializeComponent()

{

　 this.components = new System.ComponentModel.Container();

　 this.Play = new System.Windows.Forms.Button();

　 this.PlayFileName = new System.Windows.Forms.Label();

　 this.Duration = new System.Windows.Forms.Label();

　 this.Stop = new System.Windows.Forms.Button();

　 this.Puase = new System.Windows.Forms.Button();

　 this.CurrentPosition = new System.Windows.Forms.Label();

　 this.timer1 = new System.Windows.Forms.Timer(this.components);

　 this.openFileDialog1 = new System.Windows.Forms.OpenFileDialog();

　 this.BrowserFile = new System.Windows.Forms.Button();

　 this.SuspendLayout();

　 //

　 // Play

　 //

　 this.Play.Location = new System.Drawing.Point(102, 243);

　 this.Play.Name = "Play";

　 this.Play.Size = new System.Drawing.Size(78, 24);

　 this.Play.TabIndex = 0;

　 this.Play.Text = "Play";

　 this.Play.Click += new System.EventHandler(this.Play_Click);

　 //

　 // PlayFileName

　 //

　 this.PlayFileName.AutoSize = true;

　 this.PlayFileName.Location = new System.Drawing.Point(12, 15);

　 this.PlayFileName.Name = "PlayFileName";

　 this.PlayFileName.Size = new System.Drawing.Size(0, 17);

　 this.PlayFileName.TabIndex = 1;

　 //

　 // Duration

　 //

　 this.Duration.AutoSize = true;

　 this.Duration.Location = new System.Drawing.Point(15, 51);

　 this.Duration.Name = "Duration";

　 this.Duration.Size = new System.Drawing.Size(0, 17);

　 this.Duration.TabIndex = 2;

　 //

　 // Stop

　 //

　 this.Stop.Location = new System.Drawing.Point(282, 243);

　 this.Stop.Name = "Stop";

　 this.Stop.Size = new System.Drawing.Size(81, 24);

　 this.Stop.TabIndex = 3;

　 this.Stop.Text = "Stop";

　 this.Stop.Click += new System.EventHandler(this.Stop_Click);

　 //

　 // Puase

　 //

　 this.Puase.Location = new System.Drawing.Point(198, 243);

　 this.Puase.Name = "Puase";

　 this.Puase.Size = new System.Drawing.Size(72, 24);

　 this.Puase.TabIndex = 4;

　 this.Puase.Text = "Puase";

　 this.Puase.Click += new System.EventHandler(this.Puase_Click);

　 //

　 // CurrentPosition

　 //

　 this.CurrentPosition.AutoSize = true;

　 this.CurrentPosition.Location = new System.Drawing.Point(15, 87);

　 this.CurrentPosition.Name = "CurrentPosition";

　 this.CurrentPosition.Size = new System.Drawing.Size(0, 17);

　 this.CurrentPosition.TabIndex = 5;

　 //

　 // timer1

　 //

　 this.timer1.Enabled = true;

　 this.timer1.Interval = 1000;

　 this.timer1.Tick += new System.EventHandler(this.timer1_Tick);

　 //

　 // BrowserFile

　 //

　 this.BrowserFile.Location = new System.Drawing.Point(312, 165);

　 this.BrowserFile.Name = "BrowserFile";

　 this.BrowserFile.Size = new System.Drawing.Size(87, 24);

　 this.BrowserFile.TabIndex = 6;

　 this.BrowserFile.Text = "SelectFile";

　 this.BrowserFile.Click += new System.EventHandler(this.BrowserFile_Click);

　 //

　 // Form1

　 //

　 this.AutoScaleBaseSize = new System.Drawing.Size(6, 14);

　 this.ClientSize = new System.Drawing.Size(433, 287);

　 this.Controls.Add(this.BrowserFile);

　 this.Controls.Add(this.CurrentPosition);

　 this.Controls.Add(this.Puase);

　 this.Controls.Add(this.Stop);

　 this.Controls.Add(this.Duration);

　 this.Controls.Add(this.PlayFileName);

　 this.Controls.Add(this.Play);

　 this.Name = "Form1";

　 this.Text = "Form1";

　 this.ResumeLayout(false);

}

#endregion

/// <summary>

/// 应用程序的主入口点。

/// </summary>

[STAThread]

static void Main()

{

　 Application.Run(new Form1());

}

//选择MP3文件播放

private void Play_Click(object sender, System.EventArgs e)

{

　 try

　 {

mp.play();

　 }

　 catch

　 {

MessageBox.Show("出错错误!");

　 }

}

//暂停播放

private void Puase_Click(object sender, System.EventArgs e)

{

　 try

　 {

mp.Puase();

　 }

　 catch

　 {

MessageBox.Show("出错错误!");

　 }

}

//停止播放

private void Stop_Click(object sender, System.EventArgs e)

{

　 try

　 {

mp.StopT();

　 }

　 catch

　 {

MessageBox.Show("出错错误!");

　 }

}

//每秒显示一次播放进度

private void timer1_Tick(object sender, System.EventArgs e)

{

　 CurrentPosition.Text = mp.CurrentPosition.ToString();

}

//浏览文件

private void BrowserFile_Click(object sender, System.EventArgs e)

{

　 try

　 {

openFileDialog1.Filter = "*.mp3|*.mp3";

openFileDialog1.FileName = "";

if(openFileDialog1.ShowDialog() == DialogResult.OK)

{

　 mp.FileName = openFileDialog1.FileName ;

　 PlayFileName.Text = openFileDialog1.FileName ;

　 Duration.Text = mp.Duration.ToString() ;

}

　 }

　 catch

　 {

MessageBox.Show("出错错误!");

　 }

}

　 }

}

本程序在.net 2003 、win XP SP1下编译通过。