C#沒有提供播放MP3等音頻文件的類，要編寫播放MP3等音頻文件程序，必須使用第三方控件或類。本文使用API函數mciSendString，編寫一個播放MP3等音頻文件的類。 具體源碼如下：
一、使用API函數mciSendString構成的媒體播放類。
using System;
using System.Runtime.InteropServices;
using System.Text;
using System.IO ;
namespace clsMCIPlay
{
///
/// clsMci 的摘要說明。
///
public class clsMCI
{
public clsMCI()
{
//
// TODO: 在此處添加構造函數邏輯
//
}
//定義API函數使用的字符串變量
[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;
//定義播放狀態枚舉變量
public enum State
{
mPlaying = 1,
mPuase = 2,
mStop = 3
};
//結構變量
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() ;
//取得播放文件屬性
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("出錯錯誤!");
}
}
}
//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;
}
//總時間
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);
}
}
//當前時間
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、用於測試媒體播放類的簡單代碼：
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
{
///
/// Form1 的摘要說明。
///
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 窗體設計器支持所必需的
//
InitializeComponent();
//
// TODO: 在 InitializeComponent 調用後添加任何構造函數代碼
//
}
///
/// 清理所有正在使用的資源。
///
protected override void Dispose( bool disposing )
{
if( disposing )
{
if (components != null)
{
components.Dispose();
}
}
base.Dispose( disposing );
}
#region Windows 窗體設計器生成的代碼
///
/// 設計器支持所需的方法 - 不要使用代碼編輯器修改
/// 此方法的內容。
///
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
