C#中用API实现MP3等音频文件的播放类

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 { 　 /// 　 /// clsMci 的摘要说明。 　 /// 　 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(Unmana gedType.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 = "";

　 TemS

tr = 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

);

　 }

}