C#实现简单播放mp3的方法

/// <summary>
/// 测试
/// </summary>
class testdemo
{
 public void test()
 {
  clsmci cm = new clsmci();
  cm.filename = "alarm.mp3";
  cm.play();
 }
}
/// <summary>
/// clsmci 的摘要说明。
/// </summary>
public class clsmci
{
 public clsmci()
 {
 }
 //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
  {
　　　　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";
     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
    {
    }
  }
 }
 //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
  );
}