C#中用API实现MP3等音频文件的播放类

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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 ); 　 } }