求助：C#如何实现背景音乐循环播放（有部分代码）

 

using System;

using System.Runtime.InteropServices;

using System.Text;

using System.IO;

using System.Collections.Generic;

namespace love

{

    ///    

    /// clsMci 的摘要说明。   

    ///    

    public class Class1

    {

        public Class1()

        {

            //   

            // 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 (Exception exp)

                {

                    // Log.Error(exp);

                    //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

        );

    }

}

using System;

using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Text;

using System.Windows.Forms;



namespace love

{

    public partial class play : Form

    {

        

        Class1 mp3 = new Class1();

        public play()

        {

            InitializeComponent();

        }



        private void play_Load(object sender, EventArgs e)

        {

            

            Play(Application.StartupPath + @"\mp3\11.mp3");            

           //  Form1 form1 = new Form1();

          //  form1.Show();

        }



        public void Play(string file)

        {

                      

            mp3.FileName = file;

            mp3.play();

        }



       



       

    }

}