var filePath = Path.Combine(System.Windows.Forms.Application.StartupPath, @"sound\歌曲.wav");

            //播放系统声音：多线程可正常播放
            System.Media.SystemSounds.Beep.Play();
            Thread.Sleep(1000);

            //播放wav/mp3声音文件：多线程可正常播放
            MySoundPlayer.PlayMusic(filePath);
            MySoundPlayer.StopMusic(filePath);

            //播放wav/mp3声音文件：多线程播放无效，单线程有效
            System.Windows.Media.MediaPlayer mr = new System.Windows.Media.MediaPlayer();
            mr.Open(new Uri(filePath));
            mr.Play();
            mr.Close();

    public class MySoundPlayer
    {

        public static uint SND_ASYNC = 0x0001;
        public static uint SND_FILENAME = 0x00020000;
        [DllImport("winmm.dll")]
        public static extern uint mciSendString(string lpstrCommand, string lpstrReturnString, uint uReturnLength, uint hWndCallback);

        public static void PlayNmusinc(string path)
        {
            mciSendString(@"close temp_alias", null, 0, 0);
            mciSendString(@"open """ + path + @""" alias temp_alias", null, 0, 0);
            mciSendString("play temp_alias repeat", null, 0, 0);
        }

        /// <summary>
        /// 播放音乐文件(重复)
        /// </summary>
        /// <param name="p_FileName">音乐文件名称</param>
        public static void PlayMusic_Repeat(string p_FileName)
        {
            try
            {
                mciSendString(@"close temp_music", " ", 0, 0);
                mciSendString(@"open " + p_FileName + " alias temp_music", " ", 0, 0);
                mciSendString(@"play temp_music repeat", " ", 0, 0);
            }
            catch
            { }
        }

        /// <summary>
        /// 播放音乐文件
        /// </summary>
        /// <param name="p_FileName">音乐文件名称</param>
        public static void PlayMusic(string p_FileName)
        {
            try
            {
                mciSendString(@"close temp_music", " ", 0, 0);
                //mciSendString(@"open " + p_FileName + " alias temp_music", " ", 0, 0);
                mciSendString(@"open """ + p_FileName + @""" alias temp_music", null, 0, 0);
                mciSendString(@"play temp_music", " ", 0, 0);
            }
            catch
            { }
        }

        /// <summary>
        /// 停止当前音乐播放
        /// </summary>
        /// <param name="p_FileName">音乐文件名称</param>
        public static void StopMusic(string p_FileName)
        {
            try
            {
                mciSendString(@"close " + p_FileName, " ", 0, 0);
            }
            catch { }
        }

    }