wpf 播放MP3没声音 请问是什么原因？
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace MediaPlayTest
{
    /// <summary>
    /// MainWindow.xaml 的交互逻辑
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            mediaPlay();
        }
    
        //MediaPlayer player = null;  方法一
        public void mediaPlay()
        {
            try
            {
                MediaPlayer player = new MediaPlayer();

                player.Open(new Uri("E:\\我的歌声里.mp3", UriKind.Relative));
                VideoDrawing videoDrawing = new VideoDrawing();
                videoDrawing.Rect = new Rect(0, 0, 100, 100);
                videoDrawing.Player = player;
                player.Play();
            }
            catch (Exception e)
            {
                throw e;
            }
        }

        bool flag = true;
        private void Image_MouseLeftButtonDown_1(object sender, MouseButtonEventArgs e)
        {
            //player.Play();
            //if (flag)
            //{
            //    player.Play();
            //    flag = false;