制作音乐播放器（C#）

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.IO;  //Path类用到
using System.Media;    //SoundPlayer命名空间
namespace player
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        List<string> listsongs = new List<string>();   //用来存储音乐文件的全路径
        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog ofd = new OpenFileDialog();
            ofd.Title = "请选择音乐文件";      //打开对话框的标题
            ofd.InitialDirectory = @"F:\music";    //设置打开对话框的初始设置目录
            ofd.Multiselect = true; //设置多选
            ofd.Filter = @"音乐文件|*.mp3||*.wav|所有文件|*.*";    //设置文件格式筛选
            ofd.ShowDialog();   //显示打开对话框
            string[] pa_th = ofd.FileNames;       //获得在文件夹中选择的所有文件的全路径
            for (int i = 0; i < pa_th.Length;i++ )
            {
                listBox1.Items.Add(Path.GetFileName(pa_th[i]));  //将音乐文件的文件名加载到listBox中
                listsongs.Add(pa_th[i]);    //将音乐文件的全路径存储到泛型集合中
            }
        }
        SoundPlayer sp = new SoundPlayer();
        private void listBox1_DoubleClick(object sender, EventArgs e)
        {
            SoundPlayer sp = new SoundPlayer();
            sp.SoundLocation = listsongs[listBox1.SelectedIndex];
            sp.Play();
        }

 private void button2_Click(object sender, EventArgs e)
        {
            int index = listBox1.SelectedIndex; //获得当前选中歌曲的索引
            index--;

            if (index <0)
            {
                index = listBox1.Items.Count-1;
            }
            listBox1.SelectedIndex = index; //将改变后的索引重新赋值给我当前选中项的索引
            sp.SoundLocation = listsongs[index];
            sp.Play();
        }

        private void button3_Click(object sender, EventArgs e)
        {
              int index = listBox1.SelectedIndex; //获得当前选中歌曲的索引
            index++;

            if (index==listBox1.Items.Count)
            {
                index = 0;
            }
            listBox1.SelectedIndex = index; //将改变后的索引重新赋值给我当前选中项的索引
            sp.SoundLocation = listsongs[index];
            sp.Play();
        }

        private void Form1_DragEnter(object sender, DragEventArgs e)
        {
            if (e.Data.GetDataPresent(DataFormats.FileDrop)) e.Effect = DragDropEffects.Link;
            else e.Effect = DragDropEffects.None;
        }

        private void Form1_DragDrop(object sender, DragEventArgs e)
        {
            string[] filePath = (string[])e.Data.GetData(DataFormats.FileDrop);
            foreach (string file in filePath)
            {
                //file就是单个文件路径
                SoundPlayer sp = new SoundPlayer();
                sp.SoundLocation = file;
                sp.Play();
              //  MessageBox.Show(file);
            }
        }

        private void button4_Click(object sender, EventArgs e)
        {
            SoundPlayer sp = new SoundPlayer();
            if (listBox1.SelectedIndex > 0)
                sp.SoundLocation = listsongs[listBox1.SelectedIndex];
            sp.Play();
        }

        private void groupBox2_Enter(object sender, EventArgs e)
        {

        }

        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
        {

        }

        private void Form1_Load(object sender, EventArgs e)
        {

        }
    }
}