如图所示，效果如下：

步骤如下：

新建一个winform窗体，双击界面，进入代码区：

复制（下面代码中命名空间内的代码）到（你的命名空间下），运行。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApp6
{
    public partial class Form1 : Form
    {
        private TextBox textBox1;
        private Button button1;

        public Form1()
        {
            InitializeComponent();
            this.button1 = new System.Windows.Forms.Button();
            this.textBox1 = new System.Windows.Forms.TextBox();
            this.SuspendLayout();
            // 
            // button1
            // 
            this.button1.Location = new System.Drawing.Point(192, 40);
            this.button1.Name = "button1";
            this.button1.Size = new System.Drawing.Size(88, 24);
            this.button1.TabIndex = 0;
            this.button1.Text = "Browse";
            this.button1.Click += new System.EventHandler(this.button1_Click);
            // 
            // textBox1
            // 
            this.textBox1.Location = new System.Drawing.Point(8, 40);
            this.textBox1.Name = "textBox1";
            this.textBox1.Size = new System.Drawing.Size(168, 20);
            this.textBox1.TabIndex = 1;
            this.textBox1.Text = "FIle path";
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(5, 13);
            this.ClientSize = new System.Drawing.Size(292, 266);
            this.Controls.Add(this.textBox1);
            this.Controls.Add(this.button1);
            this.Name = "Form1";
            this.Text = "Platform Invoke WinSound C#";
            this.ResumeLayout(false);
            this.PerformLayout();

        }
        [System.Runtime.InteropServices.DllImport("winmm.DLL", EntryPoint = "PlaySound", SetLastError = true, CharSet = CharSet.Unicode, ThrowOnUnmappableChar = true)]
        private static extern bool PlaySound(string szSound, System.IntPtr hMod, PlaySoundFlags flags);

        [System.Flags]
        public enum PlaySoundFlags : int
        {
            SND_SYNC = 0x0000,
            SND_ASYNC = 0x0001,
            SND_NODEFAULT = 0x0002,
            SND_LOOP = 0x0008,
            SND_NOSTOP = 0x0010,
            SND_NOWAIT = 0x00002000,
            SND_FILENAME = 0x00020000,
            SND_RESOURCE = 0x00040004
        }


        private void Form1_Load(object sender, EventArgs e)
        {

        }

        private void button1_Click(object sender, EventArgs e)
        {
            OpenFileDialog dialog1 = new OpenFileDialog();

            dialog1.Title = "Browse to find sound file to play";
            dialog1.InitialDirectory = @"c:\";
            dialog1.Filter = "Wav Files (*.wav)|*.wav";
            dialog1.FilterIndex = 2;
            dialog1.RestoreDirectory = true;

            if (dialog1.ShowDialog() == DialogResult.OK)
            {
                textBox1.Text = dialog1.FileName;
                PlaySound(dialog1.FileName, new System.IntPtr(), PlaySoundFlags.SND_SYNC);
            }

        }
    }
}