o problema C#

[everest4all]

Buna ziua, sunt nou pe forum si as dori sa invat cate ceva despre programare. Vreau sa fac un MP3 player in C# si nu reusesc.
As avea nevoie de un ajutor din partea voastra daca se poate. Mp3-ul are un buton de pornire -play (care e Button2), un buton de
oprire -stop (care e Button1), un buton de incarcare melodie -browse (care e Button3) si o casuta in care este vizualizata melodia
incarcata - (care e textBox1).Singurul lucru care reuseste sa faca este incarcatul melodiei, si vizualizarea ei in textBox. Cand apas
play nu se aude nimic. Aici este codul:

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

namespace mp3
{
public partial class Form1 : Form
{
private string _command;
private bool isopen;
[DllImport("winmm.dll")]
private static extern long mciSendString(string strCommand,StringBuilder strReturn,int iReturnLenght, IntPtr hwndCallBack);



public Form1()
{
InitializeComponent();
}


private void button3_Click(object sender, EventArgs e)
{
OpenFileDialog ofd = new OpenFileDialog();
ofd.InitialDirectory = Environment.SpecialFolder.MyMusic.ToString();
ofd.Filter="mp3 files|*.mp3|All files(*.*)| *.*";
ofd.FilterIndex= 1;
if(ofd.ShowDialog()==DialogResult.OK)
{
this.textBox1.Text = ofd.FileName.ToString();
}
}
public void Play(bool loop)
{
if(isopen)
{
_command="play MediaFile";
if (loop)
_command+="REPEAT";
mciSendString(_command, null, 0, IntPtr.Zero);
}
}
public void OpenPlayer(string sFileName)
{
_command ="open \"" + sFileName + "\"type mpegvideo alias MediaFile";
mciSendString(_command, null, 0, IntPtr.Zero);
isopen=true;
}

public void ClosePlayer()
{
_command="close MediaFile";
mciSendString(_command, null, 0,IntPtr.Zero);
isopen=false;
}
private void button2_Click(object sender,EventArgs e)

{
try
{
this.OpenPlayer(this.textBox1.Text);
this.Play(false);
}
catch(Exception ex )
{
MessageBox.Show(ex. ToString());
}
}
private void button1_Click(object sender, EventArgs e)
{
try
{
this.ClosePlayer();
}
catch(Exception ex )
{
MessageBox.Show(ex.ToString());
}
}
}
}