C#中調用WIN32 API實現對光碟機的操作

Q:C#中調用WIN32 API實現對光碟機的操作
A:
using System;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.Runtime.InteropServices;
class CDRomControler:Form
{
[DllImport( "winmm.dll", EntryPoint="mciSendStringA", CharSet=CharSet.Ansi )]
public static extern int mciSendString( string lpstrCommand, StringBuilder lpstrReturnString, int uReturnLength, IntPtr hwndCallback );
private Button openButton;
private Button closeButton;
public CDRomControler()
{
this.AutoScaleBaseSize=new Size(5,13);
this.ClientSize=new Size(400,200);
this.Text="C#操作光碟機";

this.openButton=new Button();
openButton.Location=new Point(50,100);
openButton.Size=new Size(100,20);
openButton.TabIndex=1;
openButton.Anchor=AnchorStyles.Bottom|AnchorStyles.Left;
openButton.Text="開啟光碟機";
openButton.Click+=new EventHandler(this.openButton_Click);
this.Controls.Add(this.openButton);

this.closeButton=new Button();
closeButton.Location=new Point(250,100);
closeButton.Size=new Size(100,20);
closeButton.TabIndex=2;
closeButton.Anchor=AnchorStyles.Bottom|AnchorStyles.Right;
closeButton.Text="關閉光碟機";
closeButton.Click+=new EventHandler(this.closeButton_Click);
this.Controls.Add(this.closeButton);
}

private void openButton_Click(object sender, System.EventArgs e)
{
int ret = mciSendString( "set cdaudio door open", null, 0, IntPtr.Zero );
}

private void closeButton_Click(object sender, System.EventArgs e)
{
int ret = mciSendString( "set cdaudio door closed", null, 0, IntPtr.Zero );
}
public static void Main()
{
Application.Run(new CDRomControler()); ;
}
}