1 using System.Runtime.InteropServices;
 2     public partial class Form1 : Form
 3     {        
 4         private const int APPCOMMAND_VOLUME_MUTE = 0x80000;
 5         private const int APPCOMMAND_VOLUME_UP = 0xA0000;
 6         private const int APPCOMMAND_VOLUME_DOWN = 0x90000;
 7         private const int WM_APPCOMMAND = 0x319;
 8         [DllImport("user32.dll")]
 9         public static extern IntPtr SendMessageW(IntPtr hWnd, int Msg,
10             IntPtr wParam, IntPtr lParam);
11         public Form1()
12         {
13             InitializeComponent();
14         }
15 
16 
17         private void button1_Click(object sender, EventArgs e)
18         {
19             SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
20                 (IntPtr)APPCOMMAND_VOLUME_MUTE);
21         }
22 
23 
24         private void button2_Click(object sender, EventArgs e)
25         {
26             SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
27                 (IntPtr)APPCOMMAND_VOLUME_DOWN);
28         }
29 
30 
31         private void button3_Click(object sender, EventArgs e)
32         {
33             SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
34                 (IntPtr)APPCOMMAND_VOLUME_UP);
35         }
36 
37     }
38 //button1_click事件让电脑系统静音；button2_click事件实现音量的减少；button3_click事件pc系统音量的添加。