c# 實現電腦系統音量的增加，減少，靜音等。

網上轉載的內容不知道正確與否待本人驗證后，給予測試結果！！！

using System.Runtime.InteropServices;
    public partial class Form1 : Form
    {        
        private const int APPCOMMAND_VOLUME_MUTE = 0x80000;
        private const int APPCOMMAND_VOLUME_UP = 0xA0000;
        private const int APPCOMMAND_VOLUME_DOWN = 0x90000;
        private const int WM_APPCOMMAND = 0x319;
        [DllImport("user32.dll")]
        public static extern IntPtr SendMessageW(IntPtr hWnd, int Msg,
            IntPtr wParam, IntPtr lParam);
        public Form1()
        {
            InitializeComponent();
        }


        private void button1_Click(object sender, EventArgs e)
        {
            SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
                (IntPtr)APPCOMMAND_VOLUME_MUTE);
        }


        private void button2_Click(object sender, EventArgs e)
        {
            SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
                (IntPtr)APPCOMMAND_VOLUME_DOWN);
        }


        private void button3_Click(object sender, EventArgs e)
        {
            SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,
                (IntPtr)APPCOMMAND_VOLUME_UP);
        }

    }
//button1_click事件讓電腦系統靜音；button2_click事件實現音量的減少；button3_click事件pc系統音量的添加。