c# 系统音量的控制

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


namespace WindowsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();            
        }
        
        [DllImport("user32.dll", EntryPoint = "SendMessageA")]
        public static extern int SendMessage(IntPtr handle, int wMsg, int wParam, int lParam);   

        private const int WM_APPCOMMAND = 0x319;
        private const int APPCOMMAND_VOLUME_UP = 10;
        private const int APPCOMMAND_VOLUME_DOWN = 9;
        private const int APPCOMMAND_VOLUME_MUTE = 8;

        private void button1_Click(object sender, EventArgs e)
        {
            SendMessage(Handle, WM_APPCOMMAND, 0x30292, APPCOMMAND_VOLUME_UP * 0x10000);
            
        }

        private void button2_Click(object sender, EventArgs e)
        {
            SendMessage(Handle, WM_APPCOMMAND, 0x30292, APPCOMMAND_VOLUME_DOWN * 0x10000);
        }

        private void button3_Click(object sender, EventArgs e)
        {
            SendMessage(Handle, WM_APPCOMMAND, 0x200EB0, APPCOMMAND_VOLUME_MUTE * 0x10000);
        }


    }
}

三个按钮分别为增加音量,减少音量,静音

以下代码捕捉系统消息,改变系统声音音量

protected override void WndProc(ref Message m)//监视Windows消息
        {
            const int WM_APPCOMMAND = 0x319;

            switch (m.Msg)
            {
                case WM_APPCOMMAND:
                    {
                        MessageBox.Show(m.ToString());
                    }
                break;
            }
            
            base.WndProc(ref m); //将系统消息传递自父类的WndProc
        }