How to change the System Volume programmatically

Question

Hai Every one ...I want to change the System volume .I am using fallowing code......
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Runtime.InteropServices;
namespace shaped_form
{
class VolumeChange
{
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);
private void btnMute_Click(object sender, EventArgs e)
{
SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,(IntPtr)APPCOMMAND_VOLUME_MUTE);
}
private void btnDecVol_Click(object sender, EventArgs e)
{
SendMessageW(this.Handle, WM_APPCOMMAND, this.Handle,(IntPtr)APPCOMMAND_VOLUME_DOWN);
}
private void btnIncVol_Click(object sender, EventArgs e)
{
SendMessageW(this.Handle, WM_APPCOMMAND,this.Handle,(IntPtr)APPCOMMAND_VOLUME_UP);
}
}
}
But I got an error at the highlighted places...as shown below...i got this code from some internet sources

Vulpes · Answer

It looks like all the code you have in your VolumeChange class is designed to be placed directly within a windows form not just an ordinary class. You can tell that from the presence of the 3 button Click handlers for muting decreasing or increasing the volume. 'this.Handle' will then work because all forms have a Handle property. So I'd move all the code inside a form and add the 'skeleton' Click handlers for the 3 buttons by double clicking on them within the VS designer rather than manually.

Naredla Nithesh · Answer

Go and see this link http://msdn.microsoft.com/en-us/library/aa719104.aspx

Dipankar Biswas · Answer

use C# using System; using System.Windows.Forms; using System.Runtime.InteropServices; namespace WindowsFormsApplication1 { 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 btnMute_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); } } }

Dipankar Biswas · Answer

Imports System Imports System.Windows.Forms Imports System.Runtime.InteropServices Partial Public Class Form2 Inherits Form Private Const APPCOMMAND_VOLUME_MUTE As Integer = &H80000 Private Const APPCOMMAND_VOLUME_UP As Integer = &HA0000 Private Const APPCOMMAND_VOLUME_DOWN As Integer = &H90000 Private Const WM_APPCOMMAND As Integer = &H319 _ Public Shared Function SendMessageW(ByVal hWnd As IntPtr _ ByVal Msg As Integer ByVal wParam As IntPtr _ ByVal lParam As IntPtr) As IntPtr End Function Private Sub Button1_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button1.Click SendMessageW(Me.Handle WM_APPCOMMAND _ Me.Handle New IntPtr(APPCOMMAND_VOLUME_MUTE)) End Sub Private Sub Button2_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button2.Click SendMessageW(Me.Handle WM_APPCOMMAND _ Me.Handle New IntPtr(APPCOMMAND_VOLUME_DOWN)) End Sub Private Sub Button3_Click(ByVal sender As System.Object ByVal e As System.EventArgs) Handles Button3.Click SendMessageW(Me.Handle WM_APPCOMMAND _ Me.Handle New IntPtr(APPCOMMAND_VOLUME_UP)) End Sub End Class