Detecting music keys from keyboard in winform app

[Wheels012]

Good morning. I am trying to detect the music button events from the keyboard, but have been unsuccessful so far. I have the following code:

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

namespace KPlayer
{
public partial class Form1 : Form
{
WMPLib.WindowsMediaPlayer wmp = new WMPLib.WindowsMediaPlayer();
WMPLib.IWMPPlaylist pl;
//WMPLib.IWMPPlaylistArray plItems;
WMPLib.IWMPMedia media;

    // Required designer variable
    //private System.ComponentModel.Container components = null;

    ArrayList ar = new ArrayList();
    int intCount = 0;      
    List<int> numbers = new List<int>();
  
    float currentSize = 10;
    string currentFont = "DS-Digital";

    public Form1()
    {
        // Required for Windows Form Designer support
        InitializeComponent();
    }
   
    \[STAThread\]
    // Declare Windows API calls used to access Windows hooks
    \[DllImport("user32.dll")\]

    public static extern int SetWindowsHookEx(int hookType,
                                               HookProc callback,
                                               int instance,
                                               int threadID);
    \[DllImport("user32.dll")\]
    public static extern int CallNextHookEx(int hookHandle, int code,
                                            int wparam, int lparam);
    \[DllImport("user32.dll")\]
    public static extern bool UnhookWindowsHookEx(int hookHandle);
    \[DllImport("user32.dll")\]
    public static extern int GetKeyState(int vKey);

    // Fields, constants, and structures used by the keyboard hook.
    int hookHandle = 0;
    HookProc cb = null;

    public const int WH\_KEYBOARD = 2;

    public const int HC\_ACTION = 0;
    public const int HC\_NOREMOVE = 3;

    public const int VK\_CONTROL = 0x11;
    public const int VK\_LWIN = 0x5B;
    public const int VK\_RWIN = 0x5C;
    public const int VK\_APPS = 0x5D;
    public const int VK\_LSHIFT = 0xA0;
    public const int VK\_RSHIFT = 0xA1;
    public const int VK\_LCONTROL = 0xA2;
    public const int VK\_RCONTROL = 0xA3;

[Covean]

Can you please post your call to SetWindowsHookEx. What hook are you using WH_KEYBOARD or WH_KEYBOARD_LL? Because the function delegate called by the hook (Proc in your case) can be called from threads/processes beyond your scope, you should not do this: textBox1.Text += "Browser Back key caught" + Environment.NewLine; Use an invoke or for testing purposes just trace.

Greetings Covean

[Wheels012]

Hi Covean. That is all the "hook" code I have. I am not exactly clear what you are asking for. WHEELS

[Covean]

Ok so this will be the problem. ^^ Without calling SetWindowsHookEx how should the system know what you wanna hook? :-D Somewhere you should call (for example at form init): IntPtr hHook = SetWindowsHookEx(WH_KEYBOARD or WH_KEYBOARD_LL(for low-level hook), Proc (delegate to your hook proc), Process.GetCurrentProcess().Handle, 0); if(hHook == IntPtr.Zero) { // hook failed } At destruction time call UnhookWindowsHookEx(hHook);

Greetings Covean

[Wheels012]

Now I understand. I have the following:

    // Click event handlers for button1 and button2.
    private void button1\_Click(object sender, System.EventArgs e)
    {
        // Set the keyboard hook.
        if (hookHandle == 0)
        {
            cb = new HookProc(Proc);
            hookHandle = SetWindowsHookEx(WH\_KEYBOARD, cb, 0,
                                          appdomain.GetCurrentThreadId( ));
        }
        else
        {
            textBox1.Text += "Hook already set" + Environment.NewLine;
        }
        textBox1.Text += "Start: " + hookHandle + Environment.NewLine;
    }

    private void button2\_Click(object sender, System.EventArgs e)
    {
        // Unhook the keyboard hook.
        textBox1.Text += "End: " + UnhookWindowsHookEx(hookHandle) +
                         Environment.NewLine;
        hookHandle = 0;
    }

I am coming up with an error on this line: hookHandle = SetWindowsHookEx(WH_KEYBOARD, cb, 0, appdomain.GetCurrentThreadId( )); appdomain doesn't exist in the current context. WHEELS

[Covean]

If you want to hook more than the input to your application, you should set dwThreadId to 0 and just set the instance handle (3rd parameter) to Process.GetCurrentProcess().Handle. Btw: appdomain does not exists its called AppDomain.

Greetings Covean

[Wheels012]

Still get same error when I capitalize appDomain. WHEELS

[Saksida Bojan]

Wheels012 wrote:

Still get same error when I capitalize appDomain. WHEELS

Still wrong. There are 2 letters to capatilaze: "AppDomain"