c# - KeyEventArgs to Timer.Tick -

i try keyeventargs tick. if thinks why i'm using timer, needs detect keypress outside of window too.

i don't have "error" in code, when run program comes:

exception unhandled. system.nullreferenceexpetion: (i try translate) 'your object referral can't define object occurrence'

now thing i'm using is

private void form1_load(object sender, eventargs e)          {              a.start();              a.interval = 1;          }    private void a_tick(object sender, eventargs e)          {              keyeventargs ke = e keyeventargs;              if (ke.keycode == keys.r)               {              test = true;                   }                 }              

i need help, because error has been long time. thanks

from looking @ way put question me seems you're trying detect key press using timer. instead can use form's keypress event.

use:

private void form1_keypress(object sender, keypresseventargs e) {     if (e.keycode == keys.something)     {         //do     } } 

don't forget set keypreview = true; form.

edit: if need detect keypresses without focus(outside of form), need global hotkey hooking. need following:

first include this:

using system.runtime.interopservices; 

you need @ top of class:

[dllimport("user32.dll")]  public static extern bool registerhotkey(intptr hwnd, int id, int fsmodifiers, int vlc); [dllimport("user32.dll")] public static extern bool unregisterhotkey(intptr hwnd, int id); const int hotkey = 1; 

and need call inside form's load:

registerhotkey(this.handle, hotkey, (uint)modifierkeys.something, (uint) keys.something); 

then need handle press:

protected override void wndproc(ref message m)  {     if (m.msg == 0x0312 && m.wparam.toint32() == hotkey)      {         //do when pressed     }     base.wndproc(ref m); } 

wiki