72 lines
1.5 KiB
C#
72 lines
1.5 KiB
C#
/*
|
|
* Copyright (c) 2022 ETH Zürich, Educational Development and Technology (LET)
|
|
*
|
|
* This Source Code Form is subject to the terms of the Mozilla Public
|
|
* License, v. 2.0. If a copy of the MPL was not distributed with this
|
|
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
|
|
*/
|
|
|
|
using System;
|
|
using System.Windows.Input;
|
|
using SafeExamBrowser.WindowsApi.Contracts;
|
|
using SafeExamBrowser.WindowsApi.Contracts.Events;
|
|
|
|
namespace SafeExamBrowser.UserInterface.Shared.Activators
|
|
{
|
|
public abstract class KeyboardActivator
|
|
{
|
|
private Guid? hookId;
|
|
private INativeMethods nativeMethods;
|
|
private bool paused;
|
|
|
|
protected KeyboardActivator(INativeMethods nativeMethods)
|
|
{
|
|
this.nativeMethods = nativeMethods;
|
|
}
|
|
|
|
protected abstract bool Process(Key key, KeyModifier modifier, KeyState state);
|
|
|
|
public void Pause()
|
|
{
|
|
OnBeforePause();
|
|
paused = true;
|
|
}
|
|
|
|
public void Resume()
|
|
{
|
|
OnBeforeResume();
|
|
paused = false;
|
|
}
|
|
|
|
public void Start()
|
|
{
|
|
hookId = nativeMethods.RegisterKeyboardHook(KeyboardHookCallback);
|
|
}
|
|
|
|
public void Stop()
|
|
{
|
|
if (hookId.HasValue)
|
|
{
|
|
nativeMethods.DeregisterKeyboardHook(hookId.Value);
|
|
}
|
|
}
|
|
|
|
protected virtual void OnBeforePause()
|
|
{
|
|
}
|
|
|
|
protected virtual void OnBeforeResume()
|
|
{
|
|
}
|
|
|
|
private bool KeyboardHookCallback(int keyCode, KeyModifier modifier, KeyState state)
|
|
{
|
|
if (!paused)
|
|
{
|
|
return Process(KeyInterop.KeyFromVirtualKey(keyCode), modifier, state);
|
|
}
|
|
|
|
return false;
|
|
}
|
|
}
|
|
}
|