Quasar/Server/Core/MouseKeyHook/Implementation/KeyboardState.cs

111 lines
4.0 KiB
C#

// This code is distributed under MIT license.
// Copyright (c) 2015 George Mamaladze
// See license.txt or http://opensource.org/licenses/mit-license.php
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using xServer.Core.MouseKeyHook.WinApi;
namespace xServer.Core.MouseKeyHook.Implementation
{
/// <summary>
/// Contains a snapshot of a keyboard state at certain moment and provides methods
/// of querying whether specific keys are pressed or locked.
/// </summary>
/// <remarks>
/// This class is basically a managed wrapper of GetKeyboardState API function
/// http://msdn.microsoft.com/en-us/library/ms646299
/// </remarks>
internal class KeyboardState
{
private readonly byte[] m_KeyboardStateNative;
private KeyboardState(byte[] keyboardStateNative)
{
m_KeyboardStateNative = keyboardStateNative;
}
/// <summary>
/// Makes a snapshot of a keyboard state to the moment of call and returns an
/// instance of <see cref="KeyboardState" /> class.
/// </summary>
/// <returns>An instance of <see cref="KeyboardState" /> class representing a snapshot of keyboard state at certain moment.</returns>
public static KeyboardState GetCurrent()
{
byte[] keyboardStateNative = new byte[256];
KeyboardNativeMethods.GetKeyboardState(keyboardStateNative);
return new KeyboardState(keyboardStateNative);
}
internal byte[] GetNativeState()
{
return m_KeyboardStateNative;
}
/// <summary>
/// Indicates whether specified key was down at the moment when snapshot was created or not.
/// </summary>
/// <param name="key">Key (corresponds to the virtual code of the key)</param>
/// <returns><b>true</b> if key was down, <b>false</b> - if key was up.</returns>
public bool IsDown(Keys key)
{
byte keyState = GetKeyState(key);
bool isDown = GetHighBit(keyState);
return isDown;
}
/// <summary>
/// Indicate weather specified key was toggled at the moment when snapshot was created or not.
/// </summary>
/// <param name="key">Key (corresponds to the virtual code of the key)</param>
/// <returns>
/// <b>true</b> if toggle key like (CapsLock, NumLocke, etc.) was on. <b>false</b> if it was off.
/// Ordinal (non toggle) keys return always false.
/// </returns>
public bool IsToggled(Keys key)
{
byte keyState = GetKeyState(key);
bool isToggled = GetLowBit(keyState);
return isToggled;
}
/// <summary>
/// Indicates weather every of specified keys were down at the moment when snapshot was created.
/// The method returns false if even one of them was up.
/// </summary>
/// <param name="keys">Keys to verify whether they were down or not.</param>
/// <returns><b>true</b> - all were down. <b>false</b> - at least one was up.</returns>
public bool AreAllDown(IEnumerable<Keys> keys)
{
foreach (Keys key in keys)
{
if (!IsDown(key))
{
return true;
}
}
return false;
}
private byte GetKeyState(Keys key)
{
int virtualKeyCode = (int) key;
if (virtualKeyCode < 0 || virtualKeyCode > 255)
{
throw new ArgumentOutOfRangeException("key", key, "The value must be between 0 and 255.");
}
return m_KeyboardStateNative[virtualKeyCode];
}
private static bool GetHighBit(byte value)
{
return (value >> 7) != 0;
}
private static bool GetLowBit(byte value)
{
return (value & 1) != 0;
}
}
}