/// <summary>
/// A callback function which will be called every Time a keyboard activity detected.
/// </summary>
/// <param name="nCode">
/// [in] Specifies whether the hook procedure must process the message.
/// If nCode is HC_ACTION, the hook procedure must process the message.
/// If nCode is less than zero, the hook procedure must pass the message to the
/// CallNextHookEx function without further processing and must return the
/// value returned by CallNextHookEx.
/// </param>
/// <param name="wParam">
/// [in] Specifies whether the message was sent by the current thread.
/// If the message was sent by the current thread, it is nonzero; otherwise, it is zero.
/// </param>
/// <param name="lParam">
/// [in] Pointer to a CWPSTRUCT structure that contains details about the message.
/// </param>
/// <returns>
/// If nCode is less than zero, the hook procedure must return the value returned by CallNextHookEx.
/// If nCode is greater than or equal to zero, it is highly recommended that you call CallNextHookEx
/// and return the value it returns; otherwise, other applications that have installed WH_CALLWNDPROC
/// hooks will not receive hook notifications and may behave incorrectly as a result. If the hook
/// procedure does not call CallNextHookEx, the return value should be zero.
/// </returns>
private static int KeyboardHookProc(int nCode, int wParam, IntPtr lParam)
{
if (nCode < 0)
{
return(CallNextHookEx(keyboardHookHandle, nCode, wParam, lParam));
}
//Marshall the data from callback.
var info = (KeyboardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyboardHookStruct));
var extended = (info.Flags & LLKHF_EXTENDED) != 0;
var code = extended && info.VirtualKeyCode == VK_RETURN ? 1025 : info.VirtualKeyCode;
switch (wParam)
{
case WM_KEYDOWN:
case WM_SYSKEYDOWN:
KeyboardState.AddPressedElement(code, PressHold);
break;
case WM_KEYUP:
case WM_SYSKEYUP:
KeyboardState.RemovePressedElement(code, PressHold);
// Toggle the mouse trap.
if (code == TrapToggleKeyCode)
{
trapEnabled = !trapEnabled;
}
break;
}
if (KeyboardInsert?.Invoke(code) ?? false || (trapEnabled && TrapKeyboard))
{
return(1);
}
return(CallNextHookEx(keyboardHookHandle, nCode, wParam, lParam));
}