Question

From a .net application I wish to capture all keyboard events, globally.

I set a callback using a win32-method SetWindowsHookEx(WH_KEYBOARD, HINSTANCE). (Using dllimport and some mashall-call.)

One the first key is pressed I get a nice response saying which key is pressed.
My callback-function calls CallNextHookEx as is should do.
But after the first event I get no more events.

Any-one has any idea of common causes for events to stop coming?

Answer 1

WH_KEYBOARD is not supported from a managed wrapper, it needs to inject itself into the process.

You can use WH_KEYBOARD_LL which will be called in the declaring thread.

see: http://support.microsoft.com/kb/318804

Global hooks are not supported in the
.NET Framework Except for the
WH_KEYBOARD_LL low-level hook and the
WH_MOUSE_LL low-level hook, you cannot
implement global hooks in the
Microsoft .NET Framework. To install a
global hook, a hook must have a native
DLL export to inject itself in another
process that requires a valid,
consistent function to call into. This
behavior requires a DLL export. The
.NET Framework does not support DLL
exports. Managed code has no concept
of a consistent value for a function
pointer because these function
pointers are proxies that are built
dynamically.

Low-level hook procedures are called
on the thread that installed the hook.
Low-level hooks do not require that
the hook procedure be implemented in a
DLL.