SharpHook provides a cross-platform global keyboard and mouse hook for .NET, and the ability to simulate input events.
It is a thin wrapper of libuiohook and provides direct access to its features as
well as higher-level types to work with it.
Usage
Native Functions of libuiohook
SharpHook exposes the functions of libuiohook in the SharpHook.Native.UioHook class. The SharpHook.Native
namespace also contains structs and enums which represent the data returned by libuiohook.
Note: In general, you don't need to use the native methods directly. Instead, use the higher-level types provided by
SharpHook.
UioHook contains the following methods for working with the global hook:
SetDispatchProc - sets the function which will be called when an event is raised by libuiohook.
Run - creates a global hook and runs it on the current thread, blocking it until Stop is called.
Stop - destroys the global hook.
Additionally, UioHook contains the PostEvent method for simulating input events, and the SetLoggerProc method for
setting the log callback.
libuiohook also provides functions to get various system properties. The corresponding methods are also present in
UioHook.
Important: An application manifest is required on Windows to enable DPI awareness for your app. If it's not enabled
then mouse coordinates will be wrong on high-DPI screens. You can look at the sample app in this repository to see the
manifest example.
Default Global Hooks
SharpHook provides the IGlobalHook interface along with two default implementations which you can use to control the
hook and subscribe to its events. Here's a basic usage example:
First, you create the hook, then subscribe to its events, and then run it. The Run method runs the hook on the current
thread, blocking it. The RunAsync() method runs the hook on a separate thread and returns a Task which is finished
when the hook is destroyed. You can subscribe to events after the hook is started.
IGlobalHook extends IDisposable. When you call the Dispose method on a hook, it's destroyed. The contract of
the interface is that once a hook has been destroyed, it cannot be started again - you'll have to create a new instance.
Calling Dispose when the hook is not running is safe - it just won't do anything (other than marking the instance as
disposed).
Important: Always use one instance of IGlobalHook at a time in the entire application since they all must use
the same static method to set the hook callback for libuiohook, so there may only be one callback at a time.
SharpHook provides two implementations of IGlobalHook:
SimpleGlobalHook runs all of its event handlers on the same thread where the hook itself runs. This means that the
handlers should generally be fast since they will block the hook from handling the events that follow if they run for
too long.
TaskPoolGlobalHook runs all of its event handlers on other threads inside the default thread pool for tasks. The
parallelism level of the handlers can be configured. On backpressure it will queue the remaining handlers. This means
that the hook will be able to process all events. This implementation should be preferred to SimpleGlobalHook except
for very simple use-cases. But it has a downside - suppressing event propagation will be ignored since event handlers
are run on other threads.
The library also provides the GlobalHookBase class which you can extend to create your own implementation of the
global hook. It calls appropriate event handlers, and you only need to implement a strategy for dispatching the events.
SharpHook provides the ability to simulate keyboard and mouse events in a cross-platform way as well. Here's a quick
example:
using SharpHook;
using SharpHook.Native;
// ...
var simulator = new EventSimulator();
// Press Ctrl+C
simulator.SimulateKeyPress(KeyCode.VcLeftControl);
simulator.SimulateKeyPress(KeyCode.VcC);
// Release Ctrl+C
simulator.SimulateKeyRelease(KeyCode.VcC);
simulator.SimulateKeyRelease(KeyCode.VcLeftControl);
// Press the left mouse button
simulator.SimulateMousePress(MouseButton.Button1);
// Release the left mouse button
simulator.SimulateMouseRelease(MouseButton.Button1);
// Move the mouse pointer to (0, 0)
simulator.SimulateMouseMovement(0, 0);
// Move the mouse pointer 50 pixels to the right and 100 pixels down
simulator.SimulateMouseMovementRelative(50, 100);
// Scroll the mouse wheel
simulator.SimulateMouseWheel(2, -120);
SharpHook provides the IEventSimulator interface, and the default implementation, EventSimulator, which calls
UioHook.PostEvent to simulate the events.
Logging
libuiohook can log messages throughout its execution. By default the messages are not logged anywhere, but you can get
these logs by using the ILogSource interface and its default implementation, LogSource:
using SharpHook.Logging;
// ...
var logSource = LogSource.Register();
logSource.MessageLogged += this.OnMessageLogged;
private void OnMessageLogged(object? sender, LogEventArgs e) =>
this.logger.Log(this.AdaptLogLevel(e.LogEntry.Level), e.LogEntry.FullText);
As with global hooks, you should use only one LogSource object at a time. ILogSource extends IDisposable - you
can dispose of a log source to stop receiving libuiohook messages. You should keep a reference to an instance of
LogSource when you use it since it will stop receiving messages when garbage collector deletes it, to avoid memory
leaks.
An EmptyLogSource class is also available - this class doesn't listen to the libuiohook logs and can be used instead
of LogSource in release builds.