SharpHook

SharpHook provides a cross-platform global keyboard and mouse hook, event simulation, and text entry simulation for .NET. It is a wrapper of libuiohook and provides direct access to its features as well as higher-level types to work with it.

Installation

dotnet add package SharpHook
dotnet add package SharpHook.Reactive

Upgrading

A migration guide is available for upgrading between major versions.

Docs

You can find more information (including the API reference) in the docs at https://sharphook.tolik.io. Or if you need a specific version:

• v5.3.2 | v5.3.1 | v5.3.0
• v5.2.3 | v5.2.2 | v5.2.1 | v5.2.0
• v5.1.2 | v5.1.1 | v5.1.0
• v5.0.0
• v4.2.1 | v4.2.0
• v4.1.0
• v4.0.1 | v4.0.0
• v3.1.3 | v3.1.2 | v3.1.1 | v3.1.0
• v3.0.2 | v3.0.1 | v3.0.0
• v2.0.0
• v1.1.0
• v1.0.1 | v1.0.0

Supported Platforms

SharpHook targets .NET 6+, .NET Framework 4.6.2+, and .NET Standard 2.0. The following table describes the availability of SharpHook on various platforms:

	Windows	macOS	Linux
x86	Yes	N/A	No
x64	Yes	Yes	Yes
Arm32	No	N/A	Yes
Arm64	Yes	Yes	Yes

Platform support notes:

• Windows 10/11 is supported. Arm32 is not supported since its support was removed in .NET 5.

• macOS 10.15+ is supported. Mac Catalyst is also supported (13.1+). macOS requires that the accessibility API be enabled for the application if it wants to create a global hook.

• Linux distributions supported by .NET are supported by SharpHook. Linux on x86 is not supported by .NET itself. Only X11 is supported - Wayland support may be coming, but it's not yet here.

More info on OS support can be found in an article on OS-specific constraints.

Usage

Native Functions of libuiohook

SharpHook exposes the functions of libuiohook in the SharpHook.Native.UioHook class. The SharpHook.Native namespace also contains types which represent the data used by libuiohook.

In general, you don't need to use the native methods directly. Instead, use the higher-level interfaces and classes provided by SharpHook. However, you should still read this section to know how the high-level features work under the hood.

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 keyboard and mouse global hook and runs it on the current thread, blocking it until Stop is called.
• RunKeyboard - creates a keyboard-only global hook and runs it on the current thread, blocking it until Stop is called.
• RunMouse - creates a mouse-only global hook and runs it on the current thread, blocking it until Stop is called.
• Stop - destroys the global hook.

You have to remember that only one global hook can exist at a time since calling SetDispatchProc will override the previously set one.

Additionally, UioHook contains the PostEvent method for simulating input events, and the SetLoggerProc method for setting the log callback.

SharpHook also provides text entry simulation and UioHook contains the PostText method. The text to simulate doesn't depend on the current keyboard layout. The full range of UTF-16 (including surrogate pairs, e.g. emojis) is supported.

libuiohook also provides functions to get various system properties. The corresponding methods are also present in UioHook.

If you want to use the low-level functionality, you don't need to use the UioHook class directly. Instead you can use interfaces in the SharpHook.Providers namespace. The methods in those interfaces are the same as in the UioHook class. SharpHook.Providers.UioHookProvider implements all of these interfaces and simply calls the corresponding methods in UioHook. This should be done to decouple your code from UioHook and make testing easier.

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:

using SharpHook;

// ...

var hook = new TaskPoolGlobalHook();

hook.HookEnabled += OnHookEnabled;     // EventHandler<HookEventArgs>
hook.HookDisabled += OnHookDisabled;   // EventHandler<HookEventArgs>

hook.KeyTyped += OnKeyTyped;           // EventHandler<KeyboardHookEventArgs>
hook.KeyPressed += OnKeyPressed;       // EventHandler<KeyboardHookEventArgs>
hook.KeyReleased += OnKeyReleased;     // EventHandler<KeyboardHookEventArgs>

hook.MouseClicked += OnMouseClicked;   // EventHandler<MouseHookEventArgs>
hook.MousePressed += OnMousePressed;   // EventHandler<MouseHookEventArgs>
hook.MouseReleased += OnMouseReleased; // EventHandler<MouseHookEventArgs>
hook.MouseMoved += OnMouseMoved;       // EventHandler<MouseHookEventArgs>
hook.MouseDragged += OnMouseDragged;   // EventHandler<MouseHookEventArgs>

hook.MouseWheel += OnMouseWheel;       // EventHandler<MouseWheelHookEventArgs>

hook.Run();
// or
await hook.RunAsync();

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).

Hook events are of type HookEventArgs or a derived type which contains more info. It's possible to suppress event propagation by setting the SuppressEvent property to true inside the event handler. This must be done synchronously and is only supported on Windows and macOS. You can check the event time and whether the event is real or simulated with the EventTime and IsEventSimulated properties respectively.

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. Running a global hook when another global hook is already running will corrupt the internal global state of libuiohook.

You can create a keyboard-only or a mouse-only hook by passing a GlobalHookType to the hook's constructor. This makes a difference only on Windows where there are two different global hooks - a keyboard hook and a mouse hook. On macOS and Linux there is one hook for all events, and this simply enables filtering keyboard or mouse events out on these OSes.

SharpHook provides two implementations of IGlobalHook:

• SharpHook.SimpleGlobalHook runs all of its event handlers on the same thread on which 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.

• SharpHook.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 SharpHook.GlobalHookBase class which you can extend to create your own implementation of the global hook. It calls the appropriate event handlers, and you only need to implement a strategy for dispatching the events. It also contains a finalizer which will stop the global hook if this object is not reachable anymore.

Reactive Global Hooks

If you're using Rx.NET, you can use the SharpHook.Reactive package to integrate SharpHook with Rx.NET.

SharpHook.Reactive provides the SharpHook.Reactive.IReactiveGlobalHook interface along with a default implementation which you can use to use to control the hook and subscribe to its observables. Here's a basic example:

using SharpHook.Reactive;

// ...

var hook = new SimpleReactiveGlobalHook();

hook.HookEnabled.Subscribe(OnHookEnabled);
hook.HookDisabled.Subscribe(OnHookDisabled);

hook.KeyTyped.Subscribe(OnKeyTyped);
hook.KeyPressed.Subscribe(OnKeyPressed);
hook.KeyReleased.Subscribe(OnKeyReleased);

hook.MouseClicked.Subscribe(OnMouseClicked);
hook.MousePressed.Subscribe(OnMousePressed);
hook.MouseReleased.Subscribe(OnMouseReleased);

hook.MouseMoved
    .Throttle(TimeSpan.FromSeconds(0.5))
    .Subscribe(OnMouseMoved);

hook.MouseDragged
    .Throttle(TimeSpan.FromSeconds(0.5))
    .Subscribe(OnMouseDragged);

hook.MouseWheel.Subscribe(OnMouseWheel);

hook.Run();
// or
hook.RunAsync().Subscribe();

Reactive global hooks are basically the same as the default global hooks and the same rules apply to them.

SharpHook.Reactive provides two implementations of IReactiveGlobalHook:

• SharpHook.Reactive.SimpleReactiveGlobalHook. Since we're dealing with observables, it's up to you to decide when and where to handle the events through schedulers. A default scheduler can be specified for all observables.

• SharpHook.Reactive.ReactiveGlobalHookAdapter adapts an IGlobalHook to IReactiveGlobalHook. All subscriptions and changes are propagated to the adapted hook. There is no default adapter from IReactiveGlobalHook to IGlobalHook. A default scheduler can be specified for all observables.

Event Simulation

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);

// Press the left mouse button at (0, 0)
simulator.SimulateMousePress(0, 0, MouseButton.Button1);

// Release the left mouse button at (0, 0)
simulator.SimulateMouseRelease(0, 0, 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(
    rotation: -120,
    direction: MouseWheelScrollDirection.Vertical, // Vertical by default
    type: MouseWheelScrollType.UnitScroll); // UnitScroll by default

SharpHook provides the IEventSimulator interface, and the default implementation, EventSimulator, which calls UioHook.PostEvent to simulate the events.

Text Entry Simulation

SharpHook also provides text entry simulation. IEventSimulator contains the SimulateTextEntry method which accepts a string. The text to simulate doesn't depend on the current keyboard layout. The full range of UTF-16 (including surrogate pairs, e.g. emojis) is supported.

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.RegisterOrGet(minLevel: LogLevel.Info);
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.

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.

SharpHook.Reactive contains the IReactiveLogSource and ReactiveLogSourceAdapter so you can use them in a more reactive way:

using SharpHook.Logging;
using SharpHook.Reactive.Logging;

// ...

var logSource = LogSource.RegisterOrGet(minLevel: LogLevel.Info);
var reactiveLogSource = new ReactiveLogSourceAdapter(logSource);
reactiveLogSource.MessageLogged.Subscribe(this.OnMessageLogged);

Testing

SharpHook provides two classes which make testing easier. They aren't required since mocks can be used instead, but unlike mocks, no setup is required to use these classes.

SharpHook.Testing.TestGlobalHook provides an implementation of IGlobalHook and IEventSimulator which can be used for testing. When the Run or RunAsync method is called, it will dispatch events using the various Simulate methods from IEventSimulator.

If this class is used as an IEventSimulator in the tested code, then the SimulatedEvents property can be checked to see which events were simulated using the test instance.

If an IReactiveGlobalHook is needed for testing, then ReactiveGlobalHookAdapter can be used to adapt an instance of TestGlobalHook.

If the low-level functionality of SharpHook should be mocked, or mocking should be pushed as far away as possible, then SharpHook.Testing.TestProvider can be used. It implements every interface in the SharpHook.Providers namespace and as such it can be used instead of a normal low-level functionality provider.

Like TestGlobalHook, this class can post events using the PostEvent method and dispatch them if Run was called. It also contains the PostedEvents property.

Building from Source

In order to build this library, you'll first need to get libuiohook binaries. You you can get a nightly build from this repository, or you can build them yourself as instructed in the libuiohook fork that SharpHook uses (not recommended as it's non-trivial, and you should most probably use the same options that the build in this repository uses anyway).

Place the binaries into the appropriate directories in the SharpHook project, as described in the following table:

OS	File	Source directory	Target directory
Windows	uiohook.dll	windows/<platform>/bin	lib/win-<platform>
macOS	libuiohook.dylib	darwin/<platform>/lib	lib/osx-<platform>
Mac Catalyst	libuiohook.dylib	catalyst/<platform>/lib	lib/maccatalyst-<platform>
Linux	libuiohook.so	linux/<platform>/lib	lib/linux-<platform>

With libuiohook in place you can build SharpHook using your usual methods, e.g. with Visual Studio or the dotnet CLI. You need .NET 8 to build SharpHook.

Library Status

I will maintain the library to keep up with the releases of libuiohook which uses a rolling release model - every commit to its 1.3 branch is considered stable. If you've noticed that this library hasn't gotten new commits in some time, rest assured that it's not abandoned! I'm not giving up on this library any time soon.

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