Windows User Action Hook (EventHook)

Code Quality

A .NET library to subscribe to Windows global user actions: keyboard, mouse, clipboard, application windows, print jobs, and hotkeys.

Requires: .NET 10 on Windows (net10.0-windows). AnyCPU — works on x86, x64, and ARM64 Windows when P/Invoke pointer sizes are correct (v2 fixes these).

• API Documentation (generated DocFX site on develop)

Install

dotnet add package EventHook

Sample

using System;
using System.Windows.Forms;

using (var eventHookFactory = new EventHookFactory())
{
    var keyboardWatcher = eventHookFactory.GetKeyboardWatcher();
    keyboardWatcher.Start();
    keyboardWatcher.OnKeyInput += (s, e) =>
        Console.WriteLine($"Key {e.KeyData.EventType} of {e.KeyData.Keyname}");

    var mouseWatcher = eventHookFactory.GetMouseWatcher();
    mouseWatcher.IncludeMouseMove = false; // #28
    mouseWatcher.Start();
    mouseWatcher.OnMouseInput += (s, e) =>
        Console.WriteLine($"Mouse {e.Message} at {e.Point.x},{e.Point.y}");

    var clipboardWatcher = eventHookFactory.GetClipboardWatcher();
    clipboardWatcher.Start();
    clipboardWatcher.OnClipboardModified += (s, e) =>
        Console.WriteLine($"Clipboard {e.DataFormat}: {e.Data}");

    var applicationWatcher = eventHookFactory.GetApplicationWatcher();
    applicationWatcher.Start();
    applicationWatcher.OnApplicationWindowChange += (s, e) =>
        Console.WriteLine($"{e.ApplicationData.AppName} was {e.Event}");

    var printWatcher = eventHookFactory.GetPrintWatcher();
    printWatcher.Start();
    printWatcher.OnPrintEvent += (s, e) =>
        Console.WriteLine($"Printer {e.EventData.PrinterName} pages={e.EventData.Pages}");

    var hotkeyWatcher = eventHookFactory.GetHotkeyWatcher();
    hotkeyWatcher.Start();
    hotkeyWatcher.Register("demo", Keys.Control | Keys.Alt | Keys.H);
    hotkeyWatcher.OnHotkeyPressed += (s, e) =>
        Console.WriteLine($"Hotkey {e.Id} ({e.Keys})");

    Console.ReadLine();
}

Application window filter

EventHook.Helpers.AppWindowFilter.IncludeWindowsWithoutSysMenu = true; // games without WS_SYSMENU
EventHook.Helpers.AppWindowFilter.IncludeDialogs = true;               // MessageBox / #32770
EventHook.Helpers.AppWindowFilter.CustomFilter = hwnd => true;         // optional

Hosted apps (COM / Office add-ins)

Prefer constructing the factory on an STA UI thread, or pass an existing message-pump HWND:

using var factory = new EventHookFactory(hostMainWindowHandle);

VB.NET

See examples/EventHook.VB.Example. Context-menu paste is observed via the clipboard watcher (global); WM_PASTE itself is application-local.

Print to PDF

PrintWatcher enumerates local and connected queues, including virtual printers such as Microsoft Print to PDF. Print a document to that queue to verify OnPrintEvent.

Development

• Visual Studio 2022 / .NET 10 SDK
• dotnet build src/EventHook.sln -c Release
• dotnet test tests/EventHook.Tests
• dotnet test tests/EventHook.IntegrationTests
• Docs: dotnet tool restore then docfx .github/docfx.json (writes API HTML under docs/, same as titanium-web-proxy)

Release branches

Branch	NuGet	Notes
develop	(no publish)	CI build + tests + DocFX
beta	{VersionPrefix}-beta from EventHook.csproj	Merge develop → beta to publish prerelease
stable / tag v*	{VersionPrefix} from csproj	Stable release + GitHub Pages docs

Publishing uses NuGet Trusted Publishing (NUGET_USER on the nuget-publish environment), same pattern as titanium-web-proxy.

Version 2.0 notes

Breaking: targets net10.0-windows only (no longer .NET Framework 4.5).

Highlights: HotkeyWatcher, mouse-move filter, clipboard images/files, dialog/MsgBox tracking, PDF/virtual printers, x64/ARM64 P/Invoke fixes, reliable Stop/Dispose, GitHub Actions CI + DocFX.