CsWebUi.Native 2.5.0-beta.4.2

<p align="center"> <img src="assets/cswebui-logo.svg" width="520" alt="CsWebUi"> </p>

CsWebUi

Modern .NET 10 bindings for WebUI: use an installed browser or supported WebView as a lightweight cross-platform desktop UI.

CsWebUi.Native is a direct, unsafe C ABI layer for WebUI 2.5.0-beta.4. CsWebUi adds deterministic window ownership, UTF-8 conversion, error handling, raw-data helpers, and safe synchronous or ValueTask-based callbacks.

This project follows WebUI's 2.5 beta ABI and is itself released as a prerelease package.

Use it

dotnet add package CsWebUi --prerelease

using CsWebUi;

using var window = new WebUiWindow();

window.Bind("multiply", static e =>
    WebUiResult.FromInt64(e.GetInt64() * e.GetInt64(1)));

window.BindAsync("greet", static (e, cancellationToken) =>
{
    cancellationToken.ThrowIfCancellationRequested();
    return ValueTask.FromResult<WebUiResult>($"Hello, {e.GetString()}!");
});

window.Show("""
    <!doctype html>
    <script src="webui.js"></script>
    <button onclick="multiply(6, 7).then(alert)">Multiply</button>
    <button onclick="greet('WebUI').then(alert)">Greet</button>
    """);

WebUiApplication.Wait();

WebUiWindow.Dispose() destroys the native window and safely defers final destruction until active managed callbacks finish. Async bindings automatically opt WebUI into its asynchronous-response mode; return a WebUiResult to resolve the JavaScript promise.

Packages

Release packages bundle the standard, non-TLS WebUI shared library for win-x64, linux-x64, linux-arm64, osx-x64, and osx-arm64. The raw TLS API remains available when an application supplies a secure custom WebUI build.

The bundled Windows shared library statically links the MSVC runtime, matching the official WebUI Windows distribution and avoiding a separate Visual C++ Redistributable prerequisite.

For a custom or locally built native library, configure it before the first WebUI call:

CsWebUi.Native.WebUiNativeLibrary.SetLibraryPath("/path/to/libwebui-2.so");

Alternatively set CSWEBUI_NATIVE_LIBRARY to a library file or its containing directory.

NixOS development

The flake pins both Nixpkgs and the upstream WebUI source revision. It builds webui-2, exposes it through CSWEBUI_NATIVE_LIBRARY, and includes .NET 10, CMake, Chromium, Xvfb, and Linux WebView dependencies.

nix develop
dotnet test
dotnet run --project samples/CsWebUi.BasicSample

Useful flake outputs:

nix build .#webui-native
nix flake check

Samples

• CsWebUi.BasicSample is the smallest possible callback example.
• CsWebUi.HighLevelSample is a complete local web application showcasing the safe window, event, async callback, binary-message, and JavaScript APIs.

Design notes

• The raw package uses explicit Cdecl LibraryImport declarations, nuint for size_t, one-byte C booleans, and unmanaged function pointers.
• Both packages are trimming- and NativeAOT-oriented. The high-level callback dispatcher has no reflection-based registration.
• The high-level API parses JavaScript numeric arguments and serializes double results with the invariant culture, avoiding process-locale differences in WebUI's raw float helpers.
• Empty high-level callback results complete correctly when async bindings are present; WebUI's direct empty-string helper otherwise leaves that response pending.
• Strings passed to WebUI reject embedded null characters instead of silently truncating at the native C-string boundary.
• WebUI owns pointers returned from event accessors and other borrowed APIs. The safe WebUiEvent wrapper invalidates access after the callback completes.
• Browser mode needs an installed browser. Embedded WebView mode has platform dependencies, including the WebView2 runtime/loader on Windows and GTK/WebKit on Linux.

License

CsWebUi is MIT licensed. WebUI is also MIT licensed; its attribution is retained in NOTICE.