Open Source C# User Interface (UI) Software for Windows

.NET Multi-platform App UI (.NET MAUI) is a cross-platform framework for creating mobile and desktop apps with C# and XAML. Using .NET MAUI, you can develop apps that can run on Android, iOS, iPadOS, macOS, and Windows from a single shared codebase. .NET Multi-platform App UI (.NET MAUI) is the evolution of Xamarin.Forms that expands capabilities beyond mobile Android and iOS into desktop apps for Windows and macOS. With .NET MAUI, you can build apps that perform great for any device that runs Windows, macOS, Android, & iOS from a single codebase. Coupled with Visual Studio productivity tools and emulators, .NET and Visual Studio significantly speed up the development process for building apps that target the widest possible set of devices. Use a single development stack that supports the best of breed solutions for all modern workloads with a unified SDK, base class libraries, and toolchain.

Avalonia is a cross-platform UI framework for dotnet, providing a flexible styling system and supporting a wide range of Operating Systems such as Windows, Linux, macOS. Avalonia is mature and production-ready. We also have in beta release support for iOS, Android and in early stages support for browsers via WASM. Avalonia is open source, free to use, and always will be. Clone the source today to dig deeper. The free VS extension provides everything needed to start, including a XAML previewer. JetBrains deep understanding of Avalonia shines through with rich Rider and R# support. Deploy to the platforms you care about with ease. Leverage existing knowledge, code and packages to kickstart your project. Get the support your project needs with one of our commercial support agreements. Help you can count on. JetBrains delivers huge productivity gains for Avalonia developers.

An advanced, composable, functional reactive model-view-viewmodel framework for all .NET platforms! Describe what you want, not how to do it & rejoice in the increased readability of your code. Code is communication between people, that also happens to run on a computer. If you optimise for reading by humans, then over a long time your project will end up better. Create re-usable chunks of functionality that can be seamlessly integrated into your reactive pipelines. These chunks might be widely applicable, or specific to your application. Regardless, you have the power to write and test code once, and leverage it many times over. Any device, any platform. Share business logic between your mobile and desktop applications. ReactiveUI has first class support for Xamarin Forms, Xamarin.iOS, Xamarin.Android, Xamarin.Mac, Tizen, Windows Forms, Windows Presentation Foundation (WPF), & Universal Windows Platform (UWP).

FlaUI is a .NET library which helps with automated UI testing of Windows applications (Win32, WinForms, WPF, Store Apps,...). It is based on native UI Automation libraries from Microsoft and therefore kind of a wrapper around them. FlaUI wraps almost everything from the UI Automation libraries but also provides the native objects in case someone has a special need that is not covered (yet) by FlaUI. Some ideas are copied from the UIAComWrapper project or TestStack.White but rewritten from scratch to have a clean codebase. To use FlaUI, you need to reference the appropriate assemblies. So you should decide, if you want to use UIA2 or UIA3 and install the appropriate library from NuGet. You can of course always download the source and compile it yourself. The entry point is usually an application or the desktop so you get an automation element (like a the main window of the application). On this, you can then search sub-elements and interact with them.

Windows Presentation Foundation (WPF) is a UI framework for building Windows desktop applications. WPF supports a broad set of application development features, including an application model, resources, controls, graphics, layout, data binding and documents. WPF uses the Extensible Application Markup Language (XAML) to provide a declarative model for application programming. WPF applications are based on a vector graphics architecture. This enables applications to look great on high DPI monitors, as they can be infinitely scaled. WPF also includes a flexible hosting model, which makes it straightforward to host a video in a button, for example. The visual designer provided in Visual Studio makes it easy to build WPF application, with drag-in-drop and/or direct editing of XAML markup. WinForms is another UI framework for building Windows desktop applications that is supported on .NET (6.0.x/5.0.x/3.1.x). WPF and WinForms applications only run on Windows.

MahApps.Metro is a framework that allows developers to cobble together a Metro or Modern UI for their own WPF applications with minimal effort. MahApps.Metro overrides the default style of all common WPF controls and gives them a modern look. MahApps.Metro also includes some custom controls based on concepts from Windows Phone, Windows 8 and Window 10 (UWP) Apps. You can install MahApps.Metro via the NuGet UI or with the Package Manager Console. If you want to use a pre-release packages of MahApps.Metro, you need to enable Include Prerelease in the NuGet UI. All resources of MahApp.Metro are located within separate resource dictionaries. To adopt the MahApps.Metro theme, you will need to add the resource dictionaries to your App.xaml. To start with the full MahApps styling and full window support you need to change your normal Window to our MetroWindow.

Ooui (pronounced weee!) is a small cross-platform UI library for .NET that uses web technologies. It presents a classic object-oriented UI API that controls a dumb browser. With Ooui, you get the full power of your favorite .NET programming language plus the ability to interact with your app using any device. Make sure to add a reference to Ooui before you start running! With just code, a web server that serves the HTML and web socket logic necessary for an interactive button will start. Ooui has been broken up into several packages to increase the variety of ways that it can be used. When the user requests a page, the page will connect to the server using a web socket. This socket is used to keep the server's in-memory model of the UI (the one you work with as a programmer) in sync with the actual UI shown to the user in their browser. This is done using a simple messaging protocol with JSON packets.

With its familiar .Net visual drag n' drop, WYSIWYG designer and HTML5 rendering engine, Visual WebGui is the natural choice for core Visual Studio developers who want to create native quality, cross-platform enterprise level HTML5 apps in VB.NET or C#.

LITS is a game development engine, which offers basic implementations of the most needed interfaces: Graphic, Network, Sound and Input. All interfaces have several (parts plattform independent) wrappers which can be choosen as needed.

GUI Skinning System for Windows Forms .Net projects. This was a test for creating dynamic skins and has now been abandoned.

Framework for making Windows applications that are one .exe file in AutoHotKey_L,C++,C#, VB.NET,Java,Groovy,Common Lisp,Nemerle,Ruby,Python,PHP,Lua,Tcl,Perl,Jint,S#,WSH VBScript,HTML/JavaScript/CSS,COM, PowerShell without compiling . For .NET 4.

AODL,a C# .net library for creating / editing documents in the OpenDocument Format ( ODF ). Requires no knowledge about the ODF XML schema itself. AODC, an OpenDocument Converter & Embed OpenOffice as .net Control

Fireball FX is project that aim to create the best controls and libraries for developer, the project already contains some control, CodeEditorControl, Collections,Outlook Navigation bar and etc.. New Releases and source now at http://www.codeplex.com

A docking framework library for Gtk Sharp developments.

GLWidget is a cross-platform GTKSharp widget that supports OpenGL using the OpenTK library inside a GTK# application using C#.

Karna .NET is freeware C# library for fast developing widgets, docks, screenlets and other types of Internet Desktop Applications, that merges the best qualities and behaviors of the the web and desktop in both end-user experience and in development

Abzu provides everything from basic to advanced console features for any .net console project.

Very useful framework library, contains many frequent used code snippets, algorithms, data structures, WinForms & APS.NET controls for all-day work.

.Net C# command line parser that takes advantage of .Net features. Simple to use with command line switches for common data types. Automatically discovers switch data type by reflection on application properties. Less coding, standard parser.

.NET Assemblies that integrate and expands on various advanced solutions for DataBinding, Reflection, UI Wrapping and more. Fuel your .NET applications with RAD techniques and ready-to-use code that picks up where the .NET framework left off.

The aim of the project is to build up a set of components for enabling windows to dock into a designated form. Apart from this the main issue (and advantage) will be that every dockable window is handled like a common form in design-time. Language: C#

The Lighting Framework is a framework for rapidly designing, developing and deploying Windows Forms Smart Client applications using Microsoft’s .NET framework. The Framework frees the developer from the mundane task of creating the application shell.

OSGi.NET, a dynamic modularization framework, which is a .NET implementation tightly based on OSGi specifications from OSGi Alliance, is designed and developed by Xi’an UI Information Technology, Inc., in China, from 2008, it's totally free and can be redistributed with any production. This project is mainly focus on explaining how to develop OSGi.NET based application, and how to integrate with third part libraries to speed up our development.

THIS PROJECT IS DEAD. For the real appcelerator project, please visit http://www.appcelerator.com

XUP (Extensible User Interface Protocol) is a SOAP-based protocol for delivering events and incremental UI updates. This project builds a web application development framework on top of XUP, consisting of a client, a server toolkit, and a template viewer.