Browse free open source C# Frameworks and projects below. Use the toggles on the left to filter open source C# Frameworks by OS, license, language, programming language, and project status.

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  • 1
    Windows Presentation Foundation (WPF)

    Windows Presentation Foundation (WPF)

    Framework for building Windows desktop applications

    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.
    Downloads: 7 This Week
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  • 2
    ASP.NET API Versioning

    ASP.NET API Versioning

    Libraries which add service API versioning to ASP.NET Web API

    ASP.NET API versioning gives you a powerful, but easy-to-use method for adding API versioning semantics to your new and existing REST services built with ASP.NET. The API versioning extensions define simple metadata attributes and conventions that you use to describe which API versions are implemented by your services. You don't need to learn any new routing concepts or change the way you implement your services in ASP.NET today. The default API versioning configuration is compliant with the versioning semantics outlined by the Microsoft REST Guidelines. There are also a number of customization and extension points available to support transitioning services that may not have supported API versioning in the past or supported API versioning with semantics that are different from the Microsoft REST versioning guidelines.
    Downloads: 6 This Week
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  • 3
    Pokemon Unity

    Pokemon Unity

    A framework to build Pokémon RPG games

    A framework to build Pokémon RPG games. I use IIcolour Spectrum's original Pokemon Unity as a base with Herbertmilhomme's framework. So far, this project use wrapper ( Legacy <=> Framework ), and in the future, I want to remove the wrapper. This project is playable, but it has some issues and some features are disabled. Use Unity Hub or Editor to import this project's folder (/Pokemon Unity). Build and run the project. There are also demos for Windows, Linux, and Mac zipped in Releases!
    Downloads: 6 This Week
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  • 4

    Okapi Framework (Old .NET version)

    See http://okapi.opentag.com/ for LATES VERSION of the Okapi Framework

    THIS VERSION ON SOURCEFORGE IS NO LONGER SUPPORTED and works only on Windows. The Okapi Framework is a set of components and tools for localization and translation tasks. THE NEWEST JAVA-BASED VERSION OF OKAPI IS AVAILABLE AT: http://okapi.opentag.com/ The new version runs on Windows, Mac, Linux, etc.
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    Downloads: 44 This Week
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    NHibernate
    .NET port of the excellent Java Hibernate which provides Object/Relational mapping to persist objects in a relational database.
    Downloads: 24 This Week
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  • 6
    Akavache

    Akavache

    An asynchronous, persistent key-value store

    An asynchronous, persistent key-value store created for writing desktop and mobile applications, based on SQLite3. Akavache is great for both storing important data as well as cached local data that expires. Downloading and storing remote data from the internet while still keeping the UI responsive is a task that nearly every modern application needs to do. However, many applications that don't take the consideration of caching into the design from the start often end up with inconsistent, duplicated code for caching different types of objects. Akavache is a library that makes common app patterns easy, and unifies caching of different object types (i.e. HTTP responses vs. JSON objects vs. images). It's built on a core key-value byte array store (conceptually similar to a Dictionary<string, byte[]>), and on top of that store, extensions are added to support Arbitrary objects via JSON.NET.
    Downloads: 5 This Week
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  • 7
    Entity Framework 6

    Entity Framework 6

    This is the codebase for Entity Framework 6

    Entity Framework 6 (EF6) is a proven object-relational (O/RM) mapper for .NET with many years of feature development and stabilization. Like O/RM, EF6 reduces the impedance mismatch between the relational and object-oriented worlds, allowing developers to write applications that interact with data stored in relational databases with strongly typed .NET objects that represent the domain of the database. application, and eliminate the need for much of the data access "mechanical" code that you would normally write. Mapping POCO entity classes that do not depend on any EF type. Models can be generated from existing databases and then manually edited, or they can be created from scratch and then used to generate new databases. Integration with .NET Framework application models, including ASP.NET, and through data binding, with WPF and WinForms. Database connectivity based on ADO.NET and various providers available to connect to SQL Server, Oracle, MySQL, SQLite, PostgreSQL, DB2, etc.
    Downloads: 5 This Week
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  • 8
    opencvsharp

    opencvsharp

    OpenCV wrapper for .NET

    OpenCV wrapper for .NET. Some Docker images are provided to use OpenCvSharp with AppEngine Flexible. The native binding (libOpenCvSharpExtern) is already built in the docker image and you don't need to worry about it. OpenCvSharp won't work on Unity and Xamarin platform. For Unity, please consider using OpenCV for Unity or some other solutions. OpenCvSharp does not support CUDA. If you want to use the CUDA features, you need to customize the native bindings yourself. Objects of classes, such as Mat and MatExpr, have unmanaged resources and need to be manually released by calling the Dispose() method. Worst of all, the +, -, *, and other operators create new objects each time, and these objects need to be disposed of, or there will be memory leaks. Despite the using syntax, the code still looks very verbose.
    Downloads: 5 This Week
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  • 9

    The Tao Framework

    Superseded by OpenTK: https://sourceforge.net/projects/opentk/

    The Tao Framework for .NET is a collection of bindings to facilitate cross-platform game-related development utilizing the .NET platform. Superseded by OpenTK: https://sourceforge.net/projects/opentk/
    Downloads: 28 This Week
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  • 10
    Xamarin.iOS & Xamarin.Mac

    Xamarin.iOS & Xamarin.Mac

    Bridges the worlds of .NET with the native APIs of macOS, iOS, tvOS

    Bridges the worlds of .NET with the native APIs of macOS, iOS, tvOS, and watchOS. This module is the main repository for both Xamarin.iOS and Xamarin.Mac. These SDKs allow us to create native iOS, tvOS, watchOS and macOS applications using the same UI controls we would in Objective-C and Xcode, except with the flexibility and elegance of a modern language (C#), the power of the .NET Base Class Library (BCL), and two first-class IDEs—Visual Studio for Mac and Visual Studio—at our fingertips. This repository is where we do development for the Xamarin.iOS and Xamarin.Mac SDKs. The preferred method for installing Xamarin.iOS and Mac is to use the Visual Studio installers (Windows, Mac). The team also strongly recommends using the latest Xamarin SDK and Xcode whenever possible.
    Downloads: 4 This Week
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  • 11
    xNode

    xNode

    Unity Node Editor: Lets you view and edit node graphs inside Unity

    Unity Node Editor: This lets you view and edit node graphs inside Unity. Thinking of developing a node-based plugin? Then this is for you. You can download it as an archive and unpack to a new unity project, or connect it as a git submodule. xNode is super userfriendly, and intuitive and will help you reap the benefits of node graphs in no time. With a minimal footprint, it is ideal as a base for custom state machines, dialogue systems, decision-makers, etc. No runtime reflection (unless you need to edit/build node graphs at runtime. In this case, all reflection is cached.) Custom node-inspector code is very similar to regular custom inspector code. Plugins are repositories that add functionality to xNode.
    Downloads: 4 This Week
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  • 12
    Castle aspires to simplify the development of enterprise and web applications. Offering a set of tools (working together or indepedently) and integration with other open source projects, Castle helps you get more done with less code.
    Downloads: 16 This Week
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  • 13
    Alchemi is a .NET grid computing framework that allows you to painlessly aggregate the computing power of intranet and Internet-connected machines into a virtual supercomputer (computational grid) and to develop applications to run on the grid.
    Downloads: 50 This Week
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  • 14
    File system/directory monitoring utilities with loggin and task processing support (can execute files or make a WCF service call). Multiple configuration options. Source code libraries can be used to create a custom file system monitor.
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    Downloads: 17 This Week
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  • 15
    IKVM.NET is a JVM for the Microsoft .NET Framework and Mono. It can both dynamically run Java classes and can be used to convert Java jars into .NET assemblies. It also includes a port of the OpenJDK class libraries to .NET.
    Downloads: 14 This Week
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  • 16
    .NET Multi-platform App UI

    .NET Multi-platform App UI

    .NET MAUI is the .NET Multi-platform App UI

    .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.
    Downloads: 3 This Week
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  • 17
    CoreCLR

    CoreCLR

    Runtime for .NET Core

    CoreCLR is the runtime for .NET Core, an open source, general purpose development platform maintained by Microsoft and the .NET community. It is a cross-platform runtime for cloud, IoT, and desktop apps and includes a just-in-time compiler called RyuJIT.
    Downloads: 3 This Week
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  • 18
    Coverlet

    Coverlet

    Cross platform code coverage for .NET

    Coverlet is a cross-platform code coverage framework for .NET, with support for line, branch and method coverage. It works with .NET Framework on Windows and .NET Core on all supported platforms. Coverlet documentation reflect the current repository state of the features, not the released ones. Check the changelog to understand if the documented feature you want to use has been officially released. Coverlet is integrated into the Visual Studio Test Platform as a data collector. Coverlet also integrates with the build system to run code coverage after tests. Enabling code coverage is as simple as setting the CollectCoverage property to true. The coverlet tool is invoked by specifying the path to the assembly that contains the unit tests. You also need to specify the test runner and the arguments to pass to the test runner using the --target and --targetargs options respectively.
    Downloads: 3 This Week
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  • 19
    MahApps.Metro

    MahApps.Metro

    Cobble together a better UI for their own WPF applications

    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.
    Downloads: 3 This Week
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  • 20
    Rules Engine

    Rules Engine

    A Json based Rules Engine with extensive Dynamic expression support

    A Json-based Rules Engine with extensive Dynamic expression support. RulesEngine is a highly extensible library to build a rule-based system using C# expressions. Rules Engine is a library/NuGet package for abstracting business logic/rules/policies out of a system. It provides a simple way of giving you the ability to put your rules in a store outside the core logic of the system, thus ensuring that any change in rules don't affect the core system. You need to store the rules based on the schema definition given and they can be stored in any store as deemed appropriate like Azure Blob Storage, Cosmos DB, Azure App Configuration, Entity Framework, SQL Servers, file systems, etc. For RuleExpressionType LamdaExpression, the rule is written as a lambda expression. Consuming Entity Framework and populating the Rules Engine is shown in the EFDemo class with Workflow rules populating the array and passed to the Rules Engine, The Demo App includes an example RulesEngineDemoContext.
    Downloads: 3 This Week
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  • 21
    SkiaSharp

    SkiaSharp

    SkiaSharp is a cross-platform 2D graphics API for .NET platforms

    SkiaSharp is a cross-platform 2D graphics API for .NET platforms based on Google's Skia Graphics Library. It provides a comprehensive 2D API that can be used across mobile, server and desktop models to render images. Building SkiaSharp is mostly straight forward. The main issue is the multiple dependencies for each platform. However, these are easy to install as they are found on the various websites. If you are just working on managed code, it is even easier as there mays to skip all the native builds. Because there are multiple distros of Linux, and we cannot possibly support them all, we have a separate NuGet package that will contain the supported binaries for a few distros.
    Downloads: 3 This Week
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  • 22
    STD Foundation Classes

    STD Foundation Classes

    Object oriented frameworks - PowerBuilder, PowerServer & InfoMaker!

    by Chris Pollach (http://chrispollach.blogspot.ca) A fully integrated "object oriented" set of PB Classes for the following products: PowerBuilder, PowerClient & PowerServer. The framework greatly enhances the development process by making the PowerBuilder developer significantly more productive! License: https://sourceforge.net/projects/stdfndclass/files/License (Open Source) => Updated version of the STD "Integrated" framework 2026R1 build 2026.1.0.467 was released to production on 2026-01-09. https://sourceforge.net/projects/stdfndclass/files/FrameWork/Integrated => The STD Framework "Example Apps" 2026 R1 latest builds https://chrispollach.blogspot.com/2026/03/updated.html => Updated version of the STD "Order Entry" example App 2025R2 build 2026.1.0.647 was released on 2026-04-08. https://sourceforge.net/projects/stdfndclass/files/Applications/PowerBuilder/OrderEntry
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    Downloads: 39 This Week
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  • 23
    Clean Architecture

    Clean Architecture

    Clean Architecture Solution Template

    A starting point for Clean Architecture with ASP.NET Core. Clean Architecture is just the latest in a series of names for the same loosely-coupled, dependency-inverted architecture. You will also find it named hexagonal, ports-and-adapters, or onion architecture. This architecture is used in the DDD Fundamentals course by Steve Smith and Julie Lerman. Contact Steve's company, NimblePros, for Clean Architecture or DDD training and/or implementation assistance for your team. After installing the template, you should be able to create a new project in Visual Studio and search for Clean Architecture. You should see the template appear in your list of project templates. Note that the template is generally only updated with major updates to the project. The GitHub repository will always have the latest bug fixes and enhancements.
    Downloads: 2 This Week
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  • 24
    Discord.Net

    Discord.Net

    An unofficial .Net wrapper for the Discord API

    Discord.Net is an asynchronous, multi-platform .NET Library used to interface with the Discord API. Nightlies are builds of Discord.NET that are still in an experimental phase, and have not been released. These are not included in the main repository and are instead taken over by Discord.NET Labs. Discord.NET Labs is an experimental fork of Discord.NET that implements the newest discord features for testing and development to eventually get merged into Discord.NET. A counterpart to the well-known command service of Discord.Net, the Interaction Framework implements the same feature-rich structure to register & handle interactions like application commands & buttons. Slash commands are purposed to take over the normal prefixed commands in Discord and come with good functionality to serve as a replacement. Being interactions, they are handled as SocketInteractions. Components of a message such as buttons and dropdowns, which can be interacted with and responded to.
    Downloads: 2 This Week
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  • 25
    Marten

    Marten

    .NET Transactional Document DB and Event Store on PostgreSQL

    The Marten library provides .NET developers with the ability to use the proven PostgreSQL database engine and its fantastic JSON support as a fully-fledged document database. The Marten team believes that a document database has far-reaching benefits for developer productivity over relational databases with or without an ORM tool. Marten also provides .NET developers with an ACID-compliant event store with user-defined projections against event streams. Use proven PostgreSQL database engine, its fantastic JSON support and ACID compliance as the underlying data store. A robust and full-fledged document database to boost your developer productivity. Build event-sourced style systems with ease to store events and streams. Use projections to create read-side views. Refer to the build commands section to look up the commands to run Mocha tests.
    Downloads: 2 This Week
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