An advanced, composable, functional reactive model-view-viewmodel framework for all .NET platforms that is inspired by functional reactive programming. ReactiveUI allows you to abstract mutable state away from your user interfaces, express the idea around a feature in one readable place and improve the testability of your application.
C# Other
Switch branches/tags
Permalink
Failed to load latest commit information.
.github added github issue/pr templates (#1140) Aug 12, 2016
packages revert: mintarget is no longer 460 as 452 is still supported (#1195) Nov 7, 2016
script Add script to nuke remote branches Dec 13, 2012
src chore: removed all obsolete UNIFIED symbol checks (#1303) May 23, 2017
tools/nuget bugfix: resolved issues with continuous integration pipeline Oct 25, 2016
.gitattributes updated .gitignore/.gitattributes from latest at github/gitignore Jan 23, 2016
.gitignore impl reactiveui-events nuget package creation Mar 27, 2016
.hgeol Merge (again). Jan 13, 2016
CODE_OF_CONDUCT.md chore: use hello@reactiveui.net for all communication (#1331) Apr 5, 2017
CONTRIBUTING.md [docs] added guidelines for new and existing contributors Aug 26, 2016
GitReleaseManager.yaml chore: added nuget.org release workflow (#1191) Nov 7, 2016
GitVersion.yml chore: removed next-version definition (#1238) Jan 31, 2017
LICENSE impl reactiveui-events nuget package creation Mar 27, 2016
README.md chore: use hello@reactiveui.net for all communication (#1331) Apr 5, 2017
appveyor.yml feature: enforce unit test coverage/enable coveralls (#1180) Jan 31, 2017
bootstrap.ps1 bugfix: resolved issues with continuous integration pipeline Oct 25, 2016
build.cake chore: failing to set the appveyor version should not be a fatal buil… Feb 4, 2017
build.cmd bugfix: resolved issues with continuous integration pipeline Oct 25, 2016
build.sh added bootstrap Mar 27, 2016

README.md

ReactiveUI Logo ReactiveUI

NuGet Stats #yourfirstpr Pull Request Stats Build status Coverage Status OpenCollective OpenCollective

Use the Reactive Extensions for .NET to create elegant, testable User Interfaces that run on any mobile or desktop platform. Supports Xamarin.iOS, Xamarin.Android, Xamarin.Mac, Xamarin Forms, WPF, Windows Forms, Windows Phone 8, Windows Store and Universal Windows Platform (UWP).

If you’re already familiar with functional reactive programming or what ReactiveUI is about, check out the documentation for more in-depth information about how it all works or our comprehensive collection of samples.

If you have a question, please see if any discussions in our GitHub issues or Stack Overflow have already answered it. If not, please feel free to file your own!

We have our very own Slack organization which contains some of the best user interface/reactive extension developers in the industry. All software engineers, young and old, regardless of experience are welcome to join our campfire but you'll need to send an email to hello@reactiveui.net with the email address you'd like to be invited, and we'll send you an invite. Sit tight, it's worth it.

Table of Contents

Introduction

ReactiveUI is inspired by functional reactive programming and is the father of the ReactiveCocoa (Cocoa/Swift) framework. Rather than using mutable variables which are replaced and modified in-place, ReactiveUI offers "event streams", represented by the IObserver and IObservable types, that send values over time.

If you are new to these concepts then we highly recommend watching the following videos before progressing too far:

Fundamentals

One of the most confusing aspects of the Reactive Extensions is that of "hot" and "cold" observables (event streams). In short, given just a method or function declaration like this:

IObservable<string> Search(string query)

It is impossible to tell whether subscribing to (observing) that IObservable will involve side effects. If it does involve side effects, it’s also impossible to tell whether each subscription has a side effect, or if only the first one does. Whilst this example is contrived, it demonstrates a real, pervasive problem that makes it harder at first for newcomers to understand Rx code at first glance.

As such we also recommend watching this video, reading our documentation and playing with the marbles to familiarize yourself with the fundamentals.

A Compelling Example

Let’s say you have a text field, and whenever the user types something into it, you want to make a network request which searches for that query.

public interface ISearchViewModel
{
    ReactiveList<SearchResults> SearchResults { get; }
    string SearchQuery { get; }	 
    ReactiveCommand<string, List<SearchResults>> Search { get; }
    ISearchService SearchService { get; }
}

Define under what conditions a network request will be made

// Here we're describing here, in a *declarative way*, the conditions in
// which the Search command is enabled.  Now our Command IsEnabled is
// perfectly efficient, because we're only updating the UI in the scenario
// when it should change.
var canSearch = this.WhenAny(x => x.SearchQuery, x => !String.IsNullOrWhiteSpace(x.Value));

Make the network connection

// ReactiveCommand has built-in support for background operations and
// guarantees that this block will only run exactly once at a time, and
// that the CanExecute will auto-disable and that property IsExecuting will
// be set accordingly whilst it is running.
Search = ReactiveCommand.CreateFromTask<string, List<SearchResults>>(_ => 
        searchService.Search(this.SearchQuery), canSearch);

Update the user interface

// ReactiveCommands are themselves IObservables, whose value are the results
// from the async method, guaranteed to arrive on the UI thread. We're going
// to take the list of search results that the background operation loaded, 
// and them into our SearchResults.
Search.Subscribe(results => {
    SearchResults.Clear();
    SearchResults.AddRange(results);
});

Handling failures

// ThrownExceptions is any exception thrown from the CreateAsyncTask piped
// to this Observable. Subscribing to this allows you to handle errors on
// the UI thread. 
Search.ThrownExceptions
    .Subscribe(ex => {
        UserError.Throw("Potential Network Connectivity Error", ex);
    });

Throttling network requests and automatic search execution behaviour

// Whenever the Search query changes, we're going to wait for one second
// of "dead airtime", then automatically invoke the subscribe command.
this.WhenAnyValue(x => x.SearchQuery)
    .Throttle(TimeSpan.FromSeconds(1), RxApp.MainThreadScheduler)
    .InvokeCommand(Search);

Slack

We have our very own Slack organization which contains some of the best user interface/reactive extension developers in the industry. All software engineers, young and old, regardless of experience are welcome to join our campfire but you'll need to send an email to hello@reactiveui.net with the Email address you'd like to be invited, and we'll send you an invite. Sit tight, it's worth it.

Support

ReactiveUI is an open source project that is community supported by people just like you. We keep a bunch of curated tasks specifically for new contributors which are a great way to get started with open source. They also provide a fantastic avenue for getting to know the ReactiveUI maintainers.

If you have a question, please see if any discussions in our GitHub issues or Stack Overflow have already answered it. If not, please feel free to file your own!

Contribute

Here are some pointers for anyone looking for mini-features and work items that would make a positive contribution to ReactiveUI.

We try not to be too OCD about coding style wars, but we do have our own convention and best design practices documented - please respect them and your pull-request experience will be much smoother. If you are using Visual Studio, please install the rebracer plugin which will automatically apply the correct source formatting settings.

We're also looking for people to assist with code reviews of ReactiveUI contributions. If you're experienced with any of the below technologies, you can join the team and receive notifications:

Showcase

We encourage our community to showcase where and how they have used ReactiveUI in their applications, some members have even gone as far as open-sourcing their app and sharing their entire codebase. You are of course under no-obligation share these insights (or code) with us but it is greatly appreciated by the project maintainers and you'll usually get a retweet out of it.

Licensing

The ReactiveUI project is licensed under the MS-PL license.

Sponsorship

Through contributions, donations, and sponsorship, you allow ReactiveUI to thrive. Your donations directly support meetups, office hours, continued enhancements, and most importantly, great documentation and learning material!

Backers

[Become a backer]

Sponsors

[Become a sponsor]