Search

Drop Down MenusCSS Drop Down MenuPure CSS Dropdown Menu

Thursday, September 26, 2019

Building a Cross Platform MVVM Pattern with ReactiveUI and Xamarin.Forms


As a Mobile Developer, when we start a new project, we always search and speak about application architecture. One of the most common choices in Xamarin.Forms is MVVM, this is due to the small amount of work to implement it, if we use ReactiveUI, we can additionally write applications in a reactive manner. It’s a time to check reactive UI how we can implement in Xamairn Forms project.
Reactive Extensions have been around for many years, and is available to most development environments. In this post, we are specifically going to look at Rx in terms of .NET development in Xamarin Forms. 
Rx is just a library for composing asynchronous, and event-based code with observables, and configuring it via LINQ. You can use LINQ to define criteria of when you want to perform an action, on the event. Rx can do more, but we will only look at the very basics in this post.
ReactiveUI allows you to combine the MVVM pattern with Reactive Programming using such features, as WhenAnyValue, ReactiveCommand, ObservableAsPropertyHelper, Binding and WhenActivated.
Create New Xamarin.Forms Application
In order to learn the ReactiveUI, let’s start creating a new Xamarin.Forms project using Visual Studio 2019 or VS for Mac. When using Visual Studio 2019 on a Windows machine, you will need to pair the mac machine for run and build the iOS platform.


Open Visual Studio 2019 >>Create a New Project or select "Open Recent Application" and the available templates will appear on a Windows like below. Select Xamarin.Form app and click on “Next”


ReactiveUI Nuget Package:
To implement ReactiveUI in our applications we will need to install the library. 
Step 1: Right click on Project and Click on Manage NuGet Packages for Solution option. 
Step 2: Search for “ReactiveUI.XamForms”.
Step 3: Install it for all of our projects with each platform. 


Create ViewModel :
ReactiveUI syntax for read-write properties is to notify Observers that a property has changed. Otherwise we would not be able to know when it was changed.
  • In cases when we don't need to provide for two-way binding between the View and the ViewModel, we can use one of many ReactiveUI Helpers, to notify Observers of a changing read-only value in the ViewModel.
  • RaiseAndSetIfChanged fully implements a Setter for a read-write property on a ReactiveObject, using CallerMemberName to raise the notification and the ref to the backing field to set the property.
  • ReactiveCommand is a Reactive Extensions and asynchronous aware implementation of the ICommand interface. ICommand is often used in the MVVM design pattern to allow the View to trigger business logic defined in the ViewModel
Let we create following property and command in the following ViewModel 
using System;
using System.Threading.Tasks;
using ReactiveUI;
using System.Reactive;
using System.Text.RegularExpressions;
using System.Collections.Generic;
using System.Reactive.Linq;

namespace ReactiveUIXamarin.ViewModel
{
    public class MainPageViewModel: ReactiveObject
    {
        private string _result;
        public string Result
        {
            get => _result;
            set => this.RaiseAndSetIfChanged(ref _result, value);
        }
        private string _username;
        public string UserName
        {
            get => _username;
            set => this.RaiseAndSetIfChanged(ref _username, value);
        }
        private string _password;
        public string Password
        {
            get => _password;
            set => this.RaiseAndSetIfChanged(ref _password, value);
        }
        private string _address;
        public string Address
        {
            get => _address;
            set => this.RaiseAndSetIfChanged(ref _address, value);
        }
        private string _phone;
        public string Phone
        {
            get => _phone;
            set => this.RaiseAndSetIfChanged(ref _phone, value);
        }
        public ReactiveCommand<Unit, Unit> RegisterCommand { get; }

        public MainPageViewModel()
        {
            RegisterCommand = ReactiveCommand
                .CreateFromObservable(ExecuteRegisterCommand);
        }

        private IObservable<Unit> ExecuteRegisterCommand()
        {
            Result = "Hello" + UserName + " Registration Success";
            return Observable.Return(Unit.Default);
        }
    }
  
}


Create UI View:
ReactiveUI allows you to create views using two different approaches. The recommended approach is using type-safe ReactiveUI bindings that can save you from memory leaks and runtime errors. The second approach is using XAML markup bindings.
The following sample UI created by recommended approach using type-safe ReactiveUI .
<rxui:ReactiveContentPage
  x:Class="ReactiveUIXamarin.MainPage"
  x:TypeArguments="vm:MainPageViewModel"          
  xmlns:vm="clr-namespace:ReactiveUIXamarin.ViewModel;assembly=ReactiveUIXamarin"
  xmlns:rxui="clr-namespace:ReactiveUI.XamForms;assembly=ReactiveUI.XamForms"
  xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
  xmlns:ios="clr-namespace:Xamarin.Forms.PlatformConfiguration.iOSSpecific;assembly=Xamarin.Forms.Core" 
  xmlns="http://xamarin.com/schemas/2014/forms"
    ios:Page.UseSafeArea="true">
    <StackLayout>
        <Entry x:Name="Username" Placeholder="Username"/>
        <Entry x:Name="Password" Placeholder="Password"  />
        <Entry x:Name="Address" Placeholder="Address"  />
        <Entry x:Name="Phone" Placeholder="Phone Number" />
        <Button x:Name="Register" Text="Register" TextColor="White" BackgroundColor="Gray" />
        <Label x:Name="Result" />
    </StackLayout>
</rxui:ReactiveContentPage>


  • ContentPage should inherit from ReactiveContentPage<TViewModel> and we are going to use ReactiveUI Binding to bind our ViewModel to our View. 
  • Reactive binding is a cross platform way of consistently binding properties on your ViewModel to controls on your View. 
  • The ReactiveUI binding has a few advantages over the XAML based binding. The first advantage is that property name changes will generate a compile error rather than runtime errors.
  • One important think needs to follows while Binding, always dispose bindings via WhenActivated, or else the bindings leak memory.
using ReactiveUI;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using ReactiveUIXamarin.ViewModel;
using ReactiveUI.XamForms;
using System.Reactive.Disposables;

namespace ReactiveUIXamarin
{

    public partial class MainPage : ReactiveContentPage<MainPageViewModel>
    {
        public MainPage()
        {
            InitializeComponent();
            ViewModel = new MainPageViewModel();

            // Setup the bindings.
            // Note: We have to use WhenActivated here, since we need to dispose the
            // bindings on XAML-based platforms, or else the bindings leak memory.
            this.WhenActivated(disposable =>
            {
                this.Bind(ViewModel, x => x.UserName, x => x.Username.Text)
                    .DisposeWith(disposable);
                this.Bind(ViewModel, x => x.Password, x => x.Password.Text)
                    .DisposeWith(disposable);
                this.Bind(ViewModel, x => x.Address, x => x.Address.Text)
                   .DisposeWith(disposable);
                this.Bind(ViewModel, x => x.Phone, x => x.Phone.Text)
                   .DisposeWith(disposable);
                this.BindCommand(ViewModel, x => x.RegisterCommand, x => x.Register)
                  
                    .DisposeWith(disposable);
                this.Bind(ViewModel, x => x.Result, x => x.Result.Text)
                   .DisposeWith(disposable);
            });
        }
    }
}


Output:
You can download the source code from github repository. When you run the application in an iPhone device, you will get the following output and click on Register, it will show the confirmation message like below screen.
Summary
This article has demonstrated and covers a little bit of what you can do when you combine the power of Reactiveui in Xamarin.Forms. I hope this article will help you to get started with awesome Framework.

18 comments:

  1. Replies
    1. Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download Now

      >>>>> Download Full

      Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download LINK

      >>>>> Download Now

      Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download Full

      >>>>> Download LINK 3k

      Delete
  2. Change is the only constant. This applies in your professional life as well as personal life. Up-scaling yourself is a need nowadays, the reason is pretty simple, technology is evolving very quickly. I have listed top 10 trending technologies, which is expected to acquire a huge market in 2020.

    1. AI (Artificial Intelligence)
    2. Blockchain
    3. Augmented Reality and Virtual Reality
    4. Cognitive Cloud Computing
    5. Angular and React
    6. DevOps
    7. IoT (Internet of Things)
    8. Intelligent Apps (I – Apps)
    9. Big Data
    10. RPA (Robotic Process Automation)

    ReplyDelete
  3. Xamarin app development is a cost effective solution to build fast and resoponsive web application go through Xamarin App Development Company

    ReplyDelete
    Replies
    1. Once again. How about finding some other way to advertise your company.

      Delete
  4. Maybe you should find some other way to advertise you company.

    ReplyDelete
  5. Nice and interesting post, I appreciate your hard work. keep it up…!!!

    Want to make custom website & application? Click here:
    Mobile Application Development
    Android Application Development
    iOS Application Development

    ReplyDelete
  6. Among many feature-packed mobile ap platforms, Xamarin development is a trending cross-platform framework. Xamarin facilitates Native like performance and makes it possible to access each and every native API.

    ReplyDelete
  7. Numerous organizations overall consider the alternative of a circulated committed group model in their business. This recruiting technique gives you an adaptable labor force that can be added or decreased, your group commitment in your venture, 24 hours workday, quicker issues goal, obligation, high mastery and sensible expenses. It is feasible to set aside to half of work exchange and an on location. All in all, it gives considerably more advantages to your business as opposed to on the off chance that you'd decide to employ specialists. Outstaffing is recruiting web engineers abroad from an nearshore and offshore development firm. Recruit offshore staff, and you can continue to work with similar group on additional undertakings. Building up a business dependent on reevaluating is definitely not a serious deal, it assists with setting aside cash and time and is not difficult to execute. Because of an assortment of offshore development models accessible, everybody can discover an alternative that fits him best. The offshore development model is ideal for organizations that know about the downsides of task the executives and programming development gives that may emerge during work. These organizations frequently focus on cost decrease keeping the nature of the item and are prepared to put resources into long haul business relations.

    ReplyDelete
  8. Businesses are now looking to develop their services with leading cross platform app development. This blog guides well on for to look into making the considerations for mobile app development with cross platform framework for app. We can get the solutions in Flutter app development, Android app development, iOS App Development

    ReplyDelete
  9. Apps have now taken over the conventional brick and mortar stores as the new millennials want to order everything online.
    On Demand App Development

    ReplyDelete
  10. Get the best of leading solutions in mobile app development blockchain app development and IoT Development that allows your business to scale up with leading technological advancements.

    ReplyDelete
  11. Hey! I agree with the commentators, a very useful article. In gratitude, I would like to advise you on one web page. It will be of interest to Java Script developers, because they have indicated the qualities and characteristics that they pay the most attention to when hiring, and a lot of other interesting information.

    ReplyDelete
  12. Our react native app development team create a slick, smooth and responsive user interface with lower load time. So, if you have an app idea For android, android TV, iOS, macOS, or other platform? Lets discuss with us!

    ReplyDelete
  13. This comment has been removed by the author.

    ReplyDelete
  14. Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download Now

    >>>>> Download Full

    Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download LINK

    >>>>> Download Now

    Devenvexe.Com/Xamarin: Building A Cross Platform Mvvm Pattern With Reactiveui And Xamarin.Forms >>>>> Download Full

    >>>>> Download LINK 2O

    ReplyDelete