Xamarin.Forms.MVVMBase
Simple MVVM framework for Xamarin.Forms projects
This is the component, works on iOS, Android.
NuGet
| Name | Info |
|---|---|
| Xamarin.Forms.MVVMBase |
Platform Support
Xamarin.Forms.MVVMBase is a .NET Standard 2.0 library.Its dependencies are Xamarin.Forms and Microsoft Extensions for iOC
Initialize
App.cs :
public partial class App : Application
{
public App()
{
InitializeComponent();
BuildDependencies();
InitNavigation();
}
public void BuildDependencies()
{
Container.Current.RegisterForNavigation<MainPage, MainViewModel>();
//Configure Container
Container.Current.Setup();
}
async void InitNavigation()
{
var navigationService = Container.Current.Resolve<INavigationService>();
//Basic Startup
await navigationService.InitializeAsync<MainViewModel>(null, true);
}
}Determines which Initial ViewModel of your app :
InitializeAsync<MainViewModel>(null, true)To register the View Matching ViewModel, use:
Container.Current.RegisterForNavigation <View, ViewModel> ();Base ViewModel
BaseViewModel is based on all ViewModels. BaseViewModel Implements LoadAsync in addition to Navigation and Dialog Service
public class MainViewModel : BaseViewModel
{
//Set Title
public MainViewModel() : base("Main View")
{
}
//Override Load
public override async Task LoadAsync(NavigationParameters navigationData)
{
}
//Override OnNavigate
public override async Task OnNavigate(NavigationParameters navigationData)
{
if (navigationData.NavigationState == NavigationState.Backward)
{
//you can use the navigation to identify whether you have returned from a viewmodel
}
if (navigationData.NavigationState == NavigationState.Forward)
{
//you can use the navigation to identify whether you have navigated to a viewmodel
}
}
}BaseViewModel already behind the implementations of Title and isBusy by default to use in all views
Navigation
Use BaseViewModel NavigationService to navigate between them. You can also send parameters that will be received in LoadAsync.
await NavigationService.NavigateToAsync<DetalhesViewModel>();
await NavigationService.NavigateToAsync<DetalhesViewModel>(parameter);NavigationParameters can be used to send parameters to a View, both when navigating to a new one and returning to the previous one.
var parametros = new NavigationParameters();
parametros.Add("key", value);navigationData also returns if it is a new navigation or return from some view. use NavigationState :
public enum NavigationState
{
Init, //Start App
Forward, //Navigation to next View
Backward // Return Navigation
}In addition to object navigation you can also browse via queryString as if using a url :
NavigationParameters(string queryString)
Dialog
Use BaseViewModel DialogService to display custom alerts or an actionsheet.
//Alert
await DialogService.AlertAsync("Title", "Message", "Cancel Button Label");
//Dialog
await DialogService.AlertAsync("Title", "Message", "Accept Button Label", "Cancel Button Label");
//ActionSheet
await DialogService.ActionSheetAsync("Title", "Message", "Destruction Button Label", buttons);BasePage
You can use BasePage instead of the standard ContentPage. BasePage automatically changes the title to that of BaseViewModel and also implements DeepLink
/<?xml version="1.0" encoding="utf-8"?>
<base:BasePage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:d="http://xamarin.com/schemas/2014/forms/design"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:base="clr-namespace:Xamarin.Forms.MVVMBase.Page;assembly=Xamarin.Forms.MVVMBase"
mc:Ignorable="d">
</base:BasePage>
public void OnAppLinkRequestReceived(Uri uri)
Dependency Injection
Xamarin.Forms.MVVMBase uses DryIoc. You can use your container in the app.cs with :
Container.Current.Register<Interface, Implementation> (LifeTime.Singleton);Use the lifetime for your IoC
public enum LifeTime
{
Scoped,
Singleton,
Transient
}