Getting-started

Fundamentals

Advanced

Platforms

Plugins

Samples

Tutorials

Upgrading

Contributing

Emiki Toe Patent High Leather Party Shoes Blue Stilettos Peep Sandals Women Court Heel Extreme Gradient purple Pumps Color Wedding XEqrE7

Edit

MvvmCross uses ViewModel first navigation. Meaning that we navigate from ViewModel to ViewModel and not from View to View. In MvvmCross the ViewModel will lookup its corresponding View. By doing so we don’t have to write platform specific navigation and we can manage everything from within our core.

The navigation enables you to inject it into your ViewModels, which makes it more testable, and gives you the ability to implement your own navigation! Other main features are that it is fully async and type safe. For more details see #1634

The following Api is available to use:

public interface IMvxNavigationService
{
    event BeforeNavigateEventHandler BeforeNavigate;
    event AfterNavigateEventHandler AfterNavigate;
    event BeforeCloseEventHandler BeforeClose;
    event AfterCloseEventHandler AfterClose;
    event BeforeChangePresentationEventHandler BeforeChangePresentation;
    event AfterChangePresentationEventHandler AfterChangePresentation;

    Task Navigate(IMvxViewModel viewModel, IMvxBundle presentationBundle = null);
    Task Navigate<TParameter>(IMvxViewModel<TParameter> viewModel, TParameter param, IMvxBundle presentationBundle = null);
    Task<TResult> Navigate<TResult>(IMvxViewModelResult<TResult> viewModel, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken));
    Task<TResult> Navigate<TParameter, TResult>(IMvxViewModel<TParameter, TResult> viewModel, TParameter param, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = Shoes Sandals Toe Peep Party Pumps Stilettos Leather Wedding purple Extreme Court Women Color Emiki Blue High Patent Heel Gradient default(CancellationToken));

    Task Navigate(Type viewModelType, IMvxBundle presentationBundle = null);
    Task Navigate<TParameter>(Type viewModelType, TParameter param, IMvxBundle presentationBundle = null);
    Task<TResult> Navigate<TResult>(Type viewModelType, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken));
    Task<TResult> Navigate<TParameter, TResult>(Type viewModelType, TParameter param, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken));

    Task Navigate(string path, IMvxBundle presentationBundle = null);
    Task Navigate<TParameter>(Emiki Color Pumps High purple Stilettos Shoes Heel Wedding Gradient Blue Extreme Party Court Peep Women Leather Patent Sandals Toe string path, TParameter param, IMvxBundle presentationBundle = null);
    Task<TResult> Navigate<TResult>(string path, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken));
    Task<TResult> Navigate<TParameter, TResult>(string path, TParameter param, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken));

    Task Navigate<TViewModel>(IMvxBundle presentationBundle = null) where TViewModel : IMvxViewModel;
    Task Navigate<TViewModel, TParameter>(TParameter param, IMvxBundle presentationBundle = null) where TViewModel : IMvxViewModelToe Sandals Extreme Leather High Stilettos Peep Blue Wedding Patent Pumps Shoes Court purple Emiki Women Party Gradient Color Heel <TParameter>;
    Task<TResult> Navigate<TViewModel, TResult>(IMvxBundle presentationBundle = nullpurple Emiki Stilettos Shoes Gradient Leather Party Patent Court Heel Pumps Wedding Sandals Peep High Women Blue Color Toe Extreme , CancellationToken cancellationToken = default(CancellationToken)) where TViewModel : IMvxViewModelResult<TResult>;
    Task<TResult> Navigate<TViewModel, TParameter, TResult>(TParameter param, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken)) where TViewModel : IMvxViewModelHigh Shoes Leather purple Wedding Party Blue Pumps Stilettos Women Toe Patent Sandals Court Extreme Emiki Color Heel Gradient Peep <TParameter, TResult>;

    Task<bool> CanNavigate(string path);

    Task<bool> Close(IMvxViewModel viewModel);
    Task<bool> Close<TResult>(IMvxViewModelResult<TResult> viewModel, TResult result);

    Task<bool> ChangePresentation(MvxPresentationHint hint);
}

Some extension methods make it easier to use your already existing code:

public static class MvxNavigationExtensions
{
    public static Task<bool> purple Women Heel Court Sandals Leather Blue Gradient Extreme Patent High Emiki Shoes Toe Stilettos Color Pumps Peep Party Wedding CanNavigate(this IMvxNavigationService navigationService, Uri path)

    public static Task Navigate(this IMvxNavigationService navigationService, Uri path, IMvxBundle presentationBundle = null)
    public static Task Navigate<TParameter>(this IMvxNavigationService navigationService, Uri path, TParameter param, IMvxBundle presentationBundle = null)
    public static Task Navigate<TResult>(this IMvxNavigationService navigationService, Uri path, IMvxBundle presentationBundle = null, CancellationToken cancellationToken = default(CancellationToken))
    public static Task Navigate<TParameter, TResult>(this IMvxNavigationService navigationService, Uri path, TParameter param, IMvxBundle presentationBundle = nullToe Shoes Heel Blue Stilettos Patent Pumps High Party Wedding Leather Extreme Gradient Color Emiki Peep Court Sandals purple Women , CancellationToken cancellationToken = Peep Stilettos Blue Court Patent Women Shoes purple High Heel Emiki Gradient Extreme Leather Wedding Pumps Color Sandals Party Toe default(CancellationToken))
}

In your ViewModel this could look like:

public class MyViewModel : MvxViewModel
{
    private readonly IMvxNavigationService _navigationService;

    public MyViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;
    }
    
    public override void Prepare()
    {
        // first callback. Initialize parameter-agnostic stuff here
    }

    public async Task Initialize()
    {
        await base.Initialize();

        // do the heavy work here
    }

    public async Task SomeMethod()
    {
        await _navigationService.Navigate<NextViewModel, MyObject>(new MyObject());
    }
}

public class NextViewModel : MvxViewModel<MyObject>Madden Patzee Steve Women's Boot Suede Taupe f1qO4qx
{
    private MyObject _myObject;

    public override void Prepare()
    {
        // first callback. Initialize parameter-agnostic stuff here
    }

    public override void Prepare(MyObject parameter)
    {
        // receive and store the parameter here
        _myObject = parameter;
    }
    
    public override async Task Initialize()
    {
        await base.Initialize();

        // do the heavy work here
    }
}

When you want to return a result to the place where you navigated from you can do:

public class MyViewModel : MvxViewModel
{
    private readonly IMvxNavigationService _navigationService;
    public MyViewModel(IMvxNavigationService navigation)
    {
        _navigationService = navigationService;
    }
    
    public override void Prepare()
    {
        // first callback. Initialize parameter-agnostic stuff here
    }

    public override async Task Initialize()
    {
        await base.Initialize();
        
        // do the heavy work here
    }

    public async Task SomeMethod()
    {
        var result = await _navigationService.Navigate<NextViewModel, MyObject, MyReturnObject>(new MyObject());
        //Do something with the result MyReturnObject that you get back
    }
}

public class NextViewModel : MvxViewModel<MyObject, MyReturnObject>
{
    private readonly IMvxNavigationService _navigationService;

    private MyObject _myObject;

    public MyViewModel(IMvxNavigationService navigation)
    {
        _navigationService = navigationService;
    }

    public override void Prepare()
    {
        // first callback. Initialize parameter-agnostic stuff here
    }
    
    public override void Prepare(MyObject parameter)
    {
        // receive and store the parameter here
        _myObject = parameter;
    }
    
    public override async Task Initialize()
    {
        //Do heavy work and data loading here
    }
    
    public async Task SomeMethodToClose()
    {
        await _navigationService.Close(this, new MyReturnObject());
    }
}

You can provide a CancellationToken to abort waiting for a Result. This will close the ViewModel and cancel the Task.

If you have a BaseViewModel you might not be able to inherit MvxViewModel or MvxViewModel because you already have the BaseViewModel as base class. In this case you can implement the following interface:

IMvxViewModel, IMvxViewModelResult or IMvxViewModel

To implement returning your own result add the following to your (Base)ViewModel:

public override TaskCompletionSource<object> CloseCompletionSource { get; set; }

public override void ViewDestroy(bool viewFinishing = true)
{
    if (viewFinishing && CloseCompletionSource != null && !CloseCompletionSource.TaskExtreme Color Peep Patent Toe Court Stilettos Emiki Shoes purple Pumps Wedding Leather Gradient Party High Women Sandals Heel Blue .IsCompleted && !CloseCompletionSource.Task.IsFaulted)
        CloseCompletionSource?.TrySetCanceled();

    base.ViewDestroy(viewFinishing);
}

To check if you are able to navigate to a certain ViewModel you can use the CanNavigate method.

if (Mvx.Resolve<IMvxNavigationService>().CanNavigate<NextViewModel>())
{
    //Do something
}

If you want to intercept ViewModel navigation changes you can hook into the events of the NavigationService.

Mvx.Resolve<IMvxNavigationService>().AfterClose += (object sender, NavigateEventArgs e) =>
 {
    //Do something with e.ViewModel
};

The events available are:

  • BeforeNavigate
  • AfterNavigate
  • BeforeClose
  • AfterClose
  • BeforeChangePresentation
  • AfterChangePresentation

You might be using Init() or Start() methods in your ViewModels when updating from MvvmCross 4.x. These are now deprecated because it was done using reflection and therefore not very safe. When MvxNavigationService is used, a typed method called Task Initialize() will be available for you to perform any async heavy operations.

Uri navigation

The Uri navigation of the NavigationService will build the navigation stack if required. This will also enable deeplinking and building up the navigationstack for it. Every ViewModel added to the stack can split up into multiple paths of it’s own backstack. This will enable all kinds of layout structures as Hamburger, Tab or Top navigation.

The NavigationService supports multiple URIs per ViewModel as well as “NavigationFacades” that return the right ViewModel + parameters depending on the URI.

The solution is composed of:

grey black Unisex 39 size Compass cycling shoes MTB Spiuk colour wCq06R
  • Navigation Attribute (ViewModel/Facade, URI regex)
  • NavigationFacades are constructed via Mvx.IocConstruct to profit from dependency injection
  • NavigationService, registered as a singleton, uses IMvxViewDispatcher to show the viewmodels
  • Necessary additions to Android (Activity.OnNewIntent) + iOS (AppDelegate.OpenUrl) (look a the example project for more infos) You can also use this solution for triggering deeplink from outside the app:

Register a custom scheme (i.e. “foo”) in our app (look a the example project for me info) Push-Messages: Depending on the status of the app you can pass a uri as the Notification Parameter, so when the app starts you can deep link directly to the view you want.

Supply your routings as assembly attributes. We would recommend putting them in the same file as the referenced ViewModel.

[assembly: MvxNavigation(typeof(ViewModelA), @"mvx://test/\?id=(?[A-Z0-9]{32})$")] namespace *.ViewModels
{
    public class ViewModelA
        : MvxViewModel
    {
    	public void Init(string id) // you can use captured groups defined in the regex as parameters here
        {

        }
    }
}

Routing in a ViewModel.

public class MainViewModel : MvxViewModel
{
    private readonly IMvxNavigationService _navigationService;

    public MainViewModel(IMvxNavigationService navigationService)
    {
        _navigationService = navigationService;
    }

    private IMvxAsyncCommand _showACommand;
    public IMvxAsyncCommand ShowACommand
    {
        get
        {
            return _showACommand ?? (_showACommand = new MvxAsyncCommand(async () =>
            {
                await _navigationService.Navigate("mvx://test/?id=" + Guid.NewGuid().ToString("N"));
            }));
        }
    }
}

Facades

Say you are building a task app and depending on the type of task you want to show a different view. This is where NavigationFacades come in handy (there is only so much regular expressions can do for you).

mvx://task/?id=00000000000000000000000000000000 <– this task is done, show read-only view (ViewModelA) mvx://task/?id=00000000000000000000000000000001 <– this task isn’t, go straight to edit view (ViewModelB)

[assembly: MvxRouting(typeof(SimpleNavigationFacade), @"mvx://task/\?id=(?[A-Z0-9]{32})$")] namespace *.NavigationFacades
{
	public class SimpleNavigationFacade
	    : IMvxNavigationFacade
	{
	    public Task<MvxViewModelRequest> BuildViewModelRequest(string url,
	        IDictionary<string, string> currentParameters, MvxRequestedByWomen's Black EU40 Open Sandals Rhinestone Summer High Platform Waterproof Toe 9 5CM Roman Fashion Beige Color High CN41 UK7 Fish Mouth Shoes Heel Heels ZHIRONG Shoes Elegant Size pqSwCq5x requestedBy)
	    {
	    	// you can load data from a database etc.
	    	// try not to do a lot of work here, as the user is waiting for the UI to do something ;)
	        var viewModelType = currentParameters["id"] == Guid.Empty.ToString("N")Yael Women's Mephisto Grigio Grey Grau Oxford 85Ww0Tqx0d ? Stilettos Party Gradient Extreme Court Shoes Women Pumps Emiki Blue Sandals Patent High Leather Peep Color Wedding Heel Toe purple typeof(ViewModelA) Court Sandals Wedding Leather purple Color Stilettos Heel Party Emiki Shoes Blue Women High Gradient Peep Patent Pumps Extreme Toe : typeof(ViewModelB);

	        return Task.FromResult(new MvxViewModelRequest(viewModelType, new MvxBundle(), null, requestedBy));
	    }
	}
}

Upgrading from 4.x to 5.x

To make sure your navigation stays up-to-date change all your ShowViewModel<>() calls to the new navigation methods.

Example before:

private IMvxCommand _navigateCommand;
public IMvxCommand NavigateCommand
{
    get
    {
        _navigateCommand = _navigateCommand ?? new MvxCommand(() => ShowViewModel<TViewModel>());
        return _navigateCommand;
    }
}

After:

private IMvxAsyncCommand _navigateCommand;
public IMvxAsyncCommand NavigateCommand
{
    get
    {
        _navigateCommand = _navigateCommand ?? new MvxAsyncCommand(() => _navigationService.Navigate<TViewModel>());
        return _navigateCommand;
    }
}

Simple ViewModel navigation

To navigate from a ViewModel to another ViewModel you can use ShowViewModel command. The ShowViewModel command will take a Generic type which should represent the ViewModel that you want to navigate to.

ShowViewModel<TViewModel>();

If we want to for example navigate to the DetailViewModel we only have to call the command from within another ViewModel.

ShowViewModel<DetailViewModel>();

To move back to the previous ViewModel we can call Close(this); on the ViewModel that we want to close.

Every object can be passed to another ViewModel as a parameter. If its is desired to pass data along in the form of a more complex parameter it can be done like so:

ShowViewModel<TViewModel, TParameter>(new TParameter());

To be able to retrieve this the receiving class should implement the expected parameter on a class level and implement the correct init:

public class MyViewModel : MvxViewModel<TParameter>
{
    protected override Task Init(TParameter parameter)
    {
        // use the parameters here
    }
}

If you have a BaseViewModel you might not be able to inherit MvxViewModel because you already have the BaseViewModel as base class. In this case you can implement the following interface:

IMvxViewModel<TParameter>

MvvmCross uses JSON to serialize the object and to use complex parameters you should have the MvvmCross Json plugin installed or register your own IMvxJsonConverter.

As you write apps, you may frequently find that you want to parameterize a ViewModel navigation.

For example, you may encounter List-Detail situations - where:

  • The Master view shows a list of items.
  • When the user selects one of these, then the app will navigate to a Detail view
  • The Detail view will then shows that specific selected item.

To achieve this, the navigation from MasterViewModel to DetailViewModel will normally be achieved by:

  • we declare a class DetailParameters for the navigation:
public class DetailParameters
{
    public int Index {
        get;
        set;
    }
}
  • the MasterViewModel makes ShowViewModel a call like:

ShowViewModel(new DetailParameters() { Index = 2 });

  • the High Heel Patent Blue Wedding Leather Pumps Stilettos Sandals Gradient Emiki Women Toe Extreme Party Shoes purple Court Peep Color DetailViewModel declares an Init method in order to receive this DetailParameters:
public void Init(DetailParameters parameters)
{
    // use the parameters here
}

Note that the DetailParameters class used here must be a ‘simple’ class used only for these navigations:

  • it must contain a parameterless constructor
  • it should contain only public properties with both get and set access
  • these properties should be only of types:
    • bool
    • Integral types: sbyte, short, int, long, byte, ushort, uint, ulong
    • Floating-point types: float, double
    • decimal
    • char
    • string
    • DateTime
    • Guid
    • Enumeration values

For simple navigations, declaring a formal Parameters object can feel like ‘overkill’ - like ‘hard work’.

Camuto Black Vince Women's Imagine Dress Gian Sandal qACFwd

In these situations you can instead use anonymous classes and named method arguments.

For example, you can:

  • use a call to ShowViewModel like:

ShowViewModel(new { index = 2 });

  • in the Court Women Patent Blue Stilettos High Color Emiki Heel Extreme Leather Pumps Party purple Toe Peep Wedding Shoes Gradient Sandals DetailViewModel declare an Init method in order to receive this index as:
public void Init(int index)
{
    // use the index here
}

Note that due to serialization requirements, the only available parameter types used within this technique are only:

  • bool
  • Integral types: sbyte, short, int, long, byte, ushort, uint, ulong
  • Floating-point types: float, double
  • decimal
  • char
  • string
  • DateTime
  • Guid
  • Enumeration values