private async Task <bool> NavigateAndActivateAsync(Type viewModelType, object activationData)
{
var parameters = new DeactivationParameters(viewModelType, activationData);
if (!await this.DeactivatePreviousViewModelsAsync(NavigationType.Forward, viewModelType, parameters))
{
return(false);
}
var viewType = await this.viewLocator.GetViewTypeAsync(viewModelType);
var viewModel = await this.viewModelLocator.GetInstanceAsync(viewModelType);
var currentViewModel = this.ActiveViewModelType;
var currentView = currentViewModel != null ? await this.viewLocator.GetViewTypeAsync(currentViewModel) : null;
// activating the ViewModel instance
if (parameters.DeactivationData == null)
{
ViewModelActivator.ActivatingViewModel(viewModel, NavigationType.Forward);
}
else
{
ViewModelActivator.ActivatingViewModel(viewModel, NavigationType.Forward, parameters.DeactivationData);
}
// navigate to target View
this.platformNavigator.Navigate(viewType);
// push state
await this.statePersistor.PushStateAsync(viewModel, parameters.DeactivationData, this.platformNavigator.GetNavigationState());
this.ActiveViewModelType = viewModelType;
// raise navigated event
this.Navigated?.Invoke(this, new NavigationEventArgs(NavigationType.Forward, currentViewModel, currentView, viewModelType, viewType, parameters.DeactivationData));
// activate the ViewModel instance
if (parameters.DeactivationData == null)
{
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Forward);
}
else
{
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Forward, parameters.DeactivationData);
}
return(true);
}
private async Task <bool> GoBackAndActivateAsync(object deactivationData)
{
var nextState = (await this.statePersistor.GetAllStatesAsync()).Select(s => s).Reverse().Skip(1).First();
var parameters = new DeactivationParameters(nextState.ViewModelType, deactivationData);
if (!await this.DeactivatePreviousViewModelsAsync(NavigationType.Backward, null, parameters))
{
return(false);
}
var viewModel = await this.viewModelLocator.GetInstanceAsync(nextState.ViewModelType);
var viewType = await this.viewLocator.GetViewTypeAsync(nextState.ViewModelType);
var lastState = await this.statePersistor.PopStateAsync();
var lastViewType = await this.viewLocator.GetViewTypeAsync(lastState.ViewModelType);
// activating the ViewModelInstance
if (parameters.DeactivationData == null)
{
ViewModelActivator.ActivatingViewModel(viewModel, NavigationType.Backward);
}
else
{
ViewModelActivator.ActivatingViewModel(viewModel, NavigationType.Backward, parameters.DeactivationData);
}
// go back to previous View
this.platformNavigator.GoBack(lastState.ViewModelType, lastViewType);
this.ActiveViewModelType = nextState.ViewModelType;
// raise navigated event
this.Navigated?.Invoke(this, new NavigationEventArgs(NavigationType.Backward, lastState.ViewModelType, lastViewType, nextState.ViewModelType, viewType, parameters.DeactivationData));
// activate the ViewModel instance
if (parameters.DeactivationData == null)
{
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Backward);
}
else
{
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Backward, parameters.DeactivationData);
}
return(true);
}
public async Task RestoreApplicationStateAsync()
{
if (!await this.statePersistor.ContainsStateAsync())
{
return;
}
var states = await this.statePersistor.GetAllStatesAsync();
var lastState = states.Last();
var allViewTypes = await Task.WhenAll(states.Select(s => this.viewLocator.GetViewTypeAsync(s.ViewModelType)));
// this should also cause navigating to the last View, so no need to navigate there manually
this.platformNavigator.RestoreNavigationState(this.statePersistor.NavigationPath, allViewTypes);
foreach (var state in states.Where(s => s != null))
{
var viewType = await this.viewLocator.GetViewTypeAsync(state.ViewModelType);
var attribute = viewType.GetTypeInfo().GetCustomAttribute <AssociatedViewModelAttribute>();
var viewModel = await this.viewModelLocator.GetInstanceAsync(attribute.ViewModel);
var activationData = state.ActivationData;
var vmState = state.ViewModelState.Value;
// try to activate the ViewModel
if (activationData == null)
{
// TODO: when VM has StatePersistence set to None || StateOnly, this always gets called because activationData is set to null
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Forward);
}
else
{
ViewModelActivator.ActivateViewModel(viewModel, NavigationType.Forward, activationData);
}
this.statePersistor.SetViewModelState(viewModel, vmState);
}
}
