public virtual void OnNavigated(NavigationEventArgsBase e)
{
EventHandler<INavigationService, NavigationEventArgsBase> handler = Navigated;
if (handler != null) handler(this, e);
}
private void UpdateNavigationContext(IOperationCallback callback, IViewModel navigationViewModel, NavigationEventArgsBase args, ref INavigationContext context)
{
var vmType = context.GetData(ViewModelTypeConstant);
if (vmType == null)
return;
var viewModel = GetViewModelForView(args, navigationViewModel, context, vmType);
if (!ReferenceEquals(context.ViewModelTo, viewModel))
context = new NavigationContext(NavigationType.Page, context.NavigationMode, context.ViewModelFrom, viewModel, context.NavigationProvider);
if (viewModel != null && callback != null)
RegisterOperationCallback(viewModel, callback, context);
}
protected virtual INavigationContext CreateContextNavigateTo(IViewModel viewModelFrom, NavigationEventArgsBase args)
{
string idOperation;
var vmType = GetViewModelTypeFromParameter(NavigationService.GetParameterFromArgs(args), out idOperation);
var viewModelTo = idOperation == _currentOperationId ? _navigationTargetVm : null;
if (vmType == null)
{
if (args.Content != null)
{
var items = _mappingProvider.FindMappingsForView(args.Content.GetType(), false);
if (items.Count == 1)
{
var type = items[0].ViewModelType;
#if WINDOWSCOMMON || XAMARIN_FORMS
if (!type.GetTypeInfo().IsGenericTypeDefinition)
#else
if (!type.IsGenericTypeDefinition)
#endif
vmType = type;
}
}
if (vmType == null)
return new NavigationContext(NavigationType.Page, args.Mode, viewModelFrom, viewModelTo, this)
{
{NavigationArgsConstant, args},
{OperationIdConstant, idOperation}
};
}
return new NavigationContext(NavigationType.Page, args.Mode, viewModelFrom, viewModelTo, this)
{
{NavigationArgsConstant, args},
{ViewModelTypeConstant, vmType},
{OperationIdConstant, idOperation}
};
}
/// <summary>
/// Subscriber to the Navigated event.
/// </summary>
protected virtual void NavigationServiceOnNavigated(object sender, NavigationEventArgsBase e)
{
string idOperation = null;
try
{
var context = CreateContextNavigateTo(CurrentViewModel, e);
idOperation = context.GetData(OperationIdConstant);
IOperationCallback callback = null;
if (idOperation == _currentOperationId)
{
callback = _currentCallback;
_currentCallback = null;
_navigationTargetVm = null;
_lastContext = null;
}
UpdateNavigationContext(callback, context.ViewModelTo, e, ref context);
OnNavigated(context);
}
finally
{
if (idOperation == _currentOperationId)
{
_currentOperationId = null;
var tcs = _navigatedTcs;
if (tcs != null)
{
_navigatedTcs = null;
tcs.TrySetResult(null);
}
}
}
}
private void RaiseNavigated(NavigationEventArgsBase args)
{
var handler = Navigated;
if (handler != null)
handler(this, args);
}
private void RaiseNavigated(NavigationEventArgsBase args)
{
Navigated?.Invoke(this, args);
}
