protected virtual IViewModel GetViewModelForView([NotNull] NavigationEventArgsBase args,
[CanBeNull] IViewModel navigationViewModel, [NotNull] INavigationContext context, [NotNull] Type vmType)
{
var view = args.Content;
if (navigationViewModel != null)
{
ViewManager.InitializeViewAsync(navigationViewModel, view, context);
return(navigationViewModel);
}
if (HasViewModel(view, vmType))
{
return((IViewModel)ToolkitExtensions.GetDataContext(view));
}
IDataContext viewModelState = null;
#if WINDOWS_UWP
viewModelState = UwpToolkitExtensions.GetViewModelState(view);
if (viewModelState != null)
{
UwpToolkitExtensions.SetViewModelState(view, null);
}
#endif
var vm = ViewModelProvider.RestoreViewModel(viewModelState, new DataContext
{
{ InitializationConstants.ViewModelType, vmType }
}, true);
if (vm != null)
{
ViewManager.InitializeViewAsync(vm, view, context);
if (viewModelState == null && !vm.Settings.Metadata.GetData(NavigationConstants.DoNotDisposeNoStateViewModel))
{
vm.RegisterNavigationOperation(OperationType.PageNavigation, context)
.ContinueWith <IViewModel>((viewModel, result) => viewModel.Dispose());
}
}
return(vm);
}
public void OnLoadState(FrameworkElement element, IDictionary <string, object> state, object args,
IDataContext context = null)
{
Should.NotBeNull(element, nameof(element));
Should.NotBeNull(state, nameof(state));
object value;
if (!state.TryGetValue(VmTypeKey, out value))
{
return;
}
state.Remove(VmTypeKey);
object dataContext = element.DataContext;
Type vmType = Type.GetType(value as string, false);
if (vmType == null || (dataContext != null && dataContext.GetType().Equals(vmType)))
{
return;
}
if (context == null)
{
context = DataContext.Empty;
}
var viewModelState = RestoreViewModelState(element, state, args, context);
//The navigation is already handled.
var eventArgs = args as NavigationEventArgs;
if (eventArgs != null && eventArgs.GetHandled())
{
eventArgs.SetHandled(false);
UwpToolkitExtensions.SetViewModelState(eventArgs.Content, viewModelState);
}
else
{
RestoreViewModel(vmType, viewModelState, element, state, args, context);
}
}
protected virtual IViewModel GetViewModelForView([NotNull] NavigationEventArgsBase args,
[CanBeNull] IViewModel navigationViewModel, [NotNull] INavigationContext context, [NotNull] Type vmType)
{
var view = args.Content;
if (navigationViewModel != null)
{
ViewManager.InitializeViewAsync(navigationViewModel, view, context);
return(navigationViewModel);
}
if (HasViewModel(view, vmType))
{
return((IViewModel)ToolkitExtensions.GetDataContext(view));
}
IDataContext viewModelState = null;
#if WINDOWS_UWP
viewModelState = UwpToolkitExtensions.GetViewModelState(view);
if (viewModelState != null)
{
UwpToolkitExtensions.SetViewModelState(view, null);
}
#endif
var vm = ViewModelProvider.RestoreViewModel(viewModelState, new DataContext
{
{ InitializationConstants.ViewModelType, vmType }
}, true);
if (vm != null)
{
ViewManager.InitializeViewAsync(vm, view, context);
}
return(vm);
}