private static CachedViewModel GetOrAddCachedViewModel(Guid id)
{
lock (CachedViewModels)
{
CachedViewModel value;
if (!CachedViewModels.TryGetValue(id, out value))
{
value = new CachedViewModel();
CachedViewModels[id] = value;
}
return(value);
}
}
public IViewModel RestoreViewModel(IDataContext viewModelState, IDataContext dataContext, bool throwOnError)
{
try
{
dataContext = dataContext.ToNonReadOnly();
if (viewModelState == null)
{
viewModelState = DataContext.Empty;
}
else
{
dataContext.Merge(viewModelState);
}
IViewModel viewModel;
if (!dataContext.GetData(InitializationConstants.IgnoreViewModelCache))
{
Guid id;
if (viewModelState.TryGetData(ViewModelConstants.Id, out id))
{
viewModel = GetOrAddCachedViewModel(id).GetViewModel();
if (viewModel != null)
{
return(viewModel);
}
}
}
CachedViewModel restoredParentViewModel = null;
IViewModel parentViewModel = null;
Guid idParent;
if (viewModelState.TryGetData(ViewModelConstants.IdParent, out idParent))
{
restoredParentViewModel = GetOrAddCachedViewModel(idParent);
parentViewModel = restoredParentViewModel.GetViewModel();
if (parentViewModel != null)
{
dataContext.AddOrUpdate(InitializationConstants.ParentViewModel, parentViewModel);
}
}
var restoring = Restoring;
if (restoring != null)
{
var args = new ViewModelRestoringEventArgs {
Context = dataContext, State = viewModelState
};
restoring(this, args);
dataContext = args.Context ?? DataContext.Empty;
}
viewModel = RestoreViewModelInternal(viewModelState, dataContext);
if (viewModel != null)
{
if (restoredParentViewModel != null && parentViewModel == null)
{
restoredParentViewModel.AddChildViewModel(viewModel);
}
OnViewModelRestored(viewModel, viewModelState, dataContext);
var restored = Restored;
if (restored != null)
{
var args = new ViewModelRestoredEventArgs(viewModel)
{
Context = dataContext,
State = viewModelState
};
restored(this, args);
}
Tracer.TraceViewModel(ViewModelLifecycleType.Restored, viewModel);
if (ReferenceEquals(viewModelState, DataContext.Empty))
{
Tracer.Warn("The view model '{0}' was restored without state.", viewModel);
}
return(viewModel);
}
if (throwOnError)
{
throw ExceptionManager.ViewModelCannotBeRestored();
}
}
catch (Exception e) when(!throwOnError)
{
Tracer.Warn(e.Flatten(true));
}
return(null);
}
private static CachedViewModel GetOrAddCachedViewModel(Guid id)
{
lock (CachedViewModels)
{
CachedViewModel value;
if (!CachedViewModels.TryGetValue(id, out value))
{
value = new CachedViewModel();
CachedViewModels[id] = value;
}
return value;
}
}