private async Task SaveChanges(bool showToast)
{
await _repository
.SaveAsync(_trackingCollection.GetChanges(), DisposeCancellationToken)
.WithBusyIndicator(this, UiResources.SaveBusyMessage);
_trackingCollection.SetStateForAll(entity => entity.State.IsDeleted(), EntityState.Detached);
_trackingCollection.SetStateForAll(entity => !entity.State.IsDeleted(), EntityState.Unchanged);
this.OnPropertyChanged(() => v => v.HasChanges);
if (showToast)
{
_toastPresenter.ShowAsync(UiResources.SaveToastMessage, ToastDuration.Long);
}
}
/// <summary>
/// Restore items marked as deleted.
/// </summary>
/// <param name="changeTracker">Change-tracking collection</param>
/// <param name="visitationHelper">Circular reference checking helper</param>
public static void RestoreDeletes(this ITrackingCollection changeTracker, ObjectVisitationHelper visitationHelper = null)
{
ObjectVisitationHelper.EnsureCreated(ref visitationHelper);
// Get cached deletes
var removedDeletes = changeTracker.GetChanges(true).Cast <ITrackable>().ToList();
// Restore deleted items
if (removedDeletes.Any())
{
var isTracking = changeTracker.Tracking;
changeTracker.Tracking = false;
foreach (var delete in removedDeletes)
{
var items = changeTracker as IList;
if (items != null && !items.Contains(delete))
{
items.Add(delete);
}
}
changeTracker.Tracking = isTracking;
}
foreach (var item in changeTracker.Cast <ITrackable>())
{
// Prevent endless recursion
if (!visitationHelper.TryVisit(item))
{
continue;
}
// Iterate entity properties
foreach (var navProp in item.GetNavigationProperties())
{
// Process 1-1 and M-1 properties
foreach (var refProp in navProp.AsReferenceProperty())
{
// Get changed ref prop
ITrackingCollection refChangeTracker = item.GetRefPropertyChangeTracker(refProp.Property.Name);
// Restore deletes on rep prop
if (refChangeTracker != null)
{
refChangeTracker.RestoreDeletes(visitationHelper);
}
}
// Process 1-M and M-M properties
foreach (var colProp in navProp.AsCollectionProperty <ITrackingCollection>())
{
colProp.EntityCollection.RestoreDeletes(visitationHelper);
}
}
}
}
public async void LoadState(IDataContext state)
{
ITrackingCollection trackingCollection = state.GetData(StateConstant);
if (trackingCollection == null)
{
return;
}
IList <IEntityStateEntry> changes = trackingCollection.GetChanges();
await _initializedTask;
_trackingCollection.UpdateStates(changes);
foreach (IEntityStateEntry change in changes)
{
var oldItem = (ProductModel)change.Entity;
ProductModel currentItem = GridViewModel.OriginalItemsSource.FirstOrDefault(model => model.Id == oldItem.Id);
switch (change.State)
{
case EntityState.Added:
GridViewModel.OriginalItemsSource.Add(oldItem);
break;
case EntityState.Modified:
if (currentItem != null)
{
GridViewModel.OriginalItemsSource.Remove(currentItem);
}
GridViewModel.OriginalItemsSource.Add(oldItem);
break;
case EntityState.Deleted:
if (currentItem != null)
{
GridViewModel.OriginalItemsSource.Remove(currentItem);
}
break;
}
}
this.OnPropertyChanged(() => v => v.HasChanges);
}
/// <summary>
/// Recursively remove items marked as deleted.
/// </summary>
/// <param name="changeTracker">Change-tracking collection</param>
/// <param name="visitationHelper">Circular reference checking helper</param>
public static void RemoveRestoredDeletes(this ITrackingCollection changeTracker, ObjectVisitationHelper visitationHelper = null)
{
ObjectVisitationHelper.EnsureCreated(ref visitationHelper);
// Iterate items in change-tracking collection
var items = changeTracker as IList;
if (items == null)
{
return;
}
var count = items.Count;
for (int i = count - 1; i > -1; i--)
{
// Get trackable item
var item = items[i] as ITrackable;
if (item == null)
{
continue;
}
// Prevent endless recursion
if (!visitationHelper.TryVisit(item))
{
continue;
}
// Iterate entity properties
foreach (var navProp in item.GetNavigationProperties())
{
// Process 1-1 and M-1 properties
foreach (var refProp in navProp.AsReferenceProperty())
{
// Get changed ref prop
ITrackingCollection refChangeTracker = item.GetRefPropertyChangeTracker(refProp.Property.Name);
// Remove deletes on rep prop
if (refChangeTracker != null)
{
refChangeTracker.RemoveRestoredDeletes(visitationHelper);
}
}
// Process 1-M and M-M properties
foreach (var colProp in navProp.AsCollectionProperty <ITrackingCollection>())
{
colProp.EntityCollection.RemoveRestoredDeletes(visitationHelper);
}
}
// Remove item if marked as deleted
var removedDeletes = changeTracker.GetChanges(true).Cast <ITrackable>().ToList();
if (item.TrackingState == TrackingState.Deleted)
{
var isTracking = changeTracker.Tracking;
changeTracker.Tracking = false;
if (removedDeletes.Contains(item))
{
items.Remove(item);
}
changeTracker.Tracking = isTracking;
}
}
}