/// <summary>
/// Converts the given <paramref name="observableListChange" /> to its <see cref="ListChangedEventArgs" /> counter part.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="observableListChange">The <see cref="IObservableListChange{T}" /> instance containing the event data.</param>
/// <returns></returns>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.ArgumentOutOfRangeException"></exception>
public static ListChangedEventArgs ToListChangedEventArgs <T>(this IObservableListChange <T> observableListChange)
{
if (observableListChange == null)
{
throw new ArgumentNullException(nameof(observableListChange));
}
switch (observableListChange.ChangeType)
{
case ObservableListChangeType.ItemAdded:
return(new ListChangedEventArgs(ListChangedType.ItemAdded, observableListChange.Index));
case ObservableListChangeType.ItemChanged:
return(new ListChangedEventArgs(ListChangedType.ItemChanged, observableListChange.Index, observableListChange.OldIndex));
case ObservableListChangeType.ItemMoved:
return(new ListChangedEventArgs(ListChangedType.ItemMoved, observableListChange.Index, observableListChange.OldIndex));
case ObservableListChangeType.ItemRemoved:
return(new ListChangedEventArgs(ListChangedType.ItemDeleted, observableListChange.Index, observableListChange.OldIndex));
case ObservableListChangeType.Reset:
return(new ListChangedEventArgs(ListChangedType.Reset, observableListChange.Index));
default:
throw new ArgumentOutOfRangeException(nameof(observableListChange),
$"Only {ObservableListChangeType.ItemAdded}, {ObservableListChangeType.ItemChanged}, {ObservableListChangeType.ItemMoved}, {ObservableListChangeType.ItemRemoved} and {ObservableListChangeType.Reset} are supported.");
}
}
/// <summary>
/// Initializes a new instance of the <see cref="ObservableListChangedEventArgs{T}"/> class.
/// </summary>
/// <param name="observableListChange">The observable list change.</param>
/// <exception cref="System.ArgumentNullException"></exception>
public ObservableListChangedEventArgs(IObservableListChange <T> observableListChange)
{
if (observableListChange == null)
{
throw new ArgumentNullException(nameof(observableListChange));
}
Change = observableListChange;
}
/// <summary>
/// Converts the given <paramref name="observableListChange" /> to its <see cref="NotifyCollectionChangedEventArgs" /> counter part.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="observableListChange">The <see cref="IObservableListChange{T}" /> instance containing the event data.</param>
/// <returns></returns>
/// <exception cref="System.ArgumentNullException"></exception>
/// <exception cref="System.ArgumentOutOfRangeException"></exception>
public static NotifyCollectionChangedEventArgs ToNotifyCollectionChangedEventArgs <T>(this IObservableListChange <T> observableListChange)
{
if (observableListChange == null)
{
throw new ArgumentNullException(nameof(observableListChange));
}
switch (observableListChange.ChangeType)
{
case ObservableListChangeType.ItemAdded:
return(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Add, observableListChange.Item, observableListChange.Index));
case ObservableListChangeType.ItemChanged:
return(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Replace, observableListChange.Item, observableListChange.Index));
case ObservableListChangeType.ItemMoved:
return(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Move, observableListChange.Item, observableListChange.Index, observableListChange.OldIndex));
case ObservableListChangeType.ItemRemoved:
return(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Remove, observableListChange.Item, observableListChange.Index, observableListChange.OldIndex));
case ObservableListChangeType.Reset:
return(new NotifyCollectionChangedEventArgs(NotifyCollectionChangedAction.Reset));
default:
throw new ArgumentOutOfRangeException(nameof(observableListChange),
$"Only {ObservableListChangeType.ItemAdded}, {ObservableListChangeType.ItemChanged}, {ObservableListChangeType.ItemMoved}, {ObservableListChangeType.ItemRemoved} and {ObservableListChangeType.Reset} are supported.");
}
}
/// <summary>
/// Notifies all <see cref="ListChanges" /> and <see cref="INotifyObservableResets.Resets" /> subscribers and
/// raises the (observable)collection changed events.
/// </summary>
/// <param name="observableListChange">The observable list change.</param>
protected virtual void NotifySubscribersAboutListChanges(IObservableListChange <T> observableListChange)
{
// This is similar to what ObservableCollection implements via its NotifyObserversAboutCollectionChanges method,
// however:
// - no need to handle count-relevant changes because the underlying ObservableCollection takes care of this
// - no (extra) (Raise)CollectionChanged call here, again.. already done by the ObservableCollection
// - however as 'Move's are only possible for / with ObservableLists, we also raise a PropertyChangedEvent for 'Item[]' (for wpf) in case of a item move(s)
if (observableListChange == null)
{
throw new ArgumentNullException(nameof(observableListChange));
}
CheckForAndThrowIfDisposed();
// go ahead and check whether a Reset or item add, -change, -move or -remove shall be signaled
// .. based on the ThresholdAmountWhenChangesAreNotifiedAsReset value
var actualObservableListChange =
(observableListChange.ChangeType == ObservableListChangeType.Reset ||
IsItemsChangedAmountGreaterThanResetThreshold(1, ThresholdAmountWhenChangesAreNotifiedAsReset))
? ObservableListChange <T> .Reset(this)
: observableListChange;
// raise events and notify about list changes
try
{
ListChangesObserver.OnNext(actualObservableListChange);
}
catch (Exception exception)
{
var observerException = new ObserverException(
$"An error occured notifying {nameof(ListChanges)} observers of this {this.GetType().Name}.",
exception);
ObserverExceptionsObserver.OnNext(observerException);
if (observerException.Handled == false)
{
throw;
}
}
if (actualObservableListChange.ChangeType == ObservableListChangeType.ItemMoved)
{
try
{
RaisePropertyChanged(ItemIndexerName);
}
catch (Exception exception)
{
var observerException = new ObserverException(
$"An error occured notifying {nameof(PropertyChanged)} subscribers of this {this.GetType().Name}.",
exception);
ObserverExceptionsObserver.OnNext(observerException);
if (observerException.Handled == false)
{
throw;
}
}
}
}
