/// <summary>
/// Suspends the change notifications until the returned <see cref="IDisposable"/> is disposed.
/// <example>
/// <code>
/// <![CDATA[
/// var fastCollection = new FastObservableCollection<int>();
/// using (fastCollection.SuspendChangeNotificaftions())
/// {
/// // Adding or removing events inside here will not raise events
/// fastCollection.Add(1);
/// fastCollection.Add(2);
/// fastCollection.Add(3);
///
/// fastCollection.Remove(3);
/// fastCollection.Remove(2);
/// fastCollection.Remove(1);
/// }
/// ]]>
/// </code>
/// </example>
/// </summary>
/// <param name="mode">The suspension Mode.</param>
/// <returns>IDisposable.</returns>
public IDisposable SuspendChangeNotifications(SuspensionMode mode)
{
if (_suspensionContext == null)
{
// Create new context
_suspensionContext = new SuspensionContext <T>(mode);
}
else if (_suspensionContext != null && _suspensionContext.Mode != mode)
{
throw Log.ErrorAndCreateException <InvalidOperationException>("Cannot change mode during another active suspension.");
}
return(new DisposableToken <FastObservableCollection <T> >(
this,
x =>
{
x.Instance._suspensionContext.Count++;
},
x =>
{
x.Instance._suspensionContext.Count--;
if (x.Instance._suspensionContext.Count == 0)
{
if (x.Instance.IsDirty)
{
x.Instance.IsDirty = false;
x.Instance.NotifyChanges();
}
x.Instance._suspensionContext = null;
}
}, _suspensionContext));
}
/// <summary>
/// The create mixed event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateMixedEvents <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsNotNull(nameof(suspensionContext), suspensionContext);
Argument.IsValid(nameof(suspensionContext.Mode), suspensionContext.Mode, mode => mode == SuspensionMode.Mixed);
return(new List <NotifyRangedCollectionChangedEventArgs> {
new NotifyRangedCollectionChangedEventArgs(suspensionContext.ChangedItems, suspensionContext.ChangedItemIndices, suspensionContext.MixedActions)
});
}
/// <summary>
/// The create event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateEvents <T>(this SuspensionContext <T> suspensionContext)
{
// No suspension context is the same as None mode
var mode = suspensionContext?.Mode ?? SuspensionMode.None;
// Fast return for no items in not None modes
if (mode != SuspensionMode.None && suspensionContext?.ChangedItems.Count == 0)
{
return(ArrayShim.Empty <NotifyRangedCollectionChangedEventArgs>());
}
if (!SuspensionContext <T> .EventsGeneratorsRegistry.Value.TryGetValue(mode, out var createEvents))
{
// ReSharper disable once LocalizableElement
throw new ArgumentOutOfRangeException(nameof(mode), $"The suspension mode '{mode}' is unhandled.");
}
return(createEvents(suspensionContext));
}
/// <summary>
/// Creates the none event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateNoneEvents <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsValid(nameof(suspensionContext), suspensionContext, context => context is null || context.Mode == SuspensionMode.None);
return(new List <NotifyRangedCollectionChangedEventArgs> {
new NotifyRangedCollectionChangedEventArgs()
});
}
/// <summary>
/// Creates the bash event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <param name="suspensionMode">The suspension mode.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="IList{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
private static IList <NotifyRangedCollectionChangedEventArgs> CreateBashEvents <T>(this SuspensionContext <T> suspensionContext, SuspensionMode suspensionMode)
{
var i = 0;
var changedItems = new List <T>();
var changedItemIndices = new List <int>();
var previousAction = (NotifyCollectionChangedAction?)null;
var eventArgsList = new List <NotifyRangedCollectionChangedEventArgs>();
foreach (var action in suspensionContext.MixedActions)
{
// If action changed, create event args for remembered items
if (previousAction.HasValue && action != previousAction.Value)
{
// Create and add event args
eventArgsList.Add(new NotifyRangedCollectionChangedEventArgs(changedItems, changedItemIndices, suspensionMode, previousAction.Value));
// Reset lists
changedItems = new List <T>();
changedItemIndices = new List <int>();
}
// Remember item and index
changedItems.Add(suspensionContext.ChangedItems[i]);
changedItemIndices.Add(suspensionContext.ChangedItemIndices[i]);
// Update to current action
previousAction = action;
i++;
}
// Create event args for last item(s)
if (changedItems.Count != 0 && previousAction != null)
{
eventArgsList.Add(new NotifyRangedCollectionChangedEventArgs(changedItems, changedItemIndices, suspensionMode, previousAction.Value));
}
return(eventArgsList);
}
/// <summary>
/// The is mixed mode.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns><c>True</c> if <see cref="SuspensionMode"/> is one of the mixed modes; otherwise, <c>false</c>.</returns>
public static bool IsMixedMode <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsNotNull(nameof(suspensionContext), suspensionContext);
return(suspensionContext.Mode.IsMixedMode());
}
/// <summary>
/// Creates the silent event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateSilentEvents <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsNotNull(nameof(suspensionContext), suspensionContext);
Argument.IsValid(nameof(suspensionContext.Mode), suspensionContext.Mode, mode => mode == SuspensionMode.Silent);
return(ArrayShim.Empty <NotifyRangedCollectionChangedEventArgs>());
}
/// <summary>
/// The create mixed consolidate event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateMixedConsolidateEvents <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsNotNull(nameof(suspensionContext), suspensionContext);
Argument.IsValid(nameof(suspensionContext.Mode), suspensionContext.Mode, mode => mode == SuspensionMode.MixedConsolidate);
var events = suspensionContext.CreateBashEvents(suspensionContext.Mode);
bool restartRequired;
do
{
restartRequired = false;
for (var i = events.Count - 1; i >= 1; i--)
{
var currentEvent = events[i];
if (currentEvent.Indices.Count > 0)
{
var previousEvent = events[i - 1];
restartRequired = currentEvent.Action == previousEvent.Action ? previousEvent.ConsolidateItemsByAppend(currentEvent) : previousEvent.ConsolidateItems(currentEvent);
}
if (currentEvent.Indices.Count == 0)
{
events.RemoveAt(i);
restartRequired = i < events.Count;
}
}
}while (restartRequired);
return(events);
}
/// <summary>
/// The create mixed bash event args list.
/// </summary>
/// <param name="suspensionContext">The suspension context.</param>
/// <typeparam name="T">The type of collection item.</typeparam>
/// <returns>The <see cref="ICollection{NotifyRangedCollectionChangedEventArgs}"/>.</returns>
public static ICollection <NotifyRangedCollectionChangedEventArgs> CreateMixedBashEvents <T>(this SuspensionContext <T> suspensionContext)
{
Argument.IsNotNull(nameof(suspensionContext), suspensionContext);
Argument.IsValid(nameof(suspensionContext.Mode), suspensionContext.Mode, mode => mode == SuspensionMode.MixedBash);
return(suspensionContext.CreateBashEvents(SuspensionMode.MixedBash));
}
