private TaggedObservableValue <TResult, int> AttachItem(TSource item)
{
if (item != null)
{
TaggedObservableValue <TResult, int> lambdaResult;
if (!lambdas.TryGetValue(item, out lambdaResult))
{
lambdaResult = lambda.InvokeTagged <int>(item, 0);
lambdaResult.ValueChanged += LambdaChanged;
lambdas.Add(item, lambdaResult);
}
lambdaResult.Tag++;
return(lambdaResult);
}
else
{
if (nullLambda == null)
{
nullLambda = lambda.InvokeTagged(item, 0);
nullLambda.ValueChanged += LambdaChanged;
}
nullLambda.Tag++;
return(nullLambda);
}
}
private TaggedObservableValue <TResult, int> AttachItem(TSource item)
{
if (item != null)
{
TaggedObservableValue <TResult, int> lambdaResult;
if (!lambdaInstances.TryGetValue(item, out lambdaResult))
{
lambdaResult = lambda.InvokeTagged(item, 0);
lambdaResult.Successors.Set(this);
lambdaInstances.Add(item, lambdaResult);
}
lambdaResult.Tag++;
return(lambdaResult);
}
else
{
if (nullLambda == null)
{
nullLambda = lambda.InvokeTagged(item, 0);
nullLambda.Successors.Set(this);
}
nullLambda.Tag++;
return(nullLambda);
}
}
private void NotifySource(CollectionChangedNotificationResult <TSource> sourceChange, List <TResult> added, List <TResult> removed)
{
foreach (var item in sourceChange.AllRemovedItems)
{
if (item != null)
{
var lambdaResult = lambdaInstances[item];
lambdaResult.Tag--;
removed.Add(lambdaResult.Value);
if (lambdaResult.Tag == 0)
{
lambdaInstances.Remove(item);
lambdaResult.Successors.Unset(this);
}
}
else if (nullLambda != null)
{
nullLambda.Tag--;
if (nullLambda.Tag == 0)
{
nullLambda.Successors.Unset(this);
nullLambda = null;
}
}
}
foreach (var item in sourceChange.AllAddedItems)
{
var lambdaResult = AttachItem(item);
added.Add(lambdaResult.Value);
}
}
private void OnLambdaValueChanged(TaggedObservableValue <TResult, int> value, ValueChangedEventArgs e)
{
if (e == null)
{
throw new ArgumentNullException("e");
}
TResult result = (TResult)e.NewValue;
TResult oldResult = (TResult)e.OldValue;
for (int i = 0; i < value.Tag; i++)
{
OnUpdateItem(result, oldResult);
}
}
protected abstract void OnLambdaValueChanged(TaggedObservableValue <TLambdaResult, TResult> value, ValueChangedEventArgs e);
protected virtual void AttachItem(TSource sourceItem, TaggedObservableValue <TLambdaResult, TResult> lambdaValue)
{
}
protected abstract bool AddItem(TSource sourceItem, TaggedObservableValue <TLambdaResult, TResult> lambdaValue);
private void NotifySource(ICollectionChangedNotificationResult <TSource> sourceChange, List <TResult> added, List <TResult> removed, bool checkConflicts)
{
if (sourceChange.RemovedItems != null)
{
foreach (var item in sourceChange.RemovedItems)
{
if (item != null)
{
var lambdaResult = lambdaInstances[item];
lambdaResult.Tag--;
if (checkConflicts)
{
var addIndex = added.IndexOf(lambdaResult.Value);
if (addIndex != -1)
{
added.RemoveAt(addIndex);
}
else
{
removed.Add(lambdaResult.Value);
}
}
else
{
removed.Add(lambdaResult.Value);
}
if (lambdaResult.Tag == 0)
{
lambdaInstances.Remove(item);
lambdaResult.Successors.Unset(this);
}
}
else if (nullLambda != null)
{
nullLambda.Tag--;
if (nullLambda.Tag == 0)
{
nullLambda.Successors.Unset(this);
nullLambda = null;
}
}
}
}
if (sourceChange.AddedItems != null)
{
foreach (var item in sourceChange.AddedItems)
{
var lambdaResult = AttachItem(item);
if (checkConflicts)
{
var removeIndex = removed.IndexOf(lambdaResult.Value);
if (removeIndex != -1)
{
removed.RemoveAt(removeIndex);
}
else
{
added.Add(lambdaResult.Value);
}
}
else
{
added.Add(lambdaResult.Value);
}
}
}
}
private void SourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
if (e.Action == NotifyCollectionChangedAction.Move)
{
return;
}
if (e.Action != NotifyCollectionChangedAction.Reset)
{
if (e.OldItems != null)
{
var removed = new List <TResult>();
foreach (TSource item in e.OldItems)
{
if (item != null)
{
TaggedObservableValue <TResult, int> lambdaResult;
if (lambdas.TryGetValue(item, out lambdaResult))
{
lambdaResult.Tag--;
if (lambdaResult.Tag == 0)
{
lambdas.Remove(item);
lambdaResult.ValueChanged -= LambdaChanged;
lambdaResult.Detach();
}
removed.Add(lambdaResult.Value);
}
else
{
throw new InvalidOperationException();
}
}
else if (nullLambda != null)
{
nullLambda.Tag--;
if (nullLambda.Tag == 0)
{
nullLambda.ValueChanged -= LambdaChanged;
nullLambda.Detach();
nullLambda = null;
}
}
}
OnRemoveItems(removed, e.OldStartingIndex);
}
if (e.NewItems != null)
{
var added = new List <TResult>();
foreach (TSource item in e.NewItems)
{
var lambdaResult = AttachItem(item);
added.Add(lambdaResult.Value);
}
OnAddItems(added, e.NewStartingIndex);
}
}
else
{
DetachSource();
OnCleared();
}
}
