/// <summary>Creates a new <see cref="TriggerSink"/> instance.</summary>
public TriggerSink(BplBindingTrigger trigger, BplPropertyPath path) {
Trigger = trigger;
Path = path;
}
// converts the given BPL property path to a WPF property path
private string _toBindingPathString(BplPropertyPath path) {
var parts = new string[path.Count];
for (var i = 0; i < path.Count; i++) {
var segment = path[i];
var period = (i < path.Count - 1 ? "." : "");
if (segment.IsA<BplPropertyPath.SingleItemSegment>()) {
parts[i] = segment.Name + period;
} else if (segment.IsA<BplPropertyPath.IndexedItemSegment>()) {
var index = ((BplPropertyPath.IndexedItemSegment)segment).Index;
parts[i] = segment.Name + "[" + index + "]" + period;
} else if (segment.IsA<BplPropertyPath.CurrentItemSegment>()) {
parts[i] = segment.Name + "/";
} else if (segment.IsA<BplPropertyPath.CollectionSegment>()) {
parts[i] = segment.Name + ".LastChange";
}
}
return parts.Join("");
}
// Gets the value at the given property path segment
private object _getSegmentValue(BplObject source, BplPropertyPath.PathSegment segment) {
if (source != null) {
var property = source.Class.GetProperty(segment.Name);
if (property != null) {
var value = property.GetValue(source);
if (segment.IsA<BplPropertyPath.SingleItemSegment>()) {
return value;
} else {
var collection = value as IBplCollection;
if (collection != null) {
if (segment.IsA<BplPropertyPath.CollectionSegment>()) {
return collection;
} else if (segment.IsA<BplPropertyPath.IndexedItemSegment>()) {
var index = ((BplPropertyPath.IndexedItemSegment)segment).Index;
if (index >= 0 && index < collection.Count) {
return collection[index];
}
} else if (segment.IsA<BplPropertyPath.CurrentItemSegment>()) {
var collectionView = CollectionViewSource.GetDefaultView(collection);
if (collectionView != null) {
return collectionView.CurrentItem;
}
}
}
}
}
}
return DependencyProperty.UnsetValue;
}
// Gets the value at the end of the given property path
private object _getPathValue(BplObject source, BplPropertyPath path) {
var lastSource = _getLastSource(source, path);
if (lastSource != null) {
var value = _getSegmentValue(lastSource, path.LastSegment);
if (value != DependencyProperty.UnsetValue) return value;
}
return null;
}
// Traverses the path and returns the most immediate source (the last object on the path before the actual property value)
private BplObject _getLastSource(BplObject source, BplPropertyPath path) {
if (source == null || path.Count == 0) return null;
for (var i = 0; i < path.Count - 1; i++) {
source = _getSegmentValue(source, path[i]) as BplObject;
if (source == null) break;
}
return source;
}
// Gets the BPL change data that corresponds to the given property path and change event
private BplChange _getChangeData(BplObject source, BplPropertyPath path, DependencyPropertyChangedEventArgs e) {
if (e.NewValue.IsA<BplCollectionChange>()) {
return (BplChange)e.NewValue;
} else {
var lastSource = _getLastSource(source, path);
if (lastSource != null) {
var lastProperty = lastSource.Class.GetProperty(path.LastSegment.Name);
if (lastProperty != null && !lastProperty.IsCollection && !lastProperty.IsCalculated) {
return new BplPropertyChange(lastSource, lastProperty, e.OldValue, e.NewValue);
}
}
return null;
}
}
