/// <summary>
/// This method must be used in derived objects next way: set { SetNotifyingProperty(() => PropertyName, ref fieldForPropertyName, value); }
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="expressionWithPropertyName"></param>
/// <param name="fieldForPropertyName"></param>
/// <param name="value"></param>
protected void SetNotifyingProperty <T>(Expression <Func <T> > expressionWithPropertyName, ref T fieldForPropertyName, T value)
{
if (!fieldForPropertyName.EqualsWithNullHandling(value))
{
T oldValue = fieldForPropertyName;
fieldForPropertyName = value;
string propertyName;
PropertyEventsPath currentPropertyEventsPath;
if (_propertiesEvents != null)
{
propertyName = expressionWithPropertyName.GetBodyMemberName();
if (_propertiesEvents.TryGetValue(propertyName, out currentPropertyEventsPath))
{
if (oldValue == null)
{
if (currentPropertyEventsPath.PropertiesEvents != null)
{
try
{
INotifyingObject newValNotifyingObj = (INotifyingObject)value;
newValNotifyingObj.SetPropertiesEvents(MergePropertyEventsPaths(newValNotifyingObj.GetPropertiesEvents(), currentPropertyEventsPath.PropertiesEvents));
}
catch (InvalidCastException ex)
{
throw new InvalidOperationException(string.Format("Early handlers were subscribed to child properties: \"{0}\" "
+ "but it's a violating operation because a parent property \"{1}\" doesn't implement \"{3}\"",
string.Join(", ", currentPropertyEventsPath.PropertiesEvents.Select(pair => string.Format("{0}: {1}", pair.Key, pair.Value)).ToArray()),
propertyName, typeof(INotifyingObject), ex));
}
currentPropertyEventsPath.PropertiesEvents = null;
if (currentPropertyEventsPath.Events == null)
{
_propertiesEvents.Remove(propertyName);
}
}
}
if (currentPropertyEventsPath.Events != null)
{
ChangedEventArgs <T> e = new ChangedEventArgs <T>(oldValue, value);
foreach (ChangedEventHandler <T> changedEventHandler in currentPropertyEventsPath.Events)
{
changedEventHandler(this, e);
}
return;
}
}
}
else
{
currentPropertyEventsPath = null;
propertyName = null;
}
INotifyingObject oldValNotifyingObj = oldValue as INotifyingObject;
if (oldValNotifyingObj != null)
{
oldValNotifyingObj.ChildrenChanged -= OnChildrenChanged;
}
if (value != null)
{
INotifyingObject newValNotifyingObj = value as INotifyingObject;
if (newValNotifyingObj != null)
{
newValNotifyingObj.ChildrenChanged += OnChildrenChanged;
}
}
else
{
var oldValNotifyingObjPropertiesEvents = oldValNotifyingObj.GetPropertiesEvents();
if (oldValNotifyingObjPropertiesEvents != null)
{
if (currentPropertyEventsPath == null)
{
currentPropertyEventsPath = new PropertyEventsPath {
PropertiesEvents = oldValNotifyingObjPropertiesEvents
};
if (propertyName == null)
{
propertyName = expressionWithPropertyName.GetBodyMemberName();
}
_propertiesEvents.Add(propertyName, currentPropertyEventsPath);
}
else
{
currentPropertyEventsPath.PropertiesEvents = MergePropertyEventsPaths(currentPropertyEventsPath.PropertiesEvents, oldValNotifyingObjPropertiesEvents);
}
}
}
OnChildrenChanged(this, null);
}
}
