// returns the AProperty value for the passed object.
public PropertyType GetProperty(ObjectType obj)
{
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper =
GetValueWrapper(obj);
return(GetCurrentValueFromWrapper(valueWrapper));
}
PropertyType GetCurrentValueFromWrapper(APropertyValueWrapper <ObjectType, PropertyType> valueWrapper)
{
if (valueWrapper == null)
{
return(_defaultValue);
}
return(valueWrapper.APropertyValue);
}
// removes the individual change handler
// from a passed object.
public void RemoveOnPropertyChangedHandler
(
ObjectType obj,
OnPropertyChangedDelegate <ObjectType, PropertyType> propChangedHandler
)
{
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper =
GetValueWrapper(obj, true);
valueWrapper.OnPropertyChangedEvent -= propChangedHandler;
}
// if shouldRemove flag is true, newPropertyValue should be default
void SetOrRemoveProperty(ObjectType obj, PropertyType newPropertyValue, bool shouldRemove = false)
{
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper =
GetValueWrapper(obj);
PropertyType oldPropertyValue = GetCurrentValueFromWrapper(valueWrapper);
if (oldPropertyValue.ObjEquals(newPropertyValue))
{
// do not do or any event firing if the property did not change
// this is important to prevent circlular updates
// in case of the bindings.
return;
}
// check the global BeforePropertyChanged Event
if (BeforePropertyChangedFn != null)
{
// if returned false, do not proceed
if (!BeforePropertyChangedFn(obj, oldPropertyValue, newPropertyValue))
{
return;
}
}
if (!shouldRemove)
{
if (valueWrapper == null)
{
valueWrapper = new APropertyValueWrapper <ObjectType, PropertyType>
{
Obj = obj
};
_objectToPropValueMap.Add(obj, valueWrapper);
}
valueWrapper.APropertyValue = newPropertyValue;
}
else
{
_objectToPropValueMap.Remove(obj);
}
valueWrapper.FireOnPropertyChangedEvent(oldPropertyValue);
if (shouldRemove)
{
valueWrapper.ClearOnPropertyChangedEvent();
}
OnPropertyChangedFn?.Invoke(obj, oldPropertyValue, newPropertyValue);
}
// clears AProperty from the passed object.
public void ClearAProperty(ObjectType obj)
{
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper =
GetValueWrapper(obj);
if (valueWrapper == null)
{
return;
}
SetOrRemoveProperty(obj, _defaultValue, true);
//_objectToPropValueMap.Remove(obj);
}
// adds an individual property change handler
// on the passed object. (other object won't get affected)
public void AddOnPropertyChangedHandler
(
ObjectType obj,
OnPropertyChangedDelegate <ObjectType, PropertyType> propChangedHandler
)
{
if (propChangedHandler == null)
{
return;
}
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper =
GetValueWrapper(obj, true);
valueWrapper.OnPropertyChangedEvent += propChangedHandler;
}
// given an object returns the ValueWrapper corresponding to the AProperty value
// of this object. If it is null and createIfDoesNotExist flag set to true,
// it will create the ValueWrapper with default value.
APropertyValueWrapper <ObjectType, PropertyType> GetValueWrapper(ObjectType obj, bool createIfDoesNotExist = false)
{
APropertyValueWrapper <ObjectType, PropertyType> valueWrapper = null;
if (!_objectToPropValueMap.TryGetValue(obj, out valueWrapper))
{
if (createIfDoesNotExist)
{
if (valueWrapper == null)
{
valueWrapper = new APropertyValueWrapper <ObjectType, PropertyType>
{
Obj = obj,
APropertyValue = _defaultValue
};
_objectToPropValueMap.Add(obj, valueWrapper);
}
}
}
return(valueWrapper);
}
