protected IDataDescriptor GetDataDescriptor(UIElement element)
{
string targetName = Storyboard.GetTargetName(this);
object targetObject = null;
if (targetName == null)
targetObject = element;
else
{
INameScope ns = element.FindNameScope();
if (ns != null)
targetObject = ns.FindName(targetName);
if (targetObject == null)
targetObject = element.FindElement(new NameMatcher(targetName));
if (targetObject == null)
return null;
}
try
{
IDataDescriptor result = new ValueDataDescriptor(targetObject);
if (_propertyExpression != null && _propertyExpression.Evaluate(result, out result))
return result;
}
catch (XamlBindingException e)
{
ServiceRegistration.Get<ILogger>().Warn("PropertyAnimationTimeline: Error evaluating expression '{0}' on target object '{1}'", e, _propertyExpression, targetObject);
}
return null;
}
public T GetElement(object source)
{
IDataDescriptor result;
_compiledPath.Evaluate(new ValueDataDescriptor(source), out result);
if (result == null)
{
return(null);
}
return((T)TypeConverter.Convert(result.Value, typeof(T)));
}
/// <summary>
/// Will be called to evaluate our source value based on all available
/// property and context states.
/// This method will also be automatically re-called when any object involved in the
/// evaluation process of our source value was changed.
/// </summary>
/// <returns><c>true</c>, if the source value based on all input data
/// could be evaluated, else <c>false</c>.</returns>
protected virtual bool UpdateSourceValue()
{
bool sourceValueValid = false;
try
{
IDataDescriptor evaluatedValue;
if (!GetSourceDataDescriptor(out evaluatedValue))
{
// Do nothing if not all necessary properties can be resolved at the current time
return(false);
}
if (_compiledPath != null)
{
try
{
if (!_compiledPath.Evaluate(evaluatedValue, out evaluatedValue))
{
return(false);
}
}
catch (XamlBindingException)
{
return(false);
}
}
// If no path is specified, evaluatedValue will be the source value
IsSourceValueValid = sourceValueValid = true;
_evaluatedSourceValue.SourceValue = evaluatedValue;
return(true);
}
finally
{
IsSourceValueValid = sourceValueValid;
}
}
