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;
}
/// <summary>
/// Does the lookup for our binding source data. This includes evaluation of our source
/// properties and the lookup for the data context.
/// </summary>
/// <remarks>
/// During the lookup, change handlers will be attached to all relevant properties
/// on the search path to the binding source. If one of the properties changes,
/// this binding will re-evaluate.
/// </remarks>
/// <param name="result">Resulting source descriptor, if it could be resolved.</param>
/// <returns><c>true</c>, if the binding source could be found and evaluated,
/// <c>false</c> if it could not be resolved (yet).</returns>
protected bool GetSourceDataDescriptor(out IDataDescriptor result)
{
ResetChangeHandlerAttachments();
result = null;
try
{
switch (_typeOfSource)
{
case SourceType.DataContext:
return(FindDataContext(out result));
case SourceType.SourceProperty:
#if DEBUG_BINDINGS
if (Source == null)
{
DebugOutput("GetSourceDataDescriptor doesn't have a Source", Source);
}
#endif
result = new DependencyPropertyDataDescriptor(this, "Source", _sourceProperty);
return(true);
case SourceType.RelativeSource:
DependencyObject current = _contextObject;
if (current == null)
{
return(false);
}
switch (RelativeSource.Mode)
{
case RelativeSourceMode.Self:
result = new ValueDataDescriptor(current);
return(true);
case RelativeSourceMode.TemplatedParent:
while (current != null)
{
DependencyObject last = current;
FindParent(last, out current, FindParentMode.HybridPreferVisualTree);
UIElement lastUIElement = last as UIElement;
if (lastUIElement != null)
{
AttachToSourcePathProperty(lastUIElement.TemplateNameScopeProperty);
if (lastUIElement.IsTemplateControlRoot)
{
result = new ValueDataDescriptor(current);
return(true);
}
}
}
#if DEBUG_BINDINGS
DebugOutput("GetSourceDataDescriptor didn't find TemplateParent");
#endif
return(false);
case RelativeSourceMode.FindAncestor:
if (FindAncestor(current, out current, FindParentMode.HybridPreferVisualTree,
RelativeSource.AncestorLevel, RelativeSource.AncestorType))
{
result = new ValueDataDescriptor(current);
return(true);
}
return(false);
//case RelativeSourceMode.PreviousData:
// // TODO: implement this
// throw new NotImplementedException(RelativeSourceMode.PreviousData.ToString());
default:
// Should never occur. If so, we have forgotten to handle a RelativeSourceMode
throw new NotImplementedException(
string.Format("RelativeSourceMode '{0}' is not implemented", RelativeSource.Mode));
}
case SourceType.ElementName:
INameScope nameScope;
if (!FindNameScope(out nameScope))
{
return(false);
}
object obj = nameScope.FindName(ElementName) as UIElement;
if (obj == null)
{
#if DEBUG_BINDINGS
DebugOutput("GetSourceDataDescriptor didn't find object with name '{0}'", ElementName);
#endif
return(false);
}
result = new ValueDataDescriptor(obj);
return(true);
default:
// Should never occur. If so, we have forgotten to handle a SourceType
throw new NotImplementedException(
string.Format("SourceType '{0}' is not implemented", _typeOfSource));
}
}
finally
{
AttachToSource(result);
IObservable observable = result == null ? null : result.Value as IObservable;
if (observable != null)
{
AttachToSourceObservable(observable);
}
}
}