/// <summary>
/// Callback on visiting each node in the descendency
/// during an inheritable property change
/// </summary>
private static bool OnInheritablePropertyChanged(
DependencyObject d,
InheritablePropertyChangeInfo info,
bool visitedViaVisualTree)
{
Debug.Assert(d != null, "Must have non-null current node");
DependencyProperty dp = info.Property;
bool inheritanceNode = IsInheritanceNode(d, dp);
if (inheritanceNode)
{
BaseValueSourceInternal oldValueSource = BaseValueSourceInternal.Default;
INTERNAL_PropertyStorage storage;
if (INTERNAL_PropertyStore.TryGetInheritedPropertyStorage(d, dp, false, out storage))
{
oldValueSource = storage.BaseValueSourceInternal;
}
// If the oldValueSource is of lower precedence than Inheritance
// only then do we need to Invalidate the property
if (BaseValueSourceInternal.Inherited >= oldValueSource)
{
if (visitedViaVisualTree && typeof(FrameworkElement).IsInstanceOfType(d))
{
DependencyObject logicalParent = ((FrameworkElement)d).Parent;
if (logicalParent != null)
{
DependencyObject visualParent = VisualTreeHelper.GetParent(d);
if (visualParent != null && visualParent != logicalParent)
{
return(false);
}
}
}
return(d.SetInheritedValue(dp, info.NewValue, false));
}
else
{
if (storage == null)
{
// get the storage if we didn't to it ealier.
INTERNAL_PropertyStore.TryGetInheritedPropertyStorage(d, dp, true, out storage);
}
// set the inherited value so that it is known if at some point,
// the value of higher precedence that is currently used is removed.
// we know that the value of the property is not changing, so we can
// skip the call to UpdateEffectiveValue(...)
storage.InheritedValue = info.NewValue;
return(false);
}
}
return(false);
}
/// <summary>
/// Sets the inherited value of a dependency property on a DependencyObject. Do not use this method.
/// </summary>
/// <param name="dp">The identifier of the dependency property to set.</param>
/// <param name="value">The new local value.</param>
/// <param name="recursively">Specifies if the inherited value must be applied to the children of this DependencyObject.</param>
internal void SetInheritedValue(DependencyProperty dp, object value, bool recursively)
{
//-----------------------
// CALL "SET INHERITED VALUE" ON THE STORAGE:
//-----------------------
INTERNAL_PropertyStorage storage;
INTERNAL_PropertyStore.TryGetInheritedPropertyStorage(this, dp, true /*create*/, out storage);
INTERNAL_PropertyStore.SetInheritedValue(storage, value, recursively);
}