/// <summary>
/// An Animatable will return false from this method if there are any Clocks
/// animating any of its properties. If the Animatable has persistent animations
/// specified, but all of the Clocks have been removed, it may still return
/// true from this method if the Timelines themselves can be frozen.
/// </summary>
/// <param name="isChecking">
/// True if the Freezable should actually Freeze itself; false if
/// the Freezable should simply return whether it can be frozen.</param>
/// <returns>True if this object can be frozen; otherwise false.</returns>
protected override bool FreezeCore(bool isChecking)
{
if (IAnimatable_HasAnimatedProperties)
{
if (TraceFreezable.IsEnabled)
{
TraceFreezable.Trace(
TraceEventType.Warning,
TraceFreezable.UnableToFreezeAnimatedProperties,
this);
}
return(false);
}
return(base.FreezeCore(isChecking));
}
private static bool DefaultFreezeValueCallback(
DependencyObject d,
DependencyProperty dp,
EntryIndex entryIndex,
PropertyMetadata metadata,
bool isChecking)
{
// The expression check only needs to be done when isChecking is true
// because if we return false here the Freeze() call will fail.
if (isChecking)
{
if (d.HasExpression(entryIndex, dp))
{
if (TraceFreezable.IsEnabled)
{
TraceFreezable.Trace(
TraceEventType.Warning,
TraceFreezable.UnableToFreezeExpression,
d,
dp,
dp.OwnerType);
}
return(false);
}
}
if (!dp.IsValueType)
{
object value =
d.GetValueEntry(
entryIndex,
dp,
metadata,
RequestFlags.FullyResolved).Value;
if (value != null)
{
Freezable valueAsFreezable = value as Freezable;
if (valueAsFreezable != null)
{
if (!valueAsFreezable.Freeze(isChecking))
{
if (TraceFreezable.IsEnabled)
{
TraceFreezable.Trace(
TraceEventType.Warning,
TraceFreezable.UnableToFreezeFreezableSubProperty,
d,
dp,
dp.OwnerType);
}
return(false);
}
}
else // not a Freezable
{
DispatcherObject valueAsDispatcherObject = value as DispatcherObject;
if (valueAsDispatcherObject != null)
{
if (valueAsDispatcherObject.Dispatcher == null)
{
// The property is a free-threaded DispatcherObject; since it's
// already free-threaded it doesn't prevent this Freezable from
// becoming free-threaded too.
// It is up to the creator of this type to ensure that the
// DispatcherObject is actually immutable
}
else
{
// The value of this property derives from DispatcherObject and
// has thread affinity; return false.
if (TraceFreezable.IsEnabled)
{
TraceFreezable.Trace(
TraceEventType.Warning,
TraceFreezable.UnableToFreezeDispatcherObjectWithThreadAffinity,
d,
dp,
dp.OwnerType,
valueAsDispatcherObject);
}
return(false);
}
}
// The property isn't a DispatcherObject. It may be immutable (such as a string)
// or the user may have made it thread-safe. It's up to the creator of the type to
// do the right thing; we return true as an extensibility point.
}
}
}
return(true);
}