void SetDataContextSource(FrameworkElement fe)
{
if (DataContextSource != null)
{
DataContextSource.RemovePropertyChangedHandler(FrameworkElement.DataContextProperty, DataContextChanged);
}
DataContextSource = fe;
if (DataContextSource != null)
{
DataContextSource.AddPropertyChangedHandler(FrameworkElement.DataContextProperty, DataContextChanged);
}
// If a FrameworkElement binds to its own datacontext and the VisualParent is null, we end
// up here with a null DataContextSource. In this scenario we do not want to update.
if (DataContextSource != null || IsMentorDataContextBound)
{
PropertyPathWalker.Update(DataContextSource == null ? null : DataContextSource.DataContext);
}
}