private void Cleanup()
{
if (_weakEventListener != null)
{
_weakEventListener.Detach();
}
_weakEventListener = null;
}
protected virtual void OnColumnsChanged(DependencyPropertyChangedEventArgs e)
{
var oldColumns = e.OldValue as INotifyCollectionChanged;
var newColumns = e.NewValue as INotifyCollectionChanged;
if (oldColumns != null && _weakEventListener != null)
{
_weakEventListener.Detach();
_weakEventListener = null;
}
if (newColumns != null)
{
_weakEventListener = new WeakEventListener <DataGridDynamicColumnsBehavior, object, NotifyCollectionChangedEventArgs>(this);
_weakEventListener.OnEventAction = (instance, source, eventArgs) => instance.OnColumnsCollectionChanged(source, eventArgs);
_weakEventListener.OnDetachAction = (weakEventListener) => newColumns.CollectionChanged -= weakEventListener.OnEvent;
newColumns.CollectionChanged += _weakEventListener.OnEvent;
}
UpdateColumns();
}