protected virtual void OnPropertyChanging(string propertyName)
{
PropertyChangingEventHandler propertyChanging = PropertyChanging;
if (propertyChanging == null)
{
return;
}
DispatcherHelper.BeginInvokeIfRequired(
() => propertyChanging.Invoke(this, new PropertyChangingEventArgs(propertyName)),
DispatcherPriority.DataBind
);
}