public virtual bool TryCreatePreview(ref PreviewEntity ent, string model)
{
if (!ent.IsValid())
{
ent = new PreviewEntity();
ent.SetModel(model);
}
if (Previews == null)
{
Previews = new List <PreviewEntity>();
}
if (!Previews.Contains(ent))
{
Previews.Add(ent);
}
return(ent.IsValid());
}