/// <summary>集合相减</summary>
/// <param name="entities1">第一个实体集合</param>
/// <param name="entities2">第二个实体集合</param>
/// <returns></returns>
public static EntityList <T> operator -(EntityList <T> entities1, EntityList <T> entities2)
{
if ((entities1 == null || entities1.Count < 1) &&
(entities2 == null || entities2.Count < 1))
{
return(entities1);
}
var list = new EntityList <T>(entities1);
list.RemoveAll(e => entities2.Contains(e));
return(list);
}
