private IWhere <T> MakeLink(Action <WhereImpl <T> > func)
{
//构造新链，传递给下一个
WhereImpl <T> sel = new WhereImpl <T>(this);
func.Invoke(sel);
return(sel);
}
/// <summary>
/// 条件
/// </summary>
/// <param name="_obj">继承类</param>
private WhereImpl(WhereImpl <T> _obj) : base(_obj._link_list)
{
this._where_que = new Queue <WherePair>(_obj._where_que);
if (this._link_list.FirstOrDefault(f => f is IWhere <T>) is IWhere <T> obj)
{
this._link_list.Remove(obj);
}
this._link_list.Add(this);
}