NHibernate查询计数

Question

我是NHibernate的新手，我想从数据库中获得一些行数。下面是我的代码，

SearchTemplate template = new SearchTemplate(); 
      template.Criteria = DetachedCriteria.For(typeof(hotel)); 
      template.Criteria.Add(Restrictions.Lt("CheckOutDate", SelDate) || Restrictions.Eq("CheckOutDate", SelDate)); 
      template.Criteria.Add(Restrictions.Eq("Canceled", "False")); 
    int count = template.Criteria.SetProjection(Projections.Count("ID")); 

它给了我一个错误，当我尝试编译应用程序，说 “无法隐式转换类型‘NHibernate.Criterion.DetachedCriteria’到‘廉政’”

我想有表酒店的行数..

Answer 1

你想用GetExecutableCriteria：

SearchTemplate template = new SearchTemplate(); 
     template.Criteria = DetachedCriteria.For(typeof(hotel)); 
     template.Criteria.Add(Restrictions.Lt("CheckOutDate", SelDate) || Restrictions.Eq("CheckOutDate", SelDate)); 
     template.Criteria.Add(Restrictions.Eq("Canceled", "False")); 

var count = DoCount(template.Criteria, session /* your session */); 

public long DoCount(DetachedCriteria criteria, ISession session) 
{ 
    return Convert.ToInt64(criteria.GetExecutableCriteria(session) 
        .SetProjection(Projections.RowCountInt64()) 
        .UniqueResult()); 
} 

在一个侧面说明，你应该看一看在使用NHibernate.Linq：

var result = (from h in Session.Linq<Hotel>() 
      where h.CheckOutDate <= SelDate 
      where h.Canceled != true 
      select h).Count(); 

更多信息here。