Nhibernate 2.0 Efficient DataList Control and ObjectDataSource

Question

How do I do what Scott did in one call using nHibernate 2 ObjectDataSource

http://weblogs.asp.net/scottgu/archive/2006/01/07/434787.aspx

below is my data access method

public IList GetListOfUser(int rows, int pageIndex) { IList userList = null; using (ITransaction tx = _session.BeginTransaction()) { try { userList = _session.CreateQuery("Select u from User u where u.DateSubmitted is not null") .SetFirstResult(rows * (pageIndex - 1) + 1) .SetMaxResults(rows) .List(); tx.Commit(); } catch (NHibernate.HibernateException ex) { tx.Rollback(); AppUtil.LogHelper.WriteLog(LogLevel.ERROR, ex.ToString()); throw; } } return userList; } 

Answer 1

In fact, you can get the results page and the total number of records in one server call using this helper method if you use ICriteria queries:

  protected IList<T> GetByCriteria( ICriteria criteria, int pageIndex, int pageSize, out long totalCount) { ICriteria recordsCriteria = CriteriaTransformer.Clone(criteria); // Paging. recordsCriteria.SetFirstResult(pageIndex * pageSize); recordsCriteria.SetMaxResults(pageSize); // Count criteria. ICriteria countCriteria = CriteriaTransformer.TransformToRowCount(criteria); // Perform multi criteria to get both results and count in one trip to the database. IMultiCriteria multiCriteria = Session.CreateMultiCriteria(); multiCriteria.Add(recordsCriteria); multiCriteria.Add(countCriteria); IList multiResult = multiCriteria.List(); IList untypedRecords = multiResult[0] as IList; IList<T> records = new List<T>(); if (untypedRecords != null) { foreach (T obj in untypedRecords) { records.Add(obj); } } else { records = new List<T>(); } totalCount = Convert.ToInt64(((IList)multiResult[1])[0]); return records; } 

It clones your original criteria twice: one criterion that returns records for the page and one criterion for the total number of records. It also uses IMultiCriteria to make both database calls in one reverse direction.

Answer 2

He has a job, but two challenges

I added itemCount to the link:

 itemCount = (Int64)_session.CreateQuery("select count(UserId) from User") .UniqueResult();