nhibernate 3不支持指定的方法

Question

i recently migrated from nhibernate 2 to 3, the problem i have is , in most of query i had before i have a problem right now. and i see this error Specified method is not supported although they all work well in hibernate 2 . one on these query is like this

 public JsonResult AllEducationDegree(string search)
    {
        var data = Repository<EducationDegree>
          .FindBySpecification(new EducationDegreeSpecification().Search(search))
          .Take(10)
          .Select(p => new NameValue(p.Title, (int)p.Id))
          .ToList();
         // .AsDropdown(" ");
        return Json(data, JsonRequestBehavior.AllowGet);
    }

public class EducationDegreeSpecification : FluentSpecification<EducationDegree>
{
    public EducationDegreeSpecification Search(string EducationDegreeSearch)
    {
        if (!String.IsNullOrEmpty(EducationDegreeSearch))
        {
            string[] searchs = EducationDegreeSearch.Split(' ');
            foreach (string search in searchs)
            {
                if (!String.IsNullOrEmpty(search))
                {
                    AddExpression(p => p.Title.Contains(search));
                }
            }
        }
        return this;
    }

}

Answer 1

You need to select before Take. It should work.

   var data = Repository<EducationDegree>
      .FindBySpecification(new EducationDegreeSpecification().Search(search))
      .Select(p => new NameValue(p.Title, (int)p.Id))
      .Take(10)
      .ToList();
     // .AsDropdown(" ");
    return Json(data, JsonRequestBehavior.AllowGet);

Answer 2

In the last few lines...

AddExpression(p => p.Title.Contains(search));

if p.Title is null, then you'd get "specific method is not supported." You could try writing

AddExpression(p => p.Title != null && p.Title.Contains(search));

or using C# 6

AddExpression(p => p.Title?.Contains(search));

Answer 3

I just have similar problem, and it happen because property, which was mapped as "many-to-one" have attribute lazy="no-proxy". I removed that, and it works. Problem is probably because this property was used in where part of query. Like:

 EntityType aliasEntityType = null;
 PropertyType aliasPropertyType = null; 

 QueryOver.Of<EntityType>(() => aliasEntityType)
 .JoinAlias(() => aliasEntityType.Property, () => aliasPropertyType)
 .Where(() => aliasPropertyType.SomeValue == someValue)
 ....

So, Property of type PropertyType shouldn't have lazy="no-proxy". I have tried to implicitly fetch Property, but it doesn't work.