错误：值“ System.Object []”不是类型“ prjCustomerService.clsCustomer”，因此不能在此通用集合中使用。 参数名称：值

Question

public IList<CustomerData> StoredProcedure(int CID)
    {
        IList<CustomerData> lObjEmployees = new List<CustomerData>();
        NHibernate.Cfg.Configuration lObjConfig = new NHibernate.Cfg.Configuration();
        lObjConfig.AddAssembly("prjCustomerService");
        NHibernate.ISessionFactory lObjFactory = lObjConfig.BuildSessionFactory();
        NHibernate.ISession lObjSession = lObjFactory.OpenSession();
        NHibernate.IQuery lObjQuery = lObjSession.GetNamedQuery("Test1");
        lObjQuery.SetInt32("CID", @CID);
        IList<clsCustomer> lObjEmpList = lObjQuery.List<clsCustomer>();
        foreach (clsCustomer lObjCurrEmployee in lObjEmpList)
        {
            CustomerData lObjCurrEmpData = new CustomerData();
            lObjCurrEmpData.CID = lObjCurrEmployee.CID;
            lObjCurrEmpData.CName = lObjCurrEmployee.CName;
            lObjCurrEmpData.Cadd = lObjCurrEmployee.CAdd;
            lObjCurrEmpData.Ccontact = lObjCurrEmployee.CContact;
            lObjEmployees.Add(lObjCurrEmpData);
        }
     return lObjEmployees;
    }

This is my WCF service code.I get an error at line:

IList<clsCustomer> lObjEmpList = lObjQuery.List<clsCustomer>();

The value "System.Object[]" is not of type "prjCustomerService.clsCustomer" and cannot be used in this generic collection.

Parameter name: value

Test1 is my stored procedure and it returns a row where CID="xyz" .

Answer 1

In my case, the alias that I was using to select in the QueryOver was different from what I was actually "selecting as":

The Query (notice the with alias ):

IndividualBugViewModel individualBugViewModelAlias = null;

IQueryOver<DomainModel.Models.Bug, DomainModel.Models.Bug> bugQueryOver = Repository
    .QueryOver(() => bugAlias)
    .SelectList(list => list.SelectGroup(() => bugAlias.Details).WithAlias(
                            () => individualBugViewModelAlias.Details)

The Result:

var bugList = bugQueryOver.List() //Error!

Because, when running the query, I was not passing the class type into which the result should be transformed to, it would try to transform the result into type DomainModel.Models.Bug instead of IndividualBugViewModel . This resulted into the error.

So I changed it to:

var bugList = bugQueryOver.TransformUsing(Transformers.AliasToBean<IndividualBugViewModel>())
                 .List<IndividualBugViewModel>();

In your case, the <return class="className"> in your named query must be incompatible with clsCustomer .

Answer 2

Try:

IList<clsCustomer> lObjEmpList = lObjQuery.OfType<clsCustomer>.ToList();

Remember to add using System.Linq to your using statements.

With this statement your say that your non-generic IQuery must be filtered to contain only clsCustomer objects, then with .ToList you say that you want to create a list out of it.