Question

I have a dictionary in my class

public class AffectedVehicleInScenario : DomainObjectWithId {

    ... some other properties ...

    private readonly int _id;
    private readonly IDictionary<int, int> _installationRates
        = new Dictionary<int, int>();

    ... some code ...

}

and mapped it as follows

<class name="AffectedVehicleInScenario"
     table="tblAffectedVehicleInScenario"
     lazy="false">
<id name="_id"
    column="Id"
    access="field">
  <generator class="native" />
</id>

... some other properties ...

<map name="_installationRates"
     table="tblInstallationRatesOfAffectedVehicleInScenario"
     access="field"
     lazy="false">
  <key column="AffectedVehicleInScenarioId" not-null="true"/>
  <index column="Year" type="Int32"/>
  <element column="InstallationRate"
           not-null="true" 
           type="Int32"/>
</map>

Inserting works perfect but when loading from database (SQLITE) I get an exception:

Spring.Data.NHibernate.HibernateSystemException: could not initialize a collection:
[Com.QueoMedia.CO2Simulationstool.Domain.AffectedVehicleInScenario._installationRates#1][SQL: SELECT installat0_.AffectedVehicleInScenarioId as Affected1_0_, installat0_.InstallationRate as Installa2_0_, installat0_.Year as Year0_ FROM tblInstallationRatesOfAffectedVehicleInScenario installat0_ WHERE installat0_.AffectedVehicleInScenarioId=?]
---> NHibernate.Exceptions.GenericADOException: could not initialize a collection:
[Com.QueoMedia.CO2Simulationstool.Domain.AffectedVehicleInScenario._installationRates#1][SQL: SELECT installat0_.AffectedVehicleInScenarioId as Affected1_0_, installat0_.InstallationRate as Installa2_0_, installat0_.Year as Year0_ FROM tblInstallationRatesOfAffectedVehicleInScenario installat0_ WHERE installat0_.AffectedVehicleInScenarioId=?]
---> System.InvalidCastException: Die angegebene Umwandlung ist ungültig.

Could someone help me out please? Is the mapping incorrect or is it a bug in nhibernate?

Thanks in advance

Tobi

Update:
The Created table is the following:

CREATE TABLE tblInstallationRatesOfAffectedVehicleInScenario
(
    AffectedVehicleInScenarioId INT not null,
    InstallationRate SMALLINT not null,
    Year INT not null,
    primary key (AffectedVehicleInScenarioId, Year),
    constraint FKDF60481555A07D7C foreign key (AffectedVehicleInScenarioId) references tblAffectedVehicleInScenario
)

Answer 1

i guess it is because sqlite driver returns a short boxed as object which is not directly convertable to int. you could use IDictionary<int, short> or use implement IUserType or there maybe some config to tell NH the difference.