mapping System.Type as a property, to a string column

derickbailey · **Joined:** Fri Aug 03, 2007 4:44 pm **Posts:** 6

Has anyone been able to map a property of type "System.Type" to a database column of a string type, and do searches against it?

Specifically, i'm using SQLite and a Text column. This is the class / mapping that I have:

... class
public class MyObject
{
private Type _objectType;
public Type ObjectType
{
get { return _objectType; }
set { _objectType = value; }
}
}

... mapping
<property name="ObjectType" type="System.Type" />

when I try to do searches against this specific column, I constantly get an Object reference error:

NHibernate.Util.ADOExceptionReporter - Object reference not set to an instance of an object.

NHibernate.ADOException: could not execute query
[ SELECT this_.Id as Id32_0_, this_.MessageType as MessageT2_32_0_, this_.Message as Message32_0_, this_.Status as Status32_0_, this_.ObjectId as ObjectId32_0_, this_.ObjectType as ObjectType32_0_ FROM Messages this_ WHERE this_.ObjectType = ? ]
Positional parameters: 0 null

... it seems that i always end up with a null parameter... i've tried implementing a custom IUserType and I end up with the same thing. Ideas?

mnichols · **Joined:** Mon Aug 21, 2006 9:18 am **Posts:** 179

Get rid of the 'type' atribute in this:

Code:

and let NHibernate deal with it. It will write the fully qualified type name (MyAssembly.MyNamespace.MyObject,MyAssembly) as a string column (nvarchar) and then will do the conversion in your biz object for you when it is hydrated/persisted.
Mike