NHibernate Map class name and resolve it with Reflection
I have a property of a class that is mapped to another class that can't be stored in the database and can't be serialized; it implements the state pattern. So I have something like this:
public IState MyState { get; set; }
Where I have two differ开发者_StackOverflow中文版ent states
public class LockedState : IState ...
public class UnlockedState : IState ...
In the database I need to persist the name of the current state that can be accomplished using, for example:
string name = myState.GetType().Name;
Do I have to write a custom and verbose IUserState or is there anything around?
In order to do that I had to implement a custom IUserType in the following way:
public sealed class StateMapper : IUserType
// get
public object NullSafeGet(IDataReader rs, string[] names, object owner)
{
string objectName = (string)NHibernateUtil.String.NullSafeGet(rs, names[0]);
Type stateType = Type.GetType(objectName, false, true);
if (stateType == null)
{
return null;
}
// StateFacility is used by my code to create a new Type
return StateFacility.CreateState(stateType);
}
// set
public void NullSafeSet(IDbCommand cmd, object value, int index)
{
if (value == null)
{
NHibernateUtil.String.NullSafeSet(cmd, null, index);
return;
}
NHibernateUtil.String.NullSafeSet(cmd, value, index);
}
精彩评论