Fluent NHibernat - Querying enum field with LINQ

Question

My application has the following database structure:

Transactions:
- TransactionID (PK, Identity, Int)
- TypeID (FK, Int)
- Amount (Decimal)

TransactionTypes:
- TypeID (PK, Identity, Int)
- Type (NVarChar)

They are defined in my application as:

public class Transaction
{
    public virtual int TransactionID { get; set; }
    public virtual TransactionTypes Type { get; set; }
    public virtual decimal Amount { get; set; }
}

public enum TransactionTypes
{
    Event = 1,
    Product = 2
}

With the following mapping:

public class TransactionMap : ClassMap<Transaction>
{
    public TransactionMap()
    {
        Table("Transactions");
        Id(x => x.TransactionID);
        Map(x => x.Type, "TypeID").CustomType<int>();
        Map(x => x.Amount);
    }
}

Everything works fine apart from querying. When i try doing:

session.Linq<Transaction>().Where(t => t.Type == TransactionTypes.Event).ToList();

It throws the error "Type mismatch in NHibernate.Criterion.SimpleExpression: Type expected type System.Int32, actual type Entities.TransactionTypes".

I'd appreciate it if someone could show me the correct way to map this. Thanks

Answer 1

The best way to map enums in Fluent NHibernate is by using conventions. See these two threads for help:

Mapping enum with fluent nhibernate

How do you map an enum as an int value with fluent NHibernate?