Mapping enum with fluent nhibernate

问题:

I am following the http://wiki.fluentnhibernate.org/Getting_started tutorial to create my first NHibernate project with Fluent NHibernate

I have 2 tables

1) Account with fields

Id
AccountHolderName
AccountTypeId

2) AccountType with fields

Id
AccountTypeName

Right now the account types can be Savings or Current So the table AccountTypes stores 2 rows 1 - Savings 2 - Current

For AccoutType table I have defined enum

public enum AccountType {
    Savings=1,
    Current=2
}

For Account table I define the entity class

public class Account {
    public virtual int Id {get; private set;}
    public virtual string AccountHolderName {get; set;}
    public virtual string AccountType {get; set;}
}

The fluent nhibernate mappings are:

public AgencyMap() {
    Id(o => o.Id);
    Map(o => o.AccountHolderName);
    Map(o => o.AccountType);
}

When I try to run the solution, it gives an exception - InnerException = {"(XmlDocument)(2,4): XML validation error: The element 'class' in namespace 'urn:nhibernate-mapping-2.2' has incomplete content. List of possible elements expected: 'meta, subselect, cache, synchronize, comment, tuplizer, id, composite-id' in namespace 'ur...

I guess that is because I have not speciofied any mapping for AccountType.

The questions are:

1. How can I use AccountType enum instead of a AccountType class?
2. Maybe I am going on wrong track. Is there a better way to do this?

Thanks!

回答1:

The following apparently no longer works https://stackoverflow.com/a/503327/189412

How about just doing this:

public AgencyMap() {
    Id(o => o.Id);
    Map(o => o.AccountHolderName);
    Map(o => o.AccountType).CustomType<AccountType>();
}

The custom type handles everything :)

回答2:

public class Account {
    public virtual int Id {get; private set;}
    public virtual string AccountHolderName {get; set;}
    public virtual AccountType AccountType {get; set;}
}

public AgencyMap() {
    Id(o => o.Id);
    Map(o => o.AccountHolderName);
    Map(o => o.AccountType);
}

Fluent NHibernate saves enum values as string by default if you want to override that you need to supply a convention for it. Something like:

public class EnumConvention :
    IPropertyConvention, 
    IPropertyConventionAcceptance
{
    #region IPropertyConvention Members

    public void Apply(IPropertyInstance instance)
    {
        instance.CustomType(instance.Property.PropertyType);
    }

    #endregion

    #region IPropertyConventionAcceptance Members

    public void Accept(IAcceptanceCriteria<IPropertyInspector> criteria)
    {
        criteria.Expect(x => x.Property.PropertyType.IsEnum ||
        (x.Property.PropertyType.IsGenericType && 
         x.Property.PropertyType.GetGenericTypeDefinition() == typeof(Nullable<>) &&
         x.Property.PropertyType.GetGenericArguments()[0].IsEnum)
        );
    }

    #endregion
}

Almost forgot that you need to add the convention to your fluent config as well. You do that at the same place you add the mappings:

.Mappings(m => m.FluentMappings.AddFromAssemblyOf<BillingRecordMap>()
.Conventions.AddFromAssemblyOf<EnumConvention>()

回答3:

A Great way to do this, is implement the interface IUserType and Create a CustomType with the rules to write and read, that´s a example to boolean:

 public class CharToBoolean : IUserType
{
    public SqlType[] SqlTypes => new[] { NHibernateUtil.String.SqlType };

    public Type ReturnedType => typeof(bool);

    public bool IsMutable =>true;

    public object Assemble(object cached, object owner)
    {
        return (cached);
    }

    public object DeepCopy(object value)
    {
        return (value);
    }

    public object Disassemble(object value)
    {
        return (value);
    }

    public new bool Equals(object x, object y)
    {
        if (ReferenceEquals(x, y)) return true;

        var firstObject = x as string;
        var secondObject = y as string;

        if (string.IsNullOrEmpty(firstObject) || string.IsNullOrEmpty(secondObject)) return false;

        if (firstObject == secondObject) return true;
        return false;
    }

    public int GetHashCode(object x)
    {
        return ((x != null) ? x.GetHashCode() : 0);
    }

    public object NullSafeGet(IDataReader rs, string[] names, object owner)
    {
        var obj = NHibernateUtil.String.NullSafeGet(rs, names[0]);

        if (obj == null) return null;

        var value = (string)obj;

        return value.ToBoolean();
    }

    public void NullSafeSet(IDbCommand cmd, object value, int index)
    {
        if(value != null)
        {
            if ((bool)value)
            {
                ((IDataParameter)cmd.Parameters[index]).Value = "S";
            }
            else
            {
                ((IDataParameter)cmd.Parameters[index]).Value = "N";
            }
        }
        else
        {
            ((IDataParameter)cmd.Parameters[index]).Value = DBNull.Value;
        }
    }
    public object Replace(object original, object target, object owner)
    {
        return original;
    }
}

}

the mapping:

  this.Map(x => x.DominioGenerico).Column("fldominiogen").CustomType<CharToBoolean>();

It´s a sample but you can do this with other types.