How do I map a dictionary using Fluent NHibernate automapping?

Question

I have an entity like so:

public class Land
{
    public virtual IDictionary<string, int> Damages { get; set; }
    // and other properties
}

Every time I try to use automapping with the following code:

var sessionFactory = Fluently.Configure()
    .Database(SQLiteConfiguration.Standard.InMemory)
    .Mappings(m => m.AutoMappings.Add(AutoMap.AssemblyOf<Land>))
    .BuildSessionFactory();

I get the following error:

{"The type or method has 2 generic parameter(s), but 1 generic argument(s) were
provided. A generic argument must be provided for each generic parameter."}

Can someone tell me what I'm doing wrong? Also, this is just a simple example. I have much more dictionaries than just this one.

http://stackoverflow.com/questions/1410716/fluentnhibernate-mapping-for-dictionary Try AsMap() — mokha, Sep 14 '12 at 16:38

score 8 · Accepted Answer · answered Dec 30 '09 at 09:28

8

It is impossible with NHibernate.

answered Dec 30 '09 at 09:28

user224564

1,313
1
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Do you mean this to be impossible with Fluent NHibernate automapping, Fluent NHibernate as a whole (meaning with the fluent mappings as well), or NHibernate itself? – Daniel T. Jan 01 '10 at 02:05
NHibernate itself. I do not know any ORM that could automap dictionary at present moment. – user224564 Jan 03 '10 at 06:06
8

You're right, you have to manually map it. Using Fluent, it'd be `References(x => x.Dictionary).AsMap("keyColumn").Element("valueColumn", c => c.Type());`. – Daniel T. Jan 11 '10 at 05:18

score 3 · Answer 2 · edited May 23 '17 at 12:01

3

Found some traces that this isn't possible. Some traces, that it's recently implemented.

Still investigating. :)

This looks quite promising (didn't test yet).

So, in your case it should look like=>

public class LandMap : ClassMap<Land>
{
    public LandMap()
    {
        (...)

        HasMany(x => x.Damages)
            .WithTableName("Damages")
            .KeyColumnNames.Add("LandId")
            .Cascade.All()
            .AsMap<string>(
                index => index.WithColumn("DamageType").WithType<string>(),
                element => element.WithColumn("Amount").WithType<int>()
            );
    }
}

Keep in mind - it should. I didn't test it.

edited May 23 '17 at 12:01

Community

1
1

answered Dec 23 '09 at 23:09

Arnis Lapsa

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That's for fluent mapping. I'm looking for something that works for automapping because I have about 50 dictionaries across all my entities. – Daniel T. Dec 23 '09 at 23:15
Ahhh... sorry. Somehow didn't notice `automapping`. I'll take a look. :) – Arnis Lapsa Dec 23 '09 at 23:18

score 1 · Answer 3 · answered Sep 29 '10 at 06:55

1

A possible workaround that should in theory work with automapping:

public class DamagesDictionary : Dictionary<string, int>
{
}

Land.cs

public class Land
{
   public virtual DamagesDictionary Damages { get; set; }
   // and other properties
}

or a more generic approach...

public class StringKeyedDictionary<T> : Dictionary<string, T>
{
}

Land.cs

public class Land
{
   public virtual StringKeyedDictionary<int> Damages { get; set; }
   // and other properties
}

answered Sep 29 '10 at 06:55

Josef P.

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1
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I think this is an underrated answer - simpler sometimes to make another POCO with 2 properties on it (Key, Value) and reference that if you can't be bothered to write the mappings (Lazy, yes.. Recommender, no... but...) – Darbio Nov 30 '11 at 05:01

How do I map a dictionary using Fluent NHibernate automapping?

3 Answers3

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