EF Code First - Map Dictionary or custom type as an nvarchar

Question

I want to use EF Code first for a database that I'm currently accessing using plain old ADO.NET with stored procedures.

In my database I have some nvarchar(MAX) columns that should be mapped to and from a Dictionary<string, string>.

When saved to database, it is an XML formatted string. I use this technique to allow internationalization of e.g. a name of a product in an online store. I don't know how many languages any given user want to translate to so I can't have a Name column for each language.

I also wanted to avoid storing the values in a seperate table, so I ended up with the Dictionary - XML approach.

The way I do it now, is to just treat any of these columns as a string whenever I interact with the database. I have a custom mapper function that can turn the XML into a Dictionary, and back to XML.

But I can't seem to find a way to do this with EF Code first? Any ideas?

Answer 1

You can add a property that will return your Dictionary<,> as a XML string and then remove the mapping for your Dictionary<,> property.

    [NotMapped]
    public Dictionary<string,string> MyDictionary
    {
     get; set;
    }

    public string DictionaryAsXml
    {
        get
        {
             return ToXml(MyDictionary);
        }
        set
        {
           MyDictionary = FromXml(value);
        }
    }

If you don't want to expose your DictionaryAsXml property have a look at this blog post. It shows how you can persist private and protected properties.