Question

Is there any way to map a dictionary using Entity Framework 5?

From what I found while searching, it has not been supported until EF 4.1, not sure if EF 5 provides any innovative methods to map it easily.

I am using the dictionary to store a “variable number of properties” for each object of a class.

If it’s not supported what would be the best alternative data structure to use in this scenario (supported by EF)?

Answer 1

No dictionary is still not supported. You must use traditional one-to-many relation. Where each your current key/value pair in dictionary will be stored as record in table and related with foreign key to principal entity (that one which contained the dictionary). The entity should look like:

public class Item {
    public int Id { get; set; } // unique autogenerated database key
    public string Key { get; set; }
    public string Value { get; set; }
    public int PrincipalId { get; set; } // FK to principal entity
}

Types of properties and name of foreign key will differ for your current situation. The principal entity will just have:

public virtual ICollection<Item> Items { get; set; }