How to store double[] array to database with Entity Framework Code-First approach

You can do a thing like this :

    [NotMapped]
    public double[] Data
    {
        get
        {
            string[] tab = this.InternalData.Split(',');
            return new double[] { double.Parse(tab[0]), double.Parse(tab[1]) };
        }
        set
        {
            this.InternalData = string.Format("{0},{1}", value[0], value[1]);
        }
    }

    [EditorBrowsable(EditorBrowsableState.Never)]
    public string InternalData { get; set; }

Thank you all for your inputs, due to your help I was able to track down the best way to solve this. Which is:

 public string InternalData { get; set; }
 public double[] Data
 {
    get
    {
        return Array.ConvertAll(InternalData.Split(';'), Double.Parse);                
    }
    set
    {
        _data = value;
        InternalData = String.Join(";", _data.Select(p => p.ToString()).ToArray());
    }
 }

Thanks to these stackoverflow posts: String to Doubles array and Array of Doubles to a String

I know it is a bit expensive, but you could do this

class Primitive
{
    public int PrimitiveId { get; set; }
    public double Data { get; set; }

    [Required]
    public Reference ReferenceClass { get; set; }
}

// This is the class that requires an array of doubles
class Reference
{
    // Other EF stuff

    // EF-acceptable reference to an 'array' of doubles
    public virtual List<Primitive> Data { get; set; }
}

This will now map a single entity (here 'Reference') to a 'list' of your Primitive class. This is basically to allow the SQL database to be happy, and allow you to use your list of data appropriately.

This may not suit your needs, but will be a way to make EF happy.