OData v4 filter query fails when using contains on calculated property

Question

So I have a code first EF 6 layer which has a Contact class of:

public class Contact
{
    [Key]
    public int Id { get; set; }

    [MaxLength(50)]
    public string Prefix { get; set; }

    [MaxLength(50)]
    public string Suffix { get; set; }

    [MaxLength(50)]
    public string FirstName { get; set; }

    [MaxLength(50)]
    public string MiddleName { get; set; }

    [MaxLength(50)]
    public string LastName { get; set; }

    [NotMapped]
    [DisplayName("Full Name")]
    public string FullName
    {
        get
        {
            string tempName =
                (!string.IsNullOrEmpty(Prefix) ? Prefix + " " : "") +
                (!string.IsNullOrEmpty(FirstName) ? FirstName + " " : "") +
                (!string.IsNullOrEmpty(MiddleName) ? MiddleName + " " : "") +
                (!string.IsNullOrEmpty(LastName) ? LastName + " " : "") +
                (!string.IsNullOrEmpty(Suffix) ? Suffix + " " : "");
            return tempName.Trim();
        }
    }

    [MaxLength(50)]
    public string JobTitle { get; set; }

    public bool? Primary { get; set; }
    public bool? Inactive { get; set; }

    public int? Customer_Id { get; set; }

    [ForeignKey("Customer_Id")]
    public virtual Customer Customer { get; set; }

    public virtual ICollection<Email> Emails { get; set; }
    public virtual ICollection<Address> Addresses { get; set; }
    public virtual ICollection<PhoneNumber> PhoneNumbers { get; set; }
    public virtual ICollection<Note> Notes { get; set; }
}

I have an ASP.NET Web API 2 service running that offers up a list of contacts, but when I perform an OData query of $filter=contains(tolower(FullName), tolower('smith')) I get a BadRequest response. I verified in the WebAPI get method that it is successfully getting results from the database, but it sends back a BadRequest error.

It definitely has something to do with the FullName field either being a calculated field or because it has the NotMapped attribute. When I change the OData query to $filter=contains(tolower(LastName), tolower('smith')) it works fine. I also tried using the display name of "Full Name" in the query instead of "FullName" and that too did not work.

Is there something I need to do to make OData play nice with a calculated or notmapped field?

Answer 1

Implement an OData function on your ContactsController that takes a string for comparison and returns the filtered set of Contacts. Something like:

    [HttpGet]
    [ODataRoute("Contacts/Default.FullNameContains(value={value})")]
    public IHttpActionResult FullNameContains(string value)
    {
        value = value.ToLower();
        return Ok(db.Contacts.ToList().Where(c => c.FullName.Contains(value)));
    }

Because FullName is computed, the function must perform the filtering in memory.