Telephone Number Model to match database with NUMBER(10) phone field.

PhoneModel.cs

public class PhoneModel
{
    public long PhoneNumber { get; set; }

    private string _phoneString;

    [DataType(DataType.PhoneNumber)]
    public string PhoneString
    {
        get
        {
            if (!string.IsNullOrWhiteSpace(_phoneString))
                return _phoneString;

            return DisplayPhoneNumber;
        }

        set
        {                
            _phoneString = value ?? string.Empty;        

            if (value != null)        
                PhoneNumber = Convert.ToInt64(Regex.Replace(_phoneString, @"[\(\)\-\ ]", string.Empty));
        }
    }

    public string DisplayPhoneNumber => PhoneNumber > 0 ? string.Format("{0:(###) ###-####}", PhoneNumber) : string.Empty;
}