The DataAnnotations [Phone] Attribute

Question

What is the default, valid format of the [Phone] attribute? In the data table, the phone column is navrchar (16) If I enter a phone # like 1112223333, I get "field is not a valid phone number." If I enter 01112223333, I get "The value '11112223333' is invalid."

Also, how to override it? I understand that I could do something like this, but is this the best practice in this case?

[RegularExpression(@"((\(\d{3}\) ?)|(\d{3}-))?\d{3}-\d{4}",ErrorMessage="Invalid Phone Number!")]

Related code:

    [Required]
    [Phone]
    public string Phone { get; set; }

    <div class="editor-field">
       @Html.EditorFor(model => model.Phone)
       @Html.ValidationMessageFor(model => model.Phone)
    </div>

Update I guess there was a mapping issue when I changed the phone column from int to navrchar. Updating the model was not enough, so I had to change the value manually using the Table Mapping.

Error 2019: Member Mapping specified is not valid. The type 'Edm.Int32[Nullable=False,DefaultValue=]' of member 'Phone' in type 'UserDBModel.UserProfile' is not compatible with 'SqlServerCe.nvarchar[Nullable=False,DefaultValue=,MaxLength=16,Unicode=True,FixedLength=False]' of member 'Phone' in type 'UserDBModel.Store.UserProfile'.

Answer 1

The default regular expression for the PhoneAttribute can now be handily found by browsing the source code with .NET Reference Source (.NET Framework 2.7.2) or source.dot.net (.NET Core)

There it shows the (ugly) Regex as being defined as:

private static Regex _regex = new Regex(@"^(\+\s?)?((?<!\+.*)\(\+?\d+([\s\-\.]?\d+)?\)|\d+)([\s\-\.]?(\(\d+([\s\-\.]?\d+)?\)|\d+))*(\s?(x|ext\.?)\s?\d+)?$", RegexOptions.Compiled | RegexOptions.IgnoreCase | RegexOptions.ExplicitCapture);

That answers your direct question, but whether it helps or not remains to be seen. Maybe it would be a good base to create your own modified phone number regex.