title: ASP.NET MVC 3 Data Annotation for Mobile and Phone Numbers (Edited)
body: <p>How can I write the validation using data annotation in writing telephone number such as "094-4567" or mobile number such as "09129705678" etc.?</p>
  
  <pre><code>using System.Web;
  using System.Data.Entity;
  using System.ComponentModel.DataAnnotations;
  
  namespace PhoneBook.Models
  {
      public class Contact
      {
          [Required(ErrorMessage="Telephone Number Required")
          [?]
          public string Telephone Number {get; set;}
      }
  }
  </code></pre>
  
  <p>I really don't know what to do...</p>