在实体POCO中使用自定义数据类型？

Question

I have a business object, say a User . A User has a PhoneNumber field, which is represented by a string. I, for reasons best left to me, have created a PhoneNumber class that has implicit to/from string operators. Do I have to do anything special to get the PhoneNumber written as a string to the database? Right now, Entity has decided to break my PhoneNumber class up into its constituent parts ( AreaCode , Prefix , etc) and save those to the database individually. PhoneNumber is stored in a separate assembly.

public class PhoneNumber : IEquatable<PhoneNumber>, IComparable<PhoneNumber>
{
    public static implicit operator string (PhoneNumber ph)
    {
        return ph.ToString ();
    }

    public static implicit operator PhoneNumber (string number)
    {
        return Parse(number);
    }

    public static PhoneNumber Parse(string number)
    {
       // ...
    }

    public override string ToString ()
    {
        // produce a Parse-compatible output
    }
}

public class User
{
    public virtual int Id { get; set; }
    public virtual string FirstName { get; set; }
    public virtual PhoneNumber Phone { get; set; }
}

public class MyContext : DbContext
{
    public DbSet<User> Users { get; set; }
}

Answer 1

The only way is a workaround like this:

// You want to store in same table and not a navigation property, right?
// Then you need [ComplexType]
[ComplexType] 
public class PhoneNumber : IEquatable<PhoneNumber>, IComparable<PhoneNumber>
{
    // ...

    public string FullNumber
    {
        get
        {
            return Prefix + "-" + AreaCode + " " + Number; // or whatever
        }
        set
        {
            AreaCode = ParseToAreaCode(value); // or so...
            Prefix = ParseToPrefix(value);     // or so...
            Number = ParseToNumber(value);     // or so...
        }
    }

    [NotMapped]
    public string AreaCode { get; set; }
    [NotMapped]
    public string Prefix { get; set; }
    [NotMapped]
    public string Number { get; set; }
}

This way you would get only a FullNumber column in the database.

Answer 2

If the rest of your design allows it, you could leave the PhoneNumber class out of the mapping and let User handle a string representation of it, like:

public class User
{
  public virtual int Id { get; set; }
  public virtual string FirstName { get; set; }

  public virtual string PhoneNumber
  { 
      get { return this.PhoneNumber.ToString(); } // TODO: check for null
      set { this.PhoneNumber = PhoneNumber.Parse(value); }
  }

  [NotMapped]
  public virtual PhoneNumber Phone { get; set; }
}