Question

I’m working on a rather large Asp.net MVC3 project and would like to use Automapper to solve the following problem.

In the database, phone numbers are stored as a 10 digit decimal number. On the user screen, they are displayed & edited as “(xxx) yyy-zzzz”.

What I want to do is to create a custom type converter that would look like follows –

public class phoneNumber  //display data type
                inherits string;

public class getdata(){
       Mapper.CreateMap<decimal, phoneNumber>().ConvertUsing(decimal2Phone);
       Mapper.CreateMap<phoneNumber, decimal>().ConvertUsing(phone2Decimal);

       Mapper.CreateMap<dbRecordTYpe, displayRecordType>();
       Mapper.CreateMap<displayRecordType, dbRecordTYpe>();
}

Where the usage is like on https://github.com/AutoMapper/AutoMapper/wiki/Custom-type-converters. We are using Automapper to move all of our data from the database entity models to display view models.

I know that I cannot inherit from string.

However, If I can do this this format conversion using Automapper, it will save me a lot work work and duplicate code.

Answer 1

You can use a composition instead of inheritance – just use a string property in a custom PhoneNumber class and use that property in the mapping:

class PhoneNumber
{
  public string Number {get;set;}
}

...
Mapper.CreateMap<decimal, PhoneNumber>().ConvertUsing( num =>
{
   //do custom conversion of decimal to string here, ToString() just example
   string s = num.ToString();
   return new PhoneNumber() { Number =  s };
});