How to configure Automapper to automatically ignore properties with ReadOnly attribute?

Question

Context:

Let's say I have the following "destination" class:

public class Destination {     public String WritableProperty { get; set; }      public String ReadOnlyProperty { get; set; } } 

and a "source" class with the ReadOnly attribute on one of it's properties:

public class Source {     public String WritableProperty { get; set; }      [ReadOnly(true)]     public String ReadOnlyProperty { get; set; } } 

It's obvious, but to be clear: I am going to map from Source class to Destination class in the following way:

Mapper.Map(source, destination); 

Problem:

What are the ways to configure Automapper to automatically ignore property with ReadOnly(true) attribute?

Constraints:

I use Automapper's Profile classes for configuration. I don't want to dirty up classes with Automapper-specific attributes. I don't want to configure Automapper for every single read-only property and cause a lot of duplication by this way.

Possible (but not suited) solutions:

1) Add attribute IgnoreMap to the property:

    [ReadOnly(true)]     [IgnoreMap]     public String ReadOnlyProperty { get; set; } 

I don't want to dirty up classes with automapper-specific attributes and make it dependent from it. Also I don't want to add additional attribute along with ReadOnly attribute.

2) Configure Automapper to ignore the property:

CreateMap<Source, Destination>() .ForSourceMember(src => src.ReadOnlyProperty, opt => opt.Ignore()) 

It is not a way because it forces me to do that for every single property everywhere and also causes a lot of duplication.

Answer 1

Write Extension Method as shown below:

public static class IgnoreReadOnlyExtensions {     public static IMappingExpression<TSource, TDestination> IgnoreReadOnly<TSource, TDestination>(                this IMappingExpression<TSource, TDestination> expression)     {         var sourceType = typeof(TSource);          foreach (var property in sourceType.GetProperties())         {             PropertyDescriptor descriptor = TypeDescriptor.GetProperties(sourceType)[property.Name];             ReadOnlyAttribute attribute = (ReadOnlyAttribute) descriptor.Attributes[typeof(ReadOnlyAttribute)];             if(attribute.IsReadOnly == true)                 expression.ForMember(property.Name, opt => opt.Ignore());         }         return expression;     } } 

To call extension method:

Mapper.CreateMap<ViewModel, DomainModel>().IgnoreReadOnly();