Automapper handling custom made exceptions so can't handle them elsewhere

Question

I am throwing custom exceptions inside my resolvers, but they are being caught and wrapped by Automapper so we cant handle them elsewhere in the program. I've included a simple example of the problem, the desired outcome is to catch an InterfaceError but it only catches an AutoMapperException with the InterfaceError as an inner exception.

In class:

public Order MapOrder(InterfaceOrder iOrder)
{
    try
    {
        Order mappedOrder = Mapper.Map<InterfaceOrder, Order>(iOrder);
    }
    catch (InterfaceException ex)
    {
        Log("Interface error");
    }
    catch (Exception ex) 
    {
        Log("error");  
    }

    return mappedOrder;
}

Mapping:

Mapper.CreateMap<InterfaceOrder, Order>()                
      .ForMember(c => c.Name, op => op.ResolveUsing(data =>
        {
            if (Name.Length > 50) 
            { 
                throw new InterfaceException("Error!", ex);                                                                   
            }
            else 
            {
                return c.Name
            }
        }));

Answer 1

Automapper doesn't let an exception escape directly from the mapping process, but tries and wrap it in its own Exception as you noticed. Your best bet would be to wrap the call to Map inside a function that catches AutoMapperMappingException and unwrap it

public ToClass Map<FromClass, ToClass>(FromClass fc)
{
    try
    {
        return Mapper.Map<FromClass, ToClass>(fc);
    }
    catch(AutoMapperMappingException autoMapperException)
    {
        throw autoMapperException.InnerException; 
        // this will break your call stack
        // you may not know where the error is called and rather
        // want to clone the InnerException or throw a brand new Exception
    }
}