http://docs.automapper.org/en/stable/Value-converters.html

public class CurrencyFormatter : IValueConverter<decimal, string> {

    public string Convert(decimal source)
        => source.ToString("c");
}

 cfg.CreateMap<Order, OrderDto>()
       .ForMember(d => d.Amount, opt => opt.ConvertUsing(new CurrencyFormatter()));

转换器 与 解释器 区别

• Type converter = Func<TSource, TDestination, TDestination>  // 全局
• Value resolver = Func<TSource, TDestination, TDestinationMember>  // 
• Member value resolver = Func<TSource, TDestination, TSourceMember, TDestinationMember>
• Value converter = Func<TSourceMember, TDestinationMember>  //只与成员相关

AutoMapper 值转换器