passing around values to an AutoMapper Type Converter from outside

问题:

I have a multilingual database, which returns values based on a key and an enum Language. When I convert a DB object to a model, I want the model to contain the translated value based on the key and the current language.

The key comes from the DB object but how can I pass the current language to the the Mapper.Map() function?

Currently, I am using a [ThreadStatic] attribute to set the culture before calling Mapper.Map<>, and to retrieve it in the TypeConverter.

public enum Language {     English, French, Italian, Maltese }  public class MultilingualValue<T> {     public Dictionary<Language, T> Value { get; set; }     public MultilingualValue()     {         this.Value = new Dictionary<Language, T>();     } }  public class PersonData {     public string FirstName { get; set; }     public MultilingualValue<string> City { get; set; } }  public void MapPerson() {     PersonData personData = new PersonData();     personData.FirstName = "John";     personData.City = new MultilingualValue<string>();     personData.City.Value[ Language.English] = "The Zurrieq";     personData.City.Value[Language.French] = "Le Zurrieque";      MultilingualValueData.CurrentLanguage = Language.English;       var personModel = Mapper.Map<PersonData, PersonModel>(personData); }  public class MultilingualValueToBasicDataTypeConverter<T> : ITypeConverter<MultilingualValue<T>, T>  {     public T Convert(ResolutionContext context)     {         var currentLanguage = MultilingualValueData.CurrentLanguage; //THIS IS THE [ThreadStatic] VARIABLE         if (currentLanguage == null) throw new InvalidOperationException("Please make sure to fill in CurrentLanguage");          MultilingualValue<T> sourceMultilingualValue = (MultilingualValue < T > )context.SourceValue;          T destinationValue = default(T);         if (sourceMultilingualValue != null)         {             destinationValue = sourceMultilingualValue.Value[currentLanguage.Value];         }          return destinationValue;     } }          public static class MultilingualValueData {     [ThreadStatic]     public static Language? CurrentLanguage; } 

I left out the configurations as I think they're unneccessary for this example. If you need them, I'll post them as well.

While this works, I find this workaround quite ugly. Is there any way to pass data through the ResolutionContext?

回答1:

Just use the Map overload that takes a Action<IMappingOperationOptions>. You can add configuration elements to the Items property that are then passed to your ITypeConverter

public class CustomConverter : ITypeConverter<string, string> {     public string Convert(ResolutionContext context)     {         return "translated in " + context.Options.Items["language"];     } }  internal class Program {     private static void Main(string[] args)     {         AutoMapper.Mapper.CreateMap<string, string>().ConvertUsing<CustomConverter>();         var result = AutoMapper.Mapper.Map<string, string>("value" , opt => opt.Items["language"] = "english");         Console.Write(result); // prints "translated in english"         Console.ReadLine();     } } 

文章来源: passing around values to an AutoMapper Type Converter from outside