AutoMapper IValueResolver throws error The type cannot be used as type parameter 'TValueResolver' in the generic type or method

Question

I tried to implement IValueResolver interface in the new version of AutoMapper. I have implemented ResourceTypeResolver class as follows..

public interface IValueResolver<in TSource, in TDestination, TDestMember>
{
    TDestMember Resolve(TSource source, TDestination destination, TDestMember destMember, ResolutionContext context);
}

public class ResourceTypeResolver : IValueResolver<PMEasy.Model.Entity.Resource, PMEasy.Web.Models.Gantt.GanttResource, string>
{
    private ILookupService LookupService;
    public ResourceTypeResolver(ILookupService lookupService)
    {
        LookupService = lookupService;
    }
    public string Resolve(PMEasy.Model.Entity.Resource source, PMEasy.Web.Models.Gantt.GanttResource destination, string member, ResolutionContext context)
    {
        if (source.Type.HasValue && source.Type != Guid.Empty)
        {
            var resourceType = LookupService.GetLookupListByName("ResourceType").Where(con => con.GUID == source.Type.Value).FirstOrDefault();
            return resourceType != null ? resourceType.Value : string.Empty;
        }
        else return "Work";
    }
}

After I used this ResourceTypeResolver inside Mapper Configuration

var config = new MapperConfiguration(cfg =>
        {
        cfg.CreateMap<Resource, GanttResource>()
               .ForMember(dst => dst.TypeName, opt => opt.ResolveUsing<ResourceTypeResolver>()));
        } 

Here I m getting an error in ResolveUsing context ,

Error 19 The type 'PMEasy.Web.AutoMapper.ResourceTypeResolver' cannot be used as type parameter 'TValueResolver' in the generic type or method 'AutoMapper.IMemberConfigurationExpression.ResolveUsing()'. There is no implicit reference conversion from 'PMEasy.Web.AutoMapper.ResourceTypeResolver' to 'AutoMapper.IValueResolver'. D:\PMEasy\Development\PMEasyDev\PMEasy.Web\App_Start\AutoMapperConfig.cs 58 59 PMEasy.Web

Any ideas how can we fixed this issue ?

Answer 1

It seems, that you create your own interface IValueResolver<in TSource, in TDestination, TDestMember>, intsead of using automapper's one. Soo, remove your interface definition.