I am trying to create a custom resolver for my AutoMapper that is close to identical to the source documentation for custom resolvers from the AutoMapper team. I have the IValueResolver implementation called NluProgressResolver

public class NluProgressResolver : IValueResolver<CluTrainingJobStateModel, NluTrainingStateDto, object>
{
    public object Resolve(CluTrainingJobStateModel source, NluTrainingStateDto dest, object member, ResolutionContext context)
        => new NluTrainingProgress()
        { 
            Percentage = (source.Result.EvaluationStatus!.PercentComplete + source.Result.TrainingStatus!.PercentComplete) / 2
        };
}

Which takes it’s source from CluTrainingJobStateModel and it’s destination is NluTrainingStateDto

public class CluTrainingJobStateModel
{
    [JsonPropertyName("result")]
    public required CluTrainingJobStateResult Result { get; set; }
    [JsonPropertyName("jobId")]
    public required string JobId { get; set; }
    [JsonPropertyName("createdDateTime")]
    public string? CreatedDateTime { get; set; }
    [JsonPropertyName("lastUpdatedDateTime")]
    public string? LastUpdatedDateTime { get; set; }
    [JsonPropertyName("expirationDateTime")]
    public string? ExpirationDateTime { get; set; }
    [JsonPropertyName("status")]
    public CluTrainingJobStatus? Status { get; set; }
}

public class NluTrainingStateDto
{
    [JsonPropertyName("id")]
    public required string Id { get; set; }
    [JsonPropertyName("status")]
    public NluTrainingStatus? Status { get; set; }
    [JsonPropertyName("progress")]
    public NluTrainingProgress? Progress { get; set; }
}

Which I then try to use inside a CreateMap as follows:

CreateMap<CluTrainingJobStateModel, NluTrainingStateDto>()
    .ForMember(dest => dest.Id, opt => opt.MapFrom(src => src.JobId))
    .ForMember(dest => dest.Status, opt => opt.MapFrom(src => src.Status))
    .ForMember(dest => dest.Progress, opt => opt.MapFrom<NluProgressResolver>());

This results in an error on the NluProgressResolver as shown below ->

The type ‘Namespace.NluProgressResolver’ cannot be used as type parameter ‘TValueResolver’ in the generic type or method ‘IMemberConfigurationExpression<CluTrainingJobStateModel, NluTrainingStateDto, NluTrainingProgress?>.MapFrom()’. There is no implicit reference conversion from ‘Namespace.NluProgressResolver’ to ‘AutoMapper.IValueResolver<Namespace.CluTrainingJobStateModel, Namespace.NluTrainingStateDto, Namespace.NluTrainingProgress?>’. (I shortened the actual namespace to `Namespace for to make it easier to read)

I also want to add that I replaced NluTrainingProgress with object in the resolver, but it shows the exact same error but instead referring to object where it says Namespace.NluTrainingProgress?

P.S. I am aware that this is probably not following some best practices, so any tips are welcomed.