GraphQLQuery.cs

public class GraphQLQuery : ObjectGraphType
{
    public GraphQLQuery(IServiceProvider serviceProvider)
    {
        var type = typeof(IResolver);
        var resolversTypes = AppDomain.CurrentDomain.GetAssemblies()
            .SelectMany(s => s.GetTypes())
            .Where(p => type.IsAssignableFrom(p));

        foreach(var resolverType in resolversTypes)
        {
            var resolverTypeInterface = resolverType.GetInterfaces().Where(x => x != type).FirstOrDefault();
            if(resolverTypeInterface != null)
            {
                var resolver = serviceProvider.GetService(resolverTypeInterface) as IResolver;
                resolver.Resolve(this);
            }
        }
    }
}