CarbonFootprintCategoryGraphType.cs

public class CarbonFootprintCategoryGraphType : ObjectGraphType<ItemType>
  {
      public CarbonFootprintCategoryGraphType()
      {
          Name = "CarbonFootprintCategory";
          Field<NonNullGraphType<IntGraphType>>(
              "id",
              resolve: context => context.Source.Id
          );
          Field<NonNullGraphType<StringGraphType>>(
              "name",
              resolve: context => context.Source.Name
          );
          Field<NonNullGraphType<ListGraphType<CarbonFootprintItemGraphType>>>(
              "items",
              resolve: context => ApplicationContext.Current.DatabaseContext.GetItemsByCategoryId(context.Source.Id)
          );
      }
  }