有没有办法通过引用另一种类型来解决 GraphQl 类型？

Question

Im using the Graphql.Net library to build a GraphQl API. The following is a domain example of what we currently have, where, the area has a list of sampling point identifiers:

public class AreaRoot {
   public String Id { get; set; }
   public List<String > SamplingPointIds { get; set; }
}

public class SamplingPointRoot {
   public String Id { get; set; }
   public String Description { get; set; }
}

And the types are defined as follow:

public class AreaType : ObjectGraphType<AreaRoot>
{
    public AreaType()
    {
        Name = "Area";
        Field(x => x.Id, type: typeof(IdGraphType));
        Field(x => x.SamplingPointIds, type: typeof(ListGraphType<StringGraphType>));
    }
}

public class SamplingPointType : ObjectGraphType<SamplingPointRoot>
{
    public SamplingPointType()
    {
        Name = "SamplingPoint";
        Field(x => x.Id, type: typeof(IdGraphType));
        Field(x => x.description, type: typeof(StringGraphType));
    }
}

Is there any way to retrieving everything from the sampling point without changing the domain classes? there is an example in the conference GraphQL vs Traditional Rest API , in the 25:41 min, but this example is in java, and we could not make the same using the graphQl .net.

The next example illustrates the type of query we want to make:

query GetAreas(){
    areas(){
        Id
        samplingPoints{
           Id
           description
        }
    }
}

So the question is: Is there a way to this as in the video above, as we pass the samplingPoints, and resolve it, retrieving the samplingPoints for that area (in some query)?

Answer 1

Question resolved on github . For those trying to do the same, its really easy actually, we just have to had resolver inside the AreaType like this:

public class AreaType : ObjectGraphType<AreaRoot>
{
    public AreaType(IRepository repository)
    {
        Name = "Area";
        Field(x => x.Id, type: typeof(IdGraphType));
        Field<ListGraphType<SamplingPointType>>("areaSamplingPoints",
           resolve: context =>
        {
           return repository.GetAllByAreaId(context.Source?.Id);
        });
    }
}

notice the context.Source?.Id used to access the Area Id...

And also, if you are trying to access the arguments of the top level context, well, you can't, as stated here , but instead, you can access the variables passed to the query, not the best, but not the worst, so use: context.Variables.ValueFor("variableName")