DifferentApproachesToGetSchema.cs

using System;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Runtime.CompilerServices;
using System.Text.Json;
using System.Threading.Tasks;

namespace JsonPlay
{
    class Program
    {
        static readonly HttpClient client = new HttpClient();
        private const string EndPoint = "https://localhost:5001/graphql?query=";

        static async Task Main(string[] args)
        {
            
            var schema = "{\r\n  __schema {\r\n    queryType {\r\n      name\r\n    }\r\n    mutationType {\r\n      name\r\n    }\r\n    subscriptionType {\r\n      name\r\n    }\r\n    types {\r\n      ...FullType\r\n    }\r\n    directives {\r\n      name\r\n      description\r\n      locations\r\n      args {\r\n        ...InputValue\r\n      }\r\n    }\r\n  }\r\n}\r\n\r\nfragment FullType on __Type {\r\n  kind\r\n  name\r\n  description\r\n  fields(includeDeprecated: true) {\r\n    name\r\n    description\r\n    args {\r\n      ...InputValue\r\n    }\r\n    type {\r\n      ...TypeRef\r\n    }\r\n    isDeprecated\r\n    deprecationReason\r\n  }\r\n  inputFields {\r\n    ...InputValue\r\n  }\r\n  interfaces {\r\n    ...TypeRef\r\n  }\r\n  enumValues(includeDeprecated: true) {\r\n    name\r\n    description\r\n    isDeprecated\r\n    deprecationReason\r\n  }\r\n  possibleTypes {\r\n    ...TypeRef\r\n  }\r\n}\r\n\r\nfragment InputValue on __InputValue {\r\n  name\r\n  description\r\n  type {\r\n    ...TypeRef\r\n  }\r\n  defaultValue\r\n}\r\n\r\nfragment TypeRef on __Type {\r\n  kind\r\n  name\r\n  ofType {\r\n    kind\r\n    name\r\n    ofType {\r\n      kind\r\n      name\r\n      ofType {\r\n        kind\r\n        name\r\n        ofType {\r\n          kind\r\n          name\r\n          ofType {\r\n            kind\r\n            name\r\n            ofType {\r\n              kind\r\n              name\r\n              ofType {\r\n                kind\r\n                name\r\n              }\r\n            }\r\n          }\r\n        }\r\n      }\r\n    }\r\n  }\r\n}";
            var typesKindName = @"{
                                      __schema {
                                        types {
                                          name kind
                                        }
                                      }
                                    }";
            var schemaQuery = @"{
                                  __schema {
                                    queryType {
                                      name kind
                                    }
                                  }
                                }";
            #region schemaQuery
            var response = await client.GetAsync($"{EndPoint + schemaQuery}");
            response.EnsureSuccessStatusCode();
            string responseBody = await response.Content.ReadAsStringAsync();
            string nameQuery = "";
            using (JsonDocument doc = JsonDocument.Parse(responseBody))
            {
                JsonElement root = doc.RootElement;
                JsonElement info = root;
                var types = info.GetProperty("data").GetProperty("__schema").GetProperty("queryType");
                nameQuery = types.GetProperty("name").GetString();
            }
            #endregion  
            #region typesKindName
            var response1 = await client.GetAsync($"{EndPoint + typesKindName}");
            response1.EnsureSuccessStatusCode();
            string responseBody1 = await response1.Content.ReadAsStringAsync();
            using (JsonDocument doc = JsonDocument.Parse(responseBody1))
            {
                JsonElement root = doc.RootElement;
                JsonElement info = root;
                var types = info.GetProperty("data").GetProperty("__schema").GetProperty("types");
                var x = types.EnumerateArray().ToArray();//because our collection is an array
                var ourTypes = x.Where(condition => condition.GetProperty("kind").GetString().Equals("OBJECT"))
                                .Where(condition => condition.GetProperty("name").GetString() == nameQuery);

                ourTypes.ToList().ForEach(res => Console.WriteLine(res));

            }
            #endregion  


            Console.ReadLine();
        }
    }
}

GetFromSchema.cs

using System;
using System.Text.Json;

namespace JsonPlay
{
    class Program
    {
        static void Main(string[] args)
        {
            var schema = "{\"_queryType\":\"GetAllQuery\",\"_mutationType\":null,\"_subscriptionType\":null,\"_directives\":[\"@include\",\"@skip\",\"@deprecated\"],\"_typeMap\":{\"String\":\"String\",\"Boolean\":\"Boolean\",\"Float\":\"Float\",\"Int\":\"Int\",\"ID\":\"ID\",\"Date\":\"Date\",\"DateTime\":\"DateTime\",\"DateTimeOffset\":\"DateTimeOffset\",\"Seconds\":\"Seconds\",\"Milliseconds\":\"Milliseconds\",\"Decimal\":\"Decimal\",\"__Schema\":\"__Schema\",\"__Type\":\"__Type\",\"__TypeKind\":\"__TypeKind\",\"__Field\":\"__Field\",\"__InputValue\":\"__InputValue\",\"__EnumValue\":\"__EnumValue\",\"__Directive\":\"__Directive\",\"__DirectiveLocation\":\"__DirectiveLocation\",\"GetAllQuery\":\"GetAllQuery\",\"DepartmentOGT\":\"DepartmentOGT\"},\"_subTypeMap\":{},\"_implementationsMap\":{}}\r\n";
          
            using (JsonDocument doc = JsonDocument.Parse(schema))
            {
                JsonElement root = doc.RootElement;
                JsonElement info = root;
                Console.WriteLine(info.GetProperty("_typeMap").GetProperty("DepartmentOGT"));
            }
            Console.ReadLine();
        }
   

MoreJsonPlay.cs

using QuickType;
using System;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Runtime.CompilerServices;
using System.Text.Json;
using System.Threading.Tasks;

namespace JsonPlay
{
    class Program
    {
        static readonly HttpClient client = new HttpClient();
        private const string EndPoint = "https://localhost:5001/graphql?query=";

        static async Task Main(string[] args)
        {
            
            var schema = "{\r\n  __schema {\r\n    queryType {\r\n      name\r\n    }\r\n    mutationType {\r\n      name\r\n    }\r\n    subscriptionType {\r\n      name\r\n    }\r\n    types {\r\n      ...FullType\r\n    }\r\n    directives {\r\n      name\r\n      description\r\n      locations\r\n      args {\r\n        ...InputValue\r\n      }\r\n    }\r\n  }\r\n}\r\n\r\nfragment FullType on __Type {\r\n  kind\r\n  name\r\n  description\r\n  fields(includeDeprecated: true) {\r\n    name\r\n    description\r\n    args {\r\n      ...InputValue\r\n    }\r\n    type {\r\n      ...TypeRef\r\n    }\r\n    isDeprecated\r\n    deprecationReason\r\n  }\r\n  inputFields {\r\n    ...InputValue\r\n  }\r\n  interfaces {\r\n    ...TypeRef\r\n  }\r\n  enumValues(includeDeprecated: true) {\r\n    name\r\n    description\r\n    isDeprecated\r\n    deprecationReason\r\n  }\r\n  possibleTypes {\r\n    ...TypeRef\r\n  }\r\n}\r\n\r\nfragment InputValue on __InputValue {\r\n  name\r\n  description\r\n  type {\r\n    ...TypeRef\r\n  }\r\n  defaultValue\r\n}\r\n\r\nfragment TypeRef on __Type {\r\n  kind\r\n  name\r\n  ofType {\r\n    kind\r\n    name\r\n    ofType {\r\n      kind\r\n      name\r\n      ofType {\r\n        kind\r\n        name\r\n        ofType {\r\n          kind\r\n          name\r\n          ofType {\r\n            kind\r\n            name\r\n            ofType {\r\n              kind\r\n              name\r\n              ofType {\r\n                kind\r\n                name\r\n              }\r\n            }\r\n          }\r\n        }\r\n      }\r\n    }\r\n  }\r\n}";
            var typesKindName = @"{
                                      __schema {
                                        types {
                                          name kind
                                        }
                                      }
                                    }";
            var schemaQuery = @"{
                                  __schema {
                                    queryType {
                                      name kind
                                    }
                                  }
                                }";
            #region schemaQuery
            var response = await client.GetAsync($"{EndPoint + schemaQuery}");
            response.EnsureSuccessStatusCode();
            string responseBody = await response.Content.ReadAsStringAsync();
            string nameQuery = "";
            using (JsonDocument doc = JsonDocument.Parse(responseBody))
            {
                JsonElement root = doc.RootElement;
                JsonElement info = root;
                var types = info.GetProperty("data").GetProperty("__schema").GetProperty("queryType");
                nameQuery = types.GetProperty("name").GetString();
            }
            #endregion  

            #region typesKindName
            var response1 = await client.GetAsync($"{EndPoint + typesKindName}");
            response1.EnsureSuccessStatusCode();
            string responseBody1 = await response1.Content.ReadAsStringAsync();
            using (JsonDocument doc = JsonDocument.Parse(responseBody1))
            {
                JsonElement root = doc.RootElement;
                JsonElement info = root;
                var types = info.GetProperty("data").GetProperty("__schema").GetProperty("types");
                var x = types.EnumerateArray().ToArray();//because our collection is an array
                var ourTypes = x.Where(condition => condition.GetProperty("kind").GetString().Equals("OBJECT"))
                                .Where(condition => condition.GetProperty("name").GetString() == nameQuery);

                //ourTypes.ToList().ForEach(res => Console.WriteLine(res));

            }
            #endregion  

            var fullResponse = await client.GetAsync($"{EndPoint + schema}");
            fullResponse.EnsureSuccessStatusCode();
            string fullResponseBody = await fullResponse.Content.ReadAsStringAsync();

            using (JsonDocument doc = JsonDocument.Parse(fullResponseBody))
            {
               // JsonElement root = doc.RootElement;
                JsonElement info = doc.RootElement;
                var allTypes = info.GetProperty("data").GetProperty("__schema").GetProperty("types").EnumerateArray()
                    .ToArray();
                var queryTypeName = info.GetProperty("data").GetProperty("__schema")
                    .GetProperty("queryType").GetProperty("name");

                var schemaObjects = allTypes
                    .Where(condition => condition.GetProperty("kind").GetString().Equals("OBJECT"))
                    .Where(condition => condition.GetProperty("name").GetString().Equals(queryTypeName.GetString()));
                var schemaObjectsToString = string.Join("", schemaObjects);

                Console.WriteLine(schemaObjectsToString);
                var obj = Root.FromJson(schemaObjectsToString);//works
                Console.WriteLine(obj.Name);
            }

            Console.ReadLine();
        }

        private static T GetJsonFromGenericType<T>(string json)
        {
            var type = JsonSerializer.Deserialize<T>(json);
            return (T)Convert.ChangeType(type, typeof(T));
        }
    }
}