5.0 updates to System.Text.Json docs

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/CopyOptions.cs

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+using System;
+using System.Text.Json;
+
+namespace CopyOptions
+{
+ public class Forecast
+ {
+ public DateTime Date { get; init; }
+ public int TemperatureC { get; set; }
+ public string Summary { get; set; }
+ };
+
+ public class Program
+ {
+ public static void Main()
+ {
+ Forecast forecast = new()
+ {
+ Date = DateTime.Now,
+ TemperatureC = 40,
+ Summary = "Hot"
+ };
+
+ JsonSerializerOptions options = new()
+ {
+ WriteIndented = true
+ };
+
+ JsonSerializerOptions optionsCopy = new(options);
+ string forecastJson = JsonSerializer.Serialize<Forecast>(forecast, optionsCopy);
+ Console.WriteLine($"Output JSON:\n{forecastJson}");
+ }
+ }
+}
+
+// Produces output like the following example:
+//
+//Output JSON:
+//{
+// "Date": "2020-10-21T15:40:06.8998502-07:00",
+// "TemperatureC": 40,
+// "Summary": "Hot"
+//}

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/CustomConverterHandleNull.cs

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+using System;
+using System.Collections.Generic;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace CustomConverterHandleNull
+{
+ public class Point
+ {
+ public int X { get; }
+ public int Y { get; }
+
+ public Dictionary<int, int> AdditionalValues;
+
+ [JsonConverter(typeof(DescriptionConverter))]
+ public string Description { get; set; }
+
+ public Point(int x, int y) => (X, Y) = (x, y);
+ }
+
+ public class DescriptionConverter : JsonConverter<string>
+ {
+ public override bool HandleNull => true;
+
+ public override string Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+ {
+ string val = reader.GetString();
+ return val ?? "No description provided.";
+ }
+
+ public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
+ {
+ writer.WriteStringValue(value);
+ }
+ }
+ public class Program
+ {
+ private static JsonSerializerOptions options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
+ {
+ IncludeFields = true,
+ WriteIndented = true
+ };
+
+ public static void Main()
+ {
+ var point = new Point(1, 2)
+ {
+ AdditionalValues = new Dictionary<int, int>
+ {
+ [3] = 4,
+ [5] = 6,
+ }
+ };
+
+ string serialized = JsonSerializer.Serialize(point, options);
+ Console.WriteLine($"Output JSON:\n{serialized}");
+
+ point = JsonSerializer.Deserialize<Point>(serialized, options);
+ Console.WriteLine($"X: {point.X}");
+ Console.WriteLine($"Y: {point.Y}");
+ Console.WriteLine($"Additional values count: {point.AdditionalValues.Count}");
+ Console.WriteLine($"AdditionalValues[3]: {point.AdditionalValues[3]}");
+ Console.WriteLine($"AdditionalValues[5]: {point.AdditionalValues[5]}");
+ Console.WriteLine($"Description: {point.Description}");
+ }
+ }
+}
+
+// Produces output like the following example:
+//
+//Output JSON:
+//{
+// "x": 1,
+// "y": 2,
+// "description": null,
+// "additionalValues": {
+// "3": 4,
+// "5": 6
+// }
+//}
+//X: 1
+//Y: 2
+//Additional values count: 2
+//AdditionalValues[3]: 4
+//AdditionalValues[5]: 6
+//Description: No description provided.

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/Fields.cs

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+using System;
+using System.Text.Json;
+
+namespace Fields
+{
+ public class Forecast
+ {
+ public DateTime Date;
+ public int TemperatureC;
+ public string Summary;
+ }
+ public class Program
+ {
+ public static void Main()
+ {
+ var json = "{\"date\":\"2020-09-06T11:31:01.923395-07:00\",\"temperatureC\":-1,\"summary\":\"Cold\"} ";
+ Console.WriteLine($"Input JSON: {json}");
+
+ var options = new JsonSerializerOptions(JsonSerializerDefaults.Web)
+ {
+ IncludeFields = true,
+ };
+ var forecast = JsonSerializer.Deserialize<Forecast>(json, options);
+
+ Console.WriteLine($"forecast.Date: {forecast.Date}");
+ Console.WriteLine($"forecast.TemperatureC: {forecast.TemperatureC}");
+ Console.WriteLine($"forecast.Summary: {forecast.Summary}");
+
+ var roundTrippedJson = JsonSerializer.Serialize<Forecast>(forecast, options);
+ Console.WriteLine($"Output JSON: {roundTrippedJson}");
+ }
+ }
+}
+
+// Produces output like the following example:
+//
+//Input JSON: { "date":"2020-09-06T11:31:01.923395-07:00","temperatureC":-1,"summary":"Cold"}
+//forecast.Date: 9/6/2020 11:31:01 AM
+//forecast.TemperatureC: -1
+//forecast.Summary: Cold
+//Output JSON: { "date":"2020-09-06T11:31:01.923395-07:00","temperatureC":-1,"summary":"Cold"}

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/GuidReferenceResolverExample.cs

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+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace GuidReferenceResolverExample
+{
+ public class Person
+ {
+ internal Guid Id { get; set; }
+ public string Name { get; set; }
+ public Person Spouse { get; set; }
+ }
+
+ public class GuidReferenceResolver : ReferenceResolver
+ {
+ private readonly IDictionary<Guid, Person> _people = new Dictionary<Guid, Person>();
+
+ public override object ResolveReference(string referenceId)
+ {
+ Guid id = new Guid(referenceId);
+
+ Person p;
+ _people.TryGetValue(id, out p);
+
+ return p;
+ }
+
+ public override string GetReference(object value, out bool alreadyExists)
+ {
+ Person p = (Person)value;
+
+ alreadyExists = _people.ContainsKey(p.Id);
+ _people[p.Id] = p;
+
+ return p.Id.ToString();
+ }
+
+ public override void AddReference(string reference, object value)
+ {
+ Guid id = new Guid(reference);
+ Person person = (Person)value;
+ person.Id = id;
+ _people[id] = person;
+ }
+ }
+
+ static class Program
+ {
+ public static void Main()
+ {
+ Person tyler = new() { Id = Guid.NewGuid(), Name = "Tyler" };
+ Person adrian = new() { Id = Guid.NewGuid(), Name = "Adrian" };
+ tyler.Spouse = adrian;
+ adrian.Spouse = tyler;
+ var people = ImmutableArray.Create(tyler, adrian);
+
+ var options = new JsonSerializerOptions
+ {
+ WriteIndented = true,
+ ReferenceHandler = new ReferenceHandler<GuidReferenceResolver>()
+ };
+
+ string json = JsonSerializer.Serialize(people, options);
+ Console.WriteLine($"Output JSON {json}");
+
+ List<Person> peopleDeserialized = JsonSerializer.Deserialize<List<Person>>(json, options);
+
+ Person tylerDeserialized = people[0];
+ Person adrianDeserialized = people[1];
+
+ Console.WriteLine($"Adrian is Tyler's spouse: {tylerDeserialized.Equals(adrianDeserialized.Spouse)}");
+ Console.WriteLine($"Tyler is Adrian's spouse: {adrianDeserialized.Equals(tylerDeserialized.Spouse)}");
+ }
+ }
+}
+
+// Produces output like the following example:
+//
+//Output JSON[
+// {
+// "$id": "79301726-9d94-499a-8cdc-0c8bcc4c9b63",
+// "Name": "Tyler",
+// "Spouse": {
+// "$id": "94833059-35f2-4fdd-96ee-94fd0484969a",
+// "Name": "Adrian",
+// "Spouse": {
+// "$ref": "79301726-9d94-499a-8cdc-0c8bcc4c9b63"
+// }
+// }
+// },
+// {
+// "$ref": "94833059-35f2-4fdd-96ee-94fd0484969a"
+// }
+//]
+//Adrian is Tyler's spouse: True
+//Tyler is Adrian's spouse: True

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/HttpClientExtensionMethods.cs

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+using System;
+using System.Net.Http;
+using System.Net.Http.Json;
+using System.Threading.Tasks;
+
+namespace HttpClientExtensionMethods
+{
+ public class User
+ {
+ public int Id { get; set; }
+ public string Name { get; set; }
+ public string Username { get; set; }
+ public string Email { get; set; }
+ }
+ public class Program
+ {
+ public static async Task Main()
+ {
+ var client = new HttpClient();
+ client.BaseAddress = new Uri("https://jsonplaceholder.typicode.com");
+
+ // Get the user information.
+ User user = await client.GetFromJsonAsync<User>("users/1");
+ Console.WriteLine($"Id: {user.Id}");
+ Console.WriteLine($"Name: {user.Name}");
+ Console.WriteLine($"Username: {user.Username}");
+ Console.WriteLine($"Email: {user.Email}");
+
+ // Post a new user.
+ HttpResponseMessage response = await client.PostAsJsonAsync("users", user);
+ Console.WriteLine((response.IsSuccessStatusCode ? "Success" : "Error") + $" - {response.StatusCode}");
+ }
+ }
+}
+
+// Produces output like the following example but with different names:
+//
+//Id: 1
+//Name: Tyler King
+//Username: Tyler
+//Email: Tyler @contoso.com
+//Success - Created

docs/standard/serialization/snippets/system-text-json-how-to-5-0/csharp/IgnoreValueDefaultOnSerialize.cs

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+#nullable enable
+using System;
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace IgnoreValueDefaultOnSerialize
+{
+ public class Forecast
+ {
+ public DateTime Date { get; set; }
+ public int TemperatureC { get; set; }
+ public string? Summary { get; set; }
+ };
+
+ public class Program
+ {
+ public static void Main()
+ {
+ Forecast forecast = new()
+ {
+ Date = DateTime.Now,
+ Summary = null,
+ TemperatureC = default(int)
+ };
+
+ JsonSerializerOptions options = new()
+ {
+ DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingDefault
+ };
+
+ string forecastJson = JsonSerializer.Serialize<Forecast>(forecast, options);
+ Console.WriteLine(forecastJson);
+ }
+ }
+}
+
+// Produces output like the following example:
+//
+//{ "Date":"2020-10-21T15:40:06.8920138-07:00"}