JSON inheritance

Author: christiannagel

5_More/FilesAndStreams/JsonInheritance/JsonInheritance.csproj

@@ -0,0 +1,10 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>net7.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+</Project>

5_More/FilesAndStreams/JsonInheritance/JsonInheritance.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.6.33417.168
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "JsonInheritance", "JsonInheritance.csproj", "{791864E3-4954-441F-8DFA-DA9E04A7E7F8}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{791864E3-4954-441F-8DFA-DA9E04A7E7F8}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{791864E3-4954-441F-8DFA-DA9E04A7E7F8}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{791864E3-4954-441F-8DFA-DA9E04A7E7F8}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{791864E3-4954-441F-8DFA-DA9E04A7E7F8}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {53D3306D-D685-43EA-968A-30D87A60FE3D}
+	EndGlobalSection
+EndGlobal

5_More/FilesAndStreams/JsonInheritance/Models.cs

@@ -0,0 +1,36 @@
+using System.Text.Json.Serialization;
+
+namespace JsonInheritance;
+public record class Game(Guid GameId, string GameType, string PlayerName)
+{
+    // init modifier required for JSON deserialization
+    [JsonInclude]
+    public ICollection<Move> Moves { get; private init; } = new List<Move>();
+
+    public override string ToString() => $"""
+        {GameId}: {GameType}, {PlayerName}
+        {string.Join(':', Moves)}
+        """;
+}
+
+[JsonPolymorphic(TypeDiscriminatorPropertyName = "$discriminator")]
+[JsonDerivedType(typeof(Move<ColorField>), typeDiscriminator: "color")]
+[JsonDerivedType(typeof(Move<ShapeColorField>), typeDiscriminator: "shape")]
+public abstract record class Move(Guid GameId, Guid MoveId, int MoveNumber);
+public record class Move<TField>(Guid GameId, Guid MoveId, int MoveNumber)
+    : Move(GameId, MoveId, MoveNumber)
+{
+    public required ICollection<TField> Fields { get; init; }
+
+    public override string ToString() => string.Join(":", Fields);
+}
+
+public record class ColorField(string Color)
+{
+    public override string ToString() => $"{Color}";
+}
+
+public record class ShapeColorField(string Shape, string Color)
+{
+    public override string ToString() => $"{Shape} {Color}";
+}

5_More/FilesAndStreams/JsonInheritance/Program.cs

@@ -0,0 +1,39 @@
+using JsonInheritance;
+
+using System.Text.Json;
+
+// create the game instances
+
+Game game1 = new(Guid.NewGuid(), "6x4", "player1");
+game1.Moves.Add(new Move<ColorField>(game1.GameId, Guid.NewGuid(), 1)
+{
+    Fields = new[] { new ColorField("red"), new ColorField("blue"), new ColorField("green"), new ColorField("blue") }
+});
+
+Game game2 = new(Guid.NewGuid(), "5x5x4", "player2");
+game2.Moves.Add(new Move<ShapeColorField>(game2.GameId, Guid.NewGuid(), 1)
+{
+    Fields = new[] { new ShapeColorField("circe", "red"), new ShapeColorField("square", "blue"), new ShapeColorField("circle", "green"), new ShapeColorField("rectangle", "yellow") }
+});
+
+// serialize to JSON
+
+JsonSerializerOptions options = new()
+{
+    WriteIndented = true,
+    PropertyNamingPolicy = JsonNamingPolicy.CamelCase
+};
+
+string json1 = JsonSerializer.Serialize(game1, options);
+Console.WriteLine(json1);
+
+string json2 = JsonSerializer.Serialize(game2, options);
+Console.WriteLine(json2);
+
+// deserialize from JSON
+
+Game? game1b = JsonSerializer.Deserialize<Game>(json1, options);
+Console.WriteLine(game1b);
+
+Game? game2b = JsonSerializer.Deserialize<Game>(json2, options);
+Console.WriteLine(game2b);