{"id":67044,"date":"2022-03-15T07:31:27","date_gmt":"2022-03-15T06:31:27","guid":{"rendered":"https:\/\/drafts.code-maze.com\/?p=67044"},"modified":"2022-06-09T09:20:08","modified_gmt":"2022-06-09T07:20:08","slug":"csharp-serialize-enum-to-string","status":"publish","type":"post","link":"https:\/\/code-maze.com\/csharp-serialize-enum-to-string\/","title":{"rendered":"How to Serialize Enum to a String in C#"},"content":{"rendered":"

In this article, we are going to learn how to serialize enum to a string in C#.<\/p>\n

To download the source code for this article, you can visit our GitHub repository<\/a>.<\/div>\n

In C#, JSON serialization very often needs to deal with enum<\/code> objects. By default,<\/strong> enums<\/code> are serialized in their integer form. This often causes a lack of interoperability with consumer applications because they need prior knowledge of what those numbers actually mean.<\/strong> So, we want them to serialize as strings in many instances. We are going to see various ways to do this using the native System.Text.Json<\/code> library and\u00a0the popular Newtonsoft.Json<\/code> library. It is a general-purpose solution for most parts.\u00a0<\/p>\n

Default Way to Serialize Enum to String in C#<\/h2>\n

To begin, let’s prepare a few object models:<\/p>\n

public class Canvas\r\n{\r\n    public static Canvas Poster \r\n        => new() { Name = \"Poster\", BackColor = Color.LightGray, Pen = new (\"Simple\", Color.Red) };\r\n\r\n    public string? Name { get; set; }\r\n\r\n    public Color BackColor { get; set; }\r\n\r\n    public Medium Medium { get; set; }\r\n\r\n    public Pen? Pen { get; set; }\r\n}\r\n\r\npublic record struct Pen(string Name, Color Color);\r\n\r\npublic enum Color\r\n{\r\n    White, LightGray, DarkGray, Red\r\n}\r\n\r\npublic enum Medium\r\n{\r\n    Water, Oil\r\n}<\/pre>\n
We declare two enums: Color<\/code> and Medium<\/code>, a record Pen<\/code>, and a class Canvas<\/code>. Canvas<\/code> is our primary model in concern. Also, we declare a static Canvas<\/code> instance (Poster<\/code>) for convenient use in examples.<\/p>\n
Next, we are going to add a basic Serialize<\/code> method in the base class (UnitTestBase<\/code>):<\/p>\n
\/\/ Native\r\npublic static string Serialize(object obj)\r\n{\r\n    return JsonSerializer.Serialize(obj);\r\n}\r\n\r\n\/\/ Newtonsoft\r\npublic static string Serialize(object obj)\r\n{\r\n    return JsonConvert.SerializeObject(obj);\r\n}<\/pre>\n
All set, we’re ready to go.<\/p>\n
First, let’s check the default behavior of serialization on Canvas.Poster<\/code> object:<\/p>\n
var json = Serialize(Canvas.Poster);<\/code><\/p>\n
And let’s inspect the result:<\/p>\n
{\r\n  \"Name\": \"Poster\",\r\n  \"BackColor\": 1,\r\n  \"Medium\": 0,\r\n  \"Pen\": {\r\n    \"Name\": \"Simple\",\r\n    \"Color\": 3\r\n  }\r\n}<\/pre>\n
No wonder, the resulting string contains the enum properties (BackColor<\/code>, Medium<\/code>, Pen.Color<\/code>) as integer values.<\/p>\n
So, the question arises: “Can enum be serialized to a string in C#”? Let’s look for the answer in the rest of the article.<\/p>\n
Different Ways to Serialize Enum to String in C#<\/h2>\n
We want to serialize the enums as strings. Both native and Newtonsoft libraries provide a converter for this purpose, named as JsonStringEnumConverter<\/strong> and StringEnumConverter<\/strong> respectively. They also provide an attribute JsonConverterAttribute<\/strong> that we can use to serialize string-enum selectively.<\/p>\n
Serialization of an Enum Property<\/h3>\n
First of all, we want to serialize the BackColor<\/code> property as a string. So, it’s time to change the Canvas<\/code> model and decorate the BackColor<\/code> property with the converter attribute:<\/p>\n
\/\/ Native\r\npublic class Canvas\r\n{\r\n    ...\r\n    [JsonConverter(typeof(JsonStringEnumConverter))]\r\n    public Color BackColor { get; set; }\r\n    ...\r\n}\r\n\r\n\/\/ Newtonsoft\r\npublic class Canvas\r\n{\r\n    ...\r\n    [JsonConverter(typeof(StringEnumConverter))]\r\n    public Color BackColor { get; set; }\r\n    ...\r\n}<\/pre>\n
Now the serialization of Canvas.Poster<\/code> :<\/p>\n
var json = Serialize(Canvas.Poster);<\/code><\/p>\n
Produces a different output:<\/p>\n
{\r\n  \"Name\": \"Poster\",\r\n  \"BackColor\": \"LightGray\",\r\n  \"Medium\": 0,\r\n  \"Pen\": {\r\n    \"Name\": \"Simple\",\r\n    \"Color\": 3\r\n  }\r\n}<\/pre>\n
We can see that BackColor<\/code> turns to string but Medium<\/code> and Pen.Color<\/code> don’t, because they don’t have the converter attribute applied. This means we can selectively serialize specific enum<\/code> properties in this way.<\/p>\n
Serialization of an Enum Type<\/h3>\n
Next, we want to serialize all instances of the Color<\/code> enum to strings. We can do this by applying the converter attribute on the enumeration type itself instead of the properties:<\/p>\n
public class Canvas\r\n{\r\n    ...\r\n    public Color BackColor { get; set; }\r\n    ...\r\n}\r\n\r\n\/\/ Native\r\n[JsonConverter(typeof(JsonStringEnumConverter))]\r\npublic enum Color\r\n{\r\n    White,\u00a0LightGray,\u00a0DarkGray,\u00a0Red\r\n}\r\n\r\n\/\/ Newtonsoft\r\n[JsonConverter(typeof(StringEnumConverter))]\r\npublic enum Color\r\n{\r\n    White, LightGray, DarkGray, Red\r\n}<\/pre>\n
Again, after the serialization, the end result differs from the previous one:<\/p>\n
{\r\n  \"Name\": \"Poster\",\r\n  \"BackColor\": \"LightGray\",\r\n  \"Medium\": 0,\r\n  \"Pen\": {\r\n    \"Name\": \"Simple\",\r\n    \"Color\": \"Red\"\r\n  }\r\n}<\/pre>\n
This time we can see all Color<\/code> instances (BackColor<\/code> and Pen.Color<\/code>) turn to string, but Medium<\/code> enum still follows the default behavior. So in this way, we can selectively serialize some specific enum types to string.<\/p>\n
Inline JSON Serialization of Enum to String<\/h2>\n
We can’t go with the attribute-based approaches in some cases such as:<\/p>\n