31

I have come across a piece of code in my Web API project, which has a class of this structure:

public class QuestionDto
{
    public bool disabled {get;set;}
    public int id {get;set;}
    public int order {get;set;}
    public PositionDto pagePosition {get;set;}
    public string title {get;set;}
}

public enum PositionDto
{
    FullWidth = 0,
    Half = 1
}

There is an API call that returns QuestionDto, along the lines of:

[Route("")]
[HttpGet]
[ResponseType(typeof(QuestionDto))]
public async Task<IHttpActionResult> GetCategoryQuestions()
{
    return Ok(new QuestionDto { PagePosition = PagePositionDto.Half });
}

Here is a snip from the Chrome console network tab showing the repsonse for this API call:

enter image description here

How can the enum be returning its text value, rather than its int value?

To confuse this even further, if I then take this same class structure and copy and paste to a differrent project, the api call returning this object will return the int value - which is what I would expect.

So how can the first project be returning the string value?

Is there some setting somewhere which can make this enum return its string value?

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0

6 Answers 6

Reset to default
48

There is a setting that can be added to a variable, that will return the string value in JSON.

It can either be set on the variable declaration like this:

[JsonConverter(typeof(StringEnumConverter))]
public PositionDto pagePosition { get; set; }

or it can be set globally, like this:

var json = config.Formatters.JsonFormatter;
json.SerializerSettings.Converters.Add(new StringEnumConverter());
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3 Comments

@Alex First line of second code block, var json = config. ...
@LWChris Typically you will need to this line of code in .NET 4.x in your 'WebApiConfig.cs' file within the App_Start folder. This contains a Register method passing in a HttpConfiguration object (config), where you setup stuff like http filters, route configuration, formatters etcetera
In System.Text.Json.Serialization you can use [JsonConverter(typeof(JsonStringEnumConverter))]
25

If you are using asp.net core or dotnet 6, use JsonStringEnumConverter instead of StringEnumConverter [JsonConverter(typeof(JsonStringEnumConverter))]

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Comments

18

For WebAPI with .Net 5.0 you can do this in ConfigureServices in Startup.cs for global solution to enums:

services.AddControllers().AddJsonOptions(options =>
{
    options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());
    options.JsonSerializerOptions.IgnoreNullValues = true;
});
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12

For .NET Core 6, use the following code in the Program.cs

builder.Services.AddControllers().AddJsonOptions(options =>
{
   options.JsonSerializerOptions.Converters.Add(new JsonStringEnumConverter());

   options.JsonSerializerOptions.DefaultIgnoreCondition =
       JsonIgnoreCondition.WhenWritingNull;
});
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1 Comment

This is actually a good way of doing it throughout the whole project, not just endpoint specific. And is a modern approach
2

Alex has the right answer - just to add a little - if you're using Newtonsoft.Json you'll need to include "using Newtonsoft.Json.Converters;" to have StringEnumConverter available.

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-3 
return Ok(new QuestionDto { PagePosition.Value = PagePositionDto.Half.Value });
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1 Comment

Please elaborate how your code solves the issue.

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