C#•4mo ago

Json to enum deserialization issue

Can someone explain why does my controller not deserialize enum property but does for a List of that same enum in the same object?? this is the object: public class CommunityReportFilter { public List<RentalMetrics>? RentalMetrics { get; set; } public RentalMetrics? PrimaryMetric { get; set; } } This is the payload: "rentalMetrics": [ "effRent" ], "primaryMetric:": "effRent" list passes the value down but PrimaryMetric is null. Controller is configured to deserialize camelCased strings to enum

9 Replies

David Jovanovski•4mo ago

I tried changing the both to a list but only RentalMetrics deserializes still

SleepWellPupper•4mo ago

Are you using System.Text.Json? Also, your PrimaryMetric property is not of type RentalMetrics, it's of type Nullable<RentalMetrics>. Depending on your serialization engine, that might be the issue.

David Jovanovski•4mo ago

I am using System.Text.Json And the same thing happens with RentalMetrics, it just takes the first enum in the in RentalMetrics enum as default instead of taking value from primaryMetric...

SleepWellPupper•4mo ago

How is your json payload generated? Can you post your JsonSerializerOptions used?

David Jovanovski•4mo ago

C#
services.AddControllers().AddJsonOptions(options =>
{
    options.JsonSerializerOptions.Converters.Add(new JsonPropertyNameEnumConverter(JsonNamingPolicy.CamelCase));
    options.JsonSerializerOptions.Converters.Add(new DoubleConvertor());
    options.JsonSerializerOptions.Converters.Add(new FloatConvertor());
    options.JsonSerializerOptions.PropertyNameCaseInsensitive = true;
});

C#
services.AddControllers().AddJsonOptions(options =>
{
    options.JsonSerializerOptions.Converters.Add(new JsonPropertyNameEnumConverter(JsonNamingPolicy.CamelCase));
    options.JsonSerializerOptions.Converters.Add(new DoubleConvertor());
    options.JsonSerializerOptions.Converters.Add(new FloatConvertor());
    options.JsonSerializerOptions.PropertyNameCaseInsensitive = true;
});

It was done from Postman so raw json

SleepWellPupper•4mo ago

What is the JsonPropertyNameEnumConverter type? It seems to me that type is at the core of your problem, if it is responsible for (de)serializing enums... Also, try serializing the numeric enum values instead of string names, that seems to be the issue to my eyes

SleepWellPupper•4mo ago

using System;
using System.Collections.Generic;
using System.Text.Json;

var options = new JsonSerializerOptions()
{
    WriteIndented = true
};

var serialized = JsonSerializer.Serialize(new CommunityReportFilter()
{
    RentalMetrics = [RentalMetrics.FirstValue, RentalMetrics.SecondValue, RentalMetrics.DefaultValue],
    PrimaryMetric = RentalMetrics.FirstValue
}, options);
Console.WriteLine(serialized);
var deserialized = JsonSerializer.Deserialize<CommunityReportFilter>(serialized, options);

Console.WriteLine($"RentalMetrics: {String.Join(", ", deserialized.RentalMetrics ?? [])}");
Console.WriteLine($"PrimaryMetric: {deserialized.PrimaryMetric?.ToString() ?? "null"}");

public class CommunityReportFilter
{
    public List<RentalMetrics>? RentalMetrics { get; set; }
    public RentalMetrics? PrimaryMetric { get; set; }
}

public enum RentalMetrics
{
    DefaultValue,
    FirstValue,
    SecondValue
}

using System;
using System.Collections.Generic;
using System.Text.Json;

var options = new JsonSerializerOptions()
{
    WriteIndented = true
};

var serialized = JsonSerializer.Serialize(new CommunityReportFilter()
{
    RentalMetrics = [RentalMetrics.FirstValue, RentalMetrics.SecondValue, RentalMetrics.DefaultValue],
    PrimaryMetric = RentalMetrics.FirstValue
}, options);
Console.WriteLine(serialized);
var deserialized = JsonSerializer.Deserialize<CommunityReportFilter>(serialized, options);

Console.WriteLine($"RentalMetrics: {String.Join(", ", deserialized.RentalMetrics ?? [])}");
Console.WriteLine($"PrimaryMetric: {deserialized.PrimaryMetric?.ToString() ?? "null"}");

public class CommunityReportFilter
{
    public List<RentalMetrics>? RentalMetrics { get; set; }
    public RentalMetrics? PrimaryMetric { get; set; }
}

public enum RentalMetrics
{
    DefaultValue,
    FirstValue,
    SecondValue
}

yields

SleepWellPupper•4mo ago

Also, I'm noticing in your payload there are no enclosing braces. Did you leave those out or is the payload missing them? For deserializing stuff in controllers, @TeBeCo is an expert too, or so I hear...

Unknown User•4mo ago

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Json to enum deserialization issue