In ASP.NET Core 3.0 Web API project, how do you specify System.Text.Json serialization options to serialize/deserialize Pascal Case properties to Camel Case and vice versa automatically?
Given a model with Pascal Case properties such as:
public class Person { public string Firstname { get; set; } public string Lastname { get; set; } }
And code to use System.Text.Json to deserialize a JSON string to type of Person
class:
var json = "{\"firstname\":\"John\",\"lastname\":\"Smith\"}"; var person = JsonSerializer.Deserialize<Person>(json);
Does not successfully deserialize unless JsonPropertyName is used with each property like:
public class Person { [JsonPropertyName("firstname")] public string Firstname { get; set; } [JsonPropertyName("lastname")] public string Lastname { get; set; } }
I tried the following in startup.cs
, but it did not help in terms of still needing JsonPropertyName
:
services.AddMvc().AddJsonOptions(options => { options.JsonSerializerOptions.DictionaryKeyPolicy = JsonNamingPolicy.CamelCase; options.JsonSerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase; }); // also the following given it's a Web API project services.AddControllers().AddJsonOptions(options => { options.JsonSerializerOptions.DictionaryKeyPolicy = JsonNamingPolicy.CamelCase; options.JsonSerializerOptions.PropertyNamingPolicy = JsonNamingPolicy.CamelCase; });
How can you set Camel Case serialize/deserialize in ASP.NET Core 3.0 using the new System.Text.Json namespace?
Thanks!
Json does case-insensitive property name matching by default. The System. Text. Json default is case-sensitive, which gives better performance since it's doing an exact match.
A common way to deserialize JSON is to first create a class with properties and fields that represent one or more of the JSON properties. Then, to deserialize from a string or a file, call the JsonSerializer. Deserialize method.
JsonPropertyAttribute indicates that a property should be serialized when member serialization is set to opt-in. It includes non-public properties in serialization and deserialization. It can be used to customize type name, reference, null, and default value handling for the property value.
AddJsonOptions()
would config System.Text.Json
only for MVC. If you want to use JsonSerializer
in your own code you should pass the config to it.
var options = new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.CamelCase, }; var json = "{\"firstname\":\"John\",\"lastname\":\"Smith\"}"; var person = JsonSerializer.Parse<Person>(json, options);
In startup.cs
:
// keeps the casing to that of the model when serializing to json // (default is converting to camelCase) services.AddMvc() .AddJsonOptions(options => options.JsonSerializerOptions.PropertyNamingPolicy = null);
This means you don't need to import newtonsoft.json.
The only other option for options.JsonSerializerOptions.PropertyNamingPolicy
is JsonNamingPolicy.CamelCase
. There do not seem to be any other JsonNamingPolicy
naming policy options, such as snake_case or PascalCase.
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