I have following code inside Startup.cs and expecting it to override default serialization options. I want it to override every single serialization throughout my asp net co
In ASP.NET Core, this is configured when wiring up the services on the application in Startup.ConfigureServices. There is an fluent AddJsonOptions(Action<MvcJsonOptions>) extension to the IMvcBuilder returned by the AddMvc() extension. MvcJsonOptions exposes a SerializerSettings property which you can configure in your action code.
So instead of configuring once before registering MVC, it's done as part of the MVC registration.
Example incorporating your setup:
services.AddMvc()
.AddJsonOptions( options =>
{
options.SerializerSettings.Formatting = Formatting.Indented;
options.SerializerSettings.TypeNameHandling = TypeNameHandling.Objects;
options.SerializerSettings.ContractResolver = new CamelCasePropertyNamesContractResolver();
options.SerializerSettings.Converters.Add(new StringEnumConverter());
});