Preserve JSON case using NewtonSoft in aspnet core 3.x

README.md

With aspnet core 3.x, the default Text JSON serializer as well as the Newtonsoft extension (if you're still holding on to Newtonsoft like I am) apply a camel casing naming strategy.

This means that for your upper case properties in C# land, they get translated to lower case starting letters in javascript. This is great. Unless you're dealing with a legacy codebase where the javascript is expecting the starting upper cases.

The fix is easy. Just set contract resolver in your Startup to an instance of DefaultContractResolver.

Startup.cs

using json.Middleware;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Newtonsoft.Json;
using Newtonsoft.Json.Serialization;

namespace json
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            var resolver =

            services.AddControllersWithViews()
            .AddNewtonsoftJson(opts =>
                {
                    opts.SerializerSettings.ContractResolver =  new DefaultContractResolver();
                });
        }
        

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }
}

Oh, nice catch. Yes, that does work