aspnetcore 取消默认Json首字母小写

        public void ConfigureServices(IServiceCollection services)
        {
            // 根据类是否添加注解[IsService]来自动注入
            var assm = new[] { typeof(Program).Assembly, typeof(DbCtxt).Assembly };
            foreach (var ass in assm)
            {
                var types = ass.GetTypes();
                foreach (var typ in types)
                {
                    var typeInfo = typ.GetTypeInfo();
                    if (typeInfo.IsDefined(typeof(IsServiceAttribute)))
                    {
                        services.AddScoped(typ);
                        var interfaces = typeInfo.ImplementedInterfaces;
                        foreach (var item in interfaces)
                        {
                            services.AddScoped(item, typ);
                        }
                    }
                }
            }

            services.AddControllers();

            services.AddMvc(op => op.Filters.Add(typeof(TransActionFilter)))
            .AddJsonOptions(op =>
            {
                op.JsonSerializerOptions.PropertyNameCaseInsensitive = true;
                op.JsonSerializerOptions.PropertyNamingPolicy = null;// 取消默认首字母小写
            });
        }