【WebAPI】返回JSON数据_webapi返回json数据

在Global.asax文件WebApiApplication中配置

public class WebApiApplication : System.Web.HttpApplication
{
    protected void Application_Start()
    {
        AreaRegistration.RegisterAllAreas();
        GlobalConfiguration.Configure(WebApiConfig.Register);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);
        BundleConfig.RegisterBundles(BundleTable.Bundles);
        //返回json数据
        GlobalConfiguration.Configuration.Formatters.XmlFormatter.SupportedMediaTypes.Clear();
    }
}

或

在WebApiConfig中配置

public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API 配置和服务
            config.Services.Replace(typeof(IContentNegotiator), new JsonContentNegotiator(new JsonMediaTypeFormatter()));
 
            // Web API 路由
            config.MapHttpAttributeRoutes();
 
            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }
 
        /// <summary>
        ///  在全局设置中，使用自定义的只返回Json Result。只让api接口中替换xml，返回json。这种方法的性能是最高的！
        /// </summary>
        public class JsonContentNegotiator : IContentNegotiator
        {
            private readonly JsonMediaTypeFormatter _jsonFormatter;
            public JsonContentNegotiator(JsonMediaTypeFormatter formatter)
            {
                _jsonFormatter = formatter;
            }
            public ContentNegotiationResult Negotiate(Type type, HttpRequestMessage request, IEnumerable<MediaTypeFormatter> formatters)
            {
                // 对 JSON 数据使用混合大小写。驼峰式,但是是javascript 首字母小写形式.小驼峰命名法。
                //config.Formatters.JsonFormatter.SerializerSettings.ContractResolver = new  CamelCasePropertyNamesContractResolver();
                // 对 JSON 数据使用混合大小写。跟属性名同样的大小.输出
                _jsonFormatter.SerializerSettings.ContractResolver = new UnderlineSplitContractResolver(); //小写命名法。
                _jsonFormatter.SerializerSettings.DateFormatString = "yyyy-MM-dd HH:mm:ss";//解决json时间带T的问题
                _jsonFormatter.SerializerSettings.Formatting = Newtonsoft.Json.Formatting.Indented;//解决json格式化缩进问题
                _jsonFormatter.SerializerSettings.ReferenceLoopHandling = Newtonsoft.Json.ReferenceLoopHandling.Ignore;//解决json序列化时的循环引用问题
                var result = new ContentNegotiationResult(_jsonFormatter, new MediaTypeHeaderValue("application/json"));
                return result;
            }
        }
 
        /// <summary>
        /// Json.NET 利用ContractResolver解决命名不一致问题
        /// 解决问题：通过无论是序列化还是反序列化都达到了效果，即：ProjectName -> project_name 和 project_name -> ProjectName
        /// </summary>
        public class UnderlineSplitContractResolver : DefaultContractResolver
        {
            protected override string ResolvePropertyName(string propertyName)
            {
                return CamelCaseToUnderlineSplit(propertyName);//下划线分割命名法
                                                               //return propertyName.ToLower();//小写命名法
            }
 
            private string CamelCaseToUnderlineSplit(string name)
            {
                StringBuilder builder = new StringBuilder();
                for (int i = 0; i < name.Length; i++)
                {
                    var ch = name[i];
                    if (char.IsUpper(ch) && i > 0)
                    {
                        var prev = name[i - 1];
                        if (prev != '_')
                        {
                            if (char.IsUpper(prev))
                            {
                                if (i < name.Length - 1)
                                {
                                    var next = name[i + 1];
                                    if (char.IsLower(next))
                                    {
                                        builder.Append('_');
                                    }
                                }
                            }
                            else
                            {
                                builder.Append('_');
                            }
                        }
                    }
 
                    builder.Append(char.ToLower(ch));
                }
 
                return builder.ToString();
            }
 
 
        }
    }

参考：

https://www.cnblogs.com/xinyibufang/p/10478137.html