[转]C#进阶系列——WebApi 接口返回值不困惑：返回值类型详解

阅读目录

• 一、void无返回值
• 二、IHttpActionResult
  • 1、Json(T content)
  • 2、Ok()、 Ok(T content)
  • 3、NotFound()
  • 4、其他
  • 5、自定义IHttpActionResult接口的实现
• 三、HttpResponseMessage
• 四、自定义类型
• 五、总结 

　　 public class ORDER
    {
        public string ID { get; set; }

        public string NO { get; set; }

        public string NAME { get; set; }

        public string DESC { get; set; }
    }

　　 public class OrderController : ApiController
    {
        [HttpPost]
        public void SaveOrder(ORDER name)
        { 
            //处理业务逻辑

        }
    }

$(function () {
    $.ajax({
        type: 'post',
        url: 'http://localhost:21528/api/Order/SaveOrder',
        data: { ID: "aaa", NAME: "test" },
        success: function (data, status) {
            alert(data);
        }
    });
});

　　　　 public JsonResult GetResult()
        {
            return Json(new { }, JsonRequestBehavior.AllowGet);
        }

　　　　 [HttpGet]
        public IHttpActionResult GetOrder()
        {
            var lstRes = new List<ORDER>(); 

            //实际项目中，通过后台取到集合赋值给lstRes变量。这里只是测试。
            lstRes.Add(new ORDER() { ID = "aaaa", NO = "111", NAME = "111", DESC = "1111" });
            lstRes.Add(new ORDER() { ID = "bbbb", NO = "222", NAME = "222", DESC = "2222" });

            return Json<List<ORDER>>(lstRes);
        }

        protected internal JsonResult<T> Json<T>(T content); 

$(function () {
    $.ajax({
        type: 'get',
        url: 'http://localhost:21528/api/Order/GetOrder',
        data: {},
        success: function (data, status) {
            alert(data);
        }
    });
});

        [HttpGet]
        public IHttpActionResult GetOrder()
        {
          
            return Json<dynamic>(new { AA = "", BB = "cc" });
        }

protected internal virtual OkResult Ok();

        [HttpGet]
        public IHttpActionResult GetOKResult()
        {
            return Ok();
        }

        [HttpGet]
        public IHttpActionResult GetOKResult(string name)
        {
            return Ok<string>(name);
        }

protected internal virtual NotFoundResult NotFound();

        [HttpGet]
        public IHttpActionResult GetNotFoundResult(string id)
        {
            var lstRes = new List<ORDER>();

            //实际项目中，通过后台取到集合赋值给lstRes变量。这里只是测试。
            lstRes.Add(new ORDER() { ID = "aaaa", NO = "111", NAME = "111", DESC = "1111" });
            lstRes.Add(new ORDER() { ID = "bbbb", NO = "222", NAME = "222", DESC = "2222" });
            var oFind = lstRes.FirstOrDefault(x => x.ID == id) ;
            if (oFind == null)
            {
                return NotFound();
            }
            else
            {
                return Json<ORDER>(oFind);
            }
        }

$(function () {
    $.ajax({
        type: 'get',
        url: 'http://localhost:21528/api/Order/GetNotFoundResult',
        data: { id :"cccc" },
        success: function (data, status) {
            alert(data);
        }
    });
});

        [HttpGet]
        public IHttpActionResult GetContentResult()
        {
            return Content<string>(HttpStatusCode.OK, "OK");
        }

        [HttpGet]
        public IHttpActionResult GetBadRequest(ORDER order)
        {
            if (string.IsNullOrEmpty(order.ID))
                return BadRequest();
            return Ok();
        }

        [HttpGet]
        public IHttpActionResult RedirectResult()
        {
            return Redirect("http://localhost:21528/api/Order/GetContentResult");
        }

namespace System.Web.Http
{
    // 摘要: 
    //     Defines a command that asynchronously creates an System.Net.Http.HttpResponseMessage.
    public interface IHttpActionResult
    {
        // 摘要: 
        //     Creates an System.Net.Http.HttpResponseMessage asynchronously.
        //
        // 参数: 
        //   cancellationToken:
        //     The token to monitor for cancellation requests.
        //
        // 返回结果: 
        //     A task that, when completed, contains the System.Net.Http.HttpResponseMessage.
        Task<System.Net.Http.HttpResponseMessage> ExecuteAsync(CancellationToken cancellationToken);
    }
}

 　　public class PageResult : IHttpActionResult
    {
        object _value;
        HttpRequestMessage _request;

        public PageResult(object value, HttpRequestMessage request)
        {
            _value = value;
            _request = request;
        }

        public Task<HttpResponseMessage> ExecuteAsync(System.Threading.CancellationToken cancellationToken)
        {
            var response = new HttpResponseMessage()
            {
                Content = new ObjectContent(typeof(object), _value, new JsonMediaTypeFormatter()),
                RequestMessage = _request
            };
            return Task.FromResult(response);
        }
    }

 　　　　[HttpGet]
        public IHttpActionResult GetPageRow(int limit, int offset)
        {
            var lstRes = new List<ORDER>();

            //实际项目中，通过后台取到集合赋值给lstRes变量。这里只是测试。
            lstRes.Add(new ORDER() { ID = "aaaa", NO = "111", NAME = "111", DESC = "1111" });
            lstRes.Add(new ORDER() { ID = "bbbb", NO = "222", NAME = "222", DESC = "2222" });

            var oData = new { total = lstRes.Count, rows = lstRes.Skip(offset).Take(limit).ToList() };
            return new PageResult(oData, Request);
        }

$(function () {
    $.ajax({
        type: 'get',
        url: 'http://localhost:21528/api/Order/GetPageRow',
        data: { limit:1,offset:1},
        success: function (data, status) {
            alert(data);
        }
    });
});

　　　　public HttpResponseMessage Export()
        {
            //取数据
            var lstRes = OrderBLL.Export();

            //向Excel里面填充数据
            HSSFWorkbook workbook = new HSSFWorkbook();
            CreateAndFillSheet(workbook, lstRes);
            
            //保存到服务
            var fileName = "Excel" + DateTime.Now.ToString("yyyyMMddHHmmss") + ".xls";
            var strPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, @"Data" + fileName);
            using (FileStream fs = new FileStream(strPath, FileMode.Create))
            {
                workbook.Write(fs);
                using (MemoryStream ms = new MemoryStream())
                {
                    workbook.Write(ms);
                }
            }

            //输出到浏览器
            try
            {
                var stream = new FileStream(strPath, FileMode.Open);
                HttpResponseMessage response = new HttpResponseMessage(HttpStatusCode.OK);
                response.Content = new StreamContent(stream);
                response.Content.Headers.ContentType = new MediaTypeHeaderValue("application/octet-stream");
                response.Content.Headers.ContentDisposition = new ContentDispositionHeaderValue("attachment")
                {
                    FileName = fileName
                };

                return response;
            }
            catch
            {
                return new HttpResponseMessage(HttpStatusCode.NoContent);
            }
        }

        [HttpGet]
        public object GetOther()
        {
            var lstRes = new List<ORDER>();

            //实际项目中，通过后台取到集合赋值给lstRes变量。这里只是测试。
            lstRes.Add(new ORDER() { ID = "aaaa", NO = "111", NAME = "111", DESC = "1111" });
            lstRes.Add(new ORDER() { ID = "bbbb", NO = "222", NAME = "222", DESC = "2222" });

            return lstRes;
        }