MVC入门之Controllers

下面是一个Controller的定义：

    public class ProductController : Controller
    {
        //
        // GET: /Product/

        public ActionResult Index()
        {
            return View();
        }

        public ActionResult Help()
        {
            return View();
        }

        public ActionResult Details(int Id)
        {
            return View();
        }
    }

一、Action 中 return View()的理解

也就是ActionResult，这里return View()其实就是返回html格式的内容给页面显示，而ActionResult是有很多类型的：

· View() – 返回一个 ViewResult.

· PartialView() – 返回一个 PartialViewResult.

· RedirectToAction() – 返回一个 RedirectToRouteResult .

· Redirect() – 返回一个 RedirectResult.

· Content() – 返回一个 ContentResult.

· Json() – 返回一个 JsonResult.

· File() – 返回一个 FileResult.

· JavaScript() – 返回一个 JavaScriptResult.

· RedirectToRoute() – 返回一个 RedirectToRouteResult.

解释：

· ViewResult – 表示一个普通的 ASP.NET MVC view.

· PartialViewResult – 表示一个ASP.NET MVC view的一个片段.

· RedirectResult – 表示重定向到另外一个controller action 或者 URL.

return RedirectToAction("Index"); 

return RedirectToAction(“Index”, “Product”);

return RedirectToAction(“Details”, new {id=53});

· ContentResult – 表示发送一些基本的类型的内容给浏览器，只要是.net的基本类型都可以 比如：string，int，double等等

 public string SayHello()  
 {  
       return "Hello";  
 }

· JsonResult – 返回一个Json类型给浏览器

  
        public ActionResult List()  
        {  
            var quotes = new List<string>  
            {  
                "Look before you leap",  
                "The early bird gets the worm",  
                "All hat, no cattle"  
            };  
              
            return Json(quotes);  
        }

· FileResult – 返回一个文件，用来下载的

        public ActionResult Download()  
        {  
             
            return File("~/Content/CompanyPlans.docx", "application/vnd.openxmlformats-officedocument.wordprocessingml.document", "CompanyPlans.docx");  
        }  
  

· EmptyResult – 一个action没有返回结果

· HttpUnauthorizedResult – 返回HTTP Unauthorized status code.

· JavaScriptResult – 返回一个JavaScript 文件.

· RedirectToRouteResult – 使用route values重定向到另外一个controller的action

二、如何控制Action被调用

1.使用AcceptVerbs

看代码：

        // GET: /Employee/Create  
        [AcceptVerbs(HttpVerbs.Get)]  
        public ActionResult Create()  
        {  
            return View();  
        }   
  
        // POST: /Employee/Create  
        [AcceptVerbs(HttpVerbs.Post)]  
        public ActionResult Create(Employee employeeToCreate)  
        {  
            try  
            {  
                _repository.InsertEmployee(employeeToCreate);  
                return RedirectToAction("Index");  
            }  
            catch  
            {  
                return View();  
            }  
        }  
  
        // DELETE: /Employee/Delete/1  
        [AcceptVerbs(HttpVerbs.Delete)]  
        public ActionResult Delete(int id)  
        {  
            _repository.DeleteEmployee(id);  
            return Json(true);  
        }

就是控制是Get还是Post的时候触发Create这个Action了

http 支持的动作类型：

· OPTIONS – Returns information about the communication options available.

· GET – Returns whatever information is identified by the request.

· HEAD – Performs the same operation as GET without returning the message body.

· POST – Posts new information or updates existing information.

· PUT – Posts new information or updates existing information.

· DELETE – Deletes information.

· TRACE – Performs a message loop back.

· CONNECT – Used for SSL tunneling.

2.使用ActionName

        [ActionName("Edit")]  
        [AcceptVerbs(HttpVerbs.Get)]  
        public ActionResult Edit_GET(Merchandise merchandiseToEdit)  
        {  
            return View(merchandiseToEdit);  
        }

3.使用ActionMethodSelector

namespace MvcApplication1.Selectors  
{  
    public class AjaxMethod : ActionMethodSelectorAttribute  
    {  
        public override bool IsValidForRequest(ControllerContext controllerContext, MethodInfo methodInfo)  
        {  
            return controllerContext.HttpContext.Request.IsAjaxRequest();  
        }  
    }  
} 

在Controller中的代码：

        [AjaxMethod]  
        [ActionName("Index")]  
        public string Index_AJAX()  
        {  
            var selectedIndex = _rnd.Next(_news.Count);  
            return _news[selectedIndex];  
        }

三、一个特殊处理：请求没有定义的Action的处理

    public class CatalogController : Controller  
    {  
         
        public ActionResult Create()  
        {  
            return View();  
        }  
  
        public ActionResult Delete(int id)  
        {  
            return View();  
        }  
  
  
        protected override void HandleUnknownAction(string actionName)  
        {  
            ViewData["actionName"] = actionName;  
            View("Unknown").ExecuteResult(this.ControllerContext);  
        }  
  
  
    }

使用HandleUnkonwnAction，默认情况下返回404 Resource Not Found的异常，你可以重载定义