MVC中的Action方法的返回值一般有以下几种：
类型 | s说明 |
EmptyResult | 不进行任何操作 |
ContentResult | 将指定内容作为文本输出 |
JsonResult | 输出JSON字符串 |
JavaScriptResult | 输出JavaScript |
RedirecResult、RedirectToRouteResult | 重定向到给定的URL中 |
FileResult(抽象类)FilePathResult、FileContentResult、FileStreamResult | 文件输出 |
ViewResultBase(抽象类)ViewResult、PartialViewResult | 调用视图输出 |
Controller控制器代码如下：
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.Mvc;using System.IO;namespace MvcActionReturnType.Controllers{ ???public class HomeController : Controller ???{ ???????/// <summary> ???????/// 1、返回一个ViewResult对象 ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult Index() ???????{ ???????????return View(); ???????} ???????/// <summary> ???????/// 2、返回一个json格式的数据 ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult Json() ???????{ ???????????var book = new { BookId = 1, BookName = "MVC框架" }; ???????????return Json(book, JsonRequestBehavior.AllowGet); ???????} ???????/// <summary> ???????/// 3、返回JavaScript ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult JavaScript() ???????{ ???????????string js = "<script>alert(‘Welcome to ASP.NET MVC‘)</script>"; ???????????return JavaScript(js); ???????} ???????/// <summary> ???????/// 4、返回FilePath ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult FilePath() ???????{ ???????????//return File("~/Content/校长 - 带你去旅行.mp3", "audio/mp3"); ???????????return new FilePathResult("~/Content/校长 - 带你去旅行.mp3", "audio/mp3"); ???????} ???????/// <summary> ???????/// 5、返回FileContent ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult FileContent() ???????{ ???????????string content = "Welcome To ASP.NET MVC"; ???????????byte[] contents = System.Text.Encoding.UTF8.GetBytes(content); ???????????return File(contents, "text/plain"); ???????} ???????/// <summary> ???????/// 6、返回FileStream ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult FileStream() ???????{ ???????????string content = "Welcome To ASP.NET MVC"; ???????????byte[] contents = System.Text.Encoding.UTF8.GetBytes(content); ???????????FileStream fs = new FileStream(Server.MapPath("~/Content/2 开发环境下载安装说明.doc"), FileMode.Open); ???????????return File(fs, "application/msword"); ???????} ???????/// <summary> ???????/// 7、返回 ContentResult ???????/// </summary> ???????/// <returns></returns> ???????public ActionResult ContentResult() ???????{ ???????????string content = "<h1>Welcome To ASP.NET MVC</h1>"; ???????????return Content(content); ???????} ???????public ActionResult About() ???????{ ???????????ViewBag.Message = "Your application description page."; ???????????return View(); ???????} ???????public ActionResult Contact() ???????{ ???????????ViewBag.Message = "Your contact page."; ???????????return View(); ???????} ???}}视图代码如下：
@{ ???ViewBag.Title = "Home Page";}<div> ???1.输出json ???<p> ???????@Html.ActionLink("生成Json", "Json"); ???</p> ???2.输出js ???<script src=@Url.RouteUrl(new { action="JavaScript"}) type="text/javascript"> ???</script> ???<p> ???????@(Url.RouteUrl(new { controller = "home", action = "JavaScript" })); ???????@Html.ActionLink("生成JavaScript", "JavaScript"); ???</p> ???3.播放音乐 ???<p> ???????@Html.ActionLink("播放MP3", "FilePath"); ???</p> ???4.查看文本文件 ???<p> ???????@Html.ActionLink("查看文件内容", "FileContent"); ???</p> ???5.链接文件流 ???<p> ???????@Html.ActionLink("访问Doc", "FileStream"); ???</p> ???6.输出文本 ???<p> ???????@Html.ActionLink("输出文本", "ContentResult"); ???</p></div>请看下面的两段代码：
public int Sum(int num1, int num2){ ??????int sum = num1 + num2; ??????return sum;}public ActionResult Sum2(int num1, int num2){ ??????int sum = num1 + num2; ??????return Content(sum.ToString());}有些时候，我们希望把Action定义成一种更自然的形式，比如我们希望Action Sum2做一个求和的计算，传入的参数是整数，计算的结果也是整数，那么可不可以返回一个整数的结果呢？
如上面的两个方法所示，两个方法的效果是等价的，也就是会把整形的数据转换成字符串类型，然后封装成ContentResult类型，这个过程是MVC框架自动帮助我们完成的。
返回的值 | 说明 |
null | EmptyResult |
void | EmptyResult |
对象(ActionResult之外的类型) | ContentResult |
在Action方法中，任何类型的返回值都是可以的，如果他不是ActionResult类型，会封装成ActionResult类型的对象，如上表所示。
MVC基础教程 ???Action的方法返回值
原文地址：https://www.cnblogs.com/guoyu8/p/9944701.html