为什么RedirectToAction返回null？

Question

我有以下类，其中用户将访问控制器AT/1/2这意味着项目1，步骤2.如果用户输入一个项目而不是一个步骤（第二方法/路线）它应该使用步骤99.如果用户失败要输入任何内容，它应该使用项目1，步骤99.我可以通过手动调用重载方法轻松解决此问题，但我认为我应该能够使用RedirectToAction完成同样的事情。但是，在第二种和第三种方法中，我的单元测试中为v为空。

我的RegisterRoutes样子：

public static void RegisterRoutes(RouteCollection routes) 
{ 
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); 

    routes.MapMvcAttributeRoutes(); //MVC 5 Attribute Routes 

    routes.MapRoute(
     name: "Default", 
     url: "{controller}/{action}/{id}", 
     defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } 
    ); 
} 

我不知道我在这里失踪。

public class ATController : Controller 
{ 
    [AllowAnonymous] 
    [Route("{project}/{step}")] 
    public ActionResult Index(int project, int step) 
    { 
     var m = new ATViewModel(); 
     m.Project = project; 
     m.Step = step; 
     return View(m); 
    } 

    [AllowAnonymous] 
    [Route("{project}")] 
    public ActionResult Index(int project) 
    { 
     var v = RedirectToAction("Index", new { project, step = 99 }); 
     return v; 
    } 

    [AllowAnonymous] 
    public ActionResult Index() 
    { 
     var v = RedirectToAction("Index", new { project = 1, step = 99 }); 
     return v; 
    } 
} 

Answer 1

引用Attribute Routing in ASP.NET MVC 5，有需要的控制器

[RoutePrefix("at")] 
public class ATController : Controller 
{ 
    //GET /at/1/2 
    [AllowAnonymous] 
    [Route("{project}/{step}")] 
    public ActionResult Index(int project, int step) 
    { 
     var m = new ATViewModel(); 
     m.Project = project; 
     m.Step = step; 
     return View(m); 
    } 

    //GET /at/1 
    [AllowAnonymous] 
    [Route("{project}")] 
    public ActionResult Index(int project) 
    { 
     var v = RedirectToAction("Index", new { project = project, step = 99 }); 
     return v; 
    } 

    //GET /at 
    [AllowAnonymous] 
    [Route("")] 
    public ActionResult Index() 
    { 
     var v = RedirectToAction("Index", new { project = 1, step = 99 }); 
     return v; 
    } 
} 

这里的一些小的更新也全部通过（绿色）进行测试时，你的控制器一些单元测试。

[TestClass] 
public class MvcControllerAttributeRouteTests : ControllerUnitTests { 
    [TestMethod] 
    public void Index_Should_Return_ViewResult_With_Model() { 
     //Arrange 
     int project = 1; 
     int step = 2; 
     var controller = new ATController(); 
     //Act 
     var actionResult = controller.Index(project, step); 
     var viewResult = actionResult as ViewResult; 
     //Assert 
     Assert.IsNotNull(viewResult); 
     Assert.IsNotNull(viewResult.Model); 
     Assert.IsInstanceOfType(viewResult.Model, typeof(ATViewModel)); 
     var viewModel = viewResult.Model as ATViewModel; 
     Assert.AreEqual(project, viewModel.Project); 
     Assert.AreEqual(step, viewModel.Step); 
    } 

    [TestMethod] 
    public void Project_Supplied_No_Step_Should_Redirect_To_Index() { 
     //Arrange 
     int project = 1; 
     var controller = new ATController(); 
     //Act 
     var actionResult = controller.Index(project); 
     var result = actionResult as RedirectToRouteResult; 
     //Assert 
     Assert.IsNotNull(result); 
     Assert.AreEqual("Index", result.RouteValues["action"], "the redirection was to at.index action"); 
     Assert.AreEqual(project, result.RouteValues["project"]); 
    } 

    [TestMethod] 
    public void No_Porject_No_Step_Should_Redirect_To_Index() { 
     //Arrange 
     var controller = new ATController(); 
     //Act 
     var actionResult = controller.Index(); 
     var result = actionResult as RedirectToRouteResult; 
     //Assert 
     Assert.IsNotNull(result); 
     Assert.AreEqual("Index", result.RouteValues["action"], "the redirection was to at.index action"); 
     CollectionAssert.Contains(result.RouteValues.Keys, "project"); 
     CollectionAssert.Contains(result.RouteValues.Keys, "step"); 
    } 
}