Question

I am using MVC preview 2 framework to develop web sites and I am following MVCStorefront tutorials to get a good feel on MVC.

Can you tell me why I can’t use RenderView() method ?

Am I missing something or can I use View() instead ?
What’s the difference between these methods..

Thanks

Here is where Rob is using RenderView in his tutorial.

[TestMethod]
    public void CatalogController_IndexMethod_ShouldReturn_Categories_And_Data_For_Parent1() {

        CatalogController c = new CatalogController(_repository);

        RenderViewResult result = (RenderViewResult)c.Index("Parent1", "Sub10");

        CatalogController.CatalogData data = (CatalogController.CatalogData)result.ViewData;

        Assert.IsNotNull(data.Category);
        Assert.IsNotNull(data.SubCategory);
        Assert.IsNotNull(data.SubCategory.Products);
        Assert.IsTrue(data.SubCategory.Products.Count() > 0);

        Assert.IsNotNull(result);
    }

I can’t use RenderView. It says ” the name ‘RenderView’ does not exist in the current context

Here’s the link :
http://www.asp.net/learn/mvc-videos/video-357.aspx

Here is an index method from the CatalogController class :

public ActionResult Index(string category, string subcategory) {

        //instantiate the service
        CatalogService svc = new CatalogService(_repository);

        //the ViewData class
        CatalogData data = new CatalogData();

        //pull all the categories for the navigation
        data.Categories = svc.GetCategories();

        //pull the category based on subcategory name
        data.Category = data.Categories.WithCategoryName(category);

        //catch for bad data
        if (data.Category == null) {

            data.Category = data.Categories.DefaultCategory();

            data.SubCategory = data.Category.SubCategories[0];

        } else {

            data.SubCategory = data.Categories.WithCategoryName(subcategory);

            //catch for bad SubCategory
            data.SubCategory= data.SubCategory ?? data.Category.SubCategories[0];

        }
        return RenderView("Index",data);
    }

I am also having a problem with the casting of result.ViewData in CatalogData type which is class that contains data. It says : Cannot convert type System.Web.Mvc.ViewDataDictionary to Commerce.MVC.Web.Controllers.CatalogController.CatalogData

Answer 1

The video you are watching is unfortunately outdated – it is from ASP.NET MVC 1.0 Preview 2. Since then ASP.NET MVC 1.0 RTM has shipped and there are previews of ASP.NET MVC 2 available.

In ASP.NET MVC 1.0 Preview 2 and earlier action methods returned ‘void’ so they had to explicitly perform a result, such as render a view:

public void Index() {
    // do some work...
    RenderView("Index");
}

In ASP.NET MVC 1.0 Preview 3 (Refresh?) and newer, action methods return a result object, which then actually performs the result:

public ActionResult Index() {
    // do some work...
    return View("Index");
    // or you could also just say "return View();" and MVC figures out the view name
}

The main reason this changed is that it allows for much better unit testing. Action methods now only perform the “application logic” and don’t worry about exactly how to render a view. The unit test can simply inspect the results of the application logic and then verify that the next desired step was “render a view.”

A lot of type names and method names have changed as well to make them shorter and simpler to use. For example, RenderView is just View and RenderViewResult is just RenderView.