📓 Lists and Redirects in a Controller

We can display a single item in our To Do List but that's not very helpful in itself. After all, this is a list of things to do, not a single item.

In this lesson, we'll update our controller to return a list of to dos. In the process, we'll also cover using redirects to DRY up our code. In the next lesson, we'll update our index.cshtml view to display our list.

Let's change our controller code to pass in multiple Items to the view, not just a single Item. Note that this will not compile until we update our views, in the next lesson:

HomeController.cs

...
using System.Collections.Generic;

namespace ToDoList.Controllers
{
  public class HomeController : Controller
  {

    [HttpGet("/")]
    public ActionResult Index()
    {

      List<Item> allItems = Item.GetAll();
      return View(allItems);
    }

    ...

    [HttpPost("/items")]
    public ActionResult Create(string description)
    {
      Item myItem = new Item(description);
      return RedirectToAction("Index");
    }
  }
}

First, we need to update our Index() route method so that the route has access to all Items. We'll use the static GetAll() method to store a List of Items in the variable allItems. We then pass allItems to the view.

Note that we also need to add using System.Collections.Generic; to our file now that we've added a List to our controller.

We also make an update to our Create() route method as well. As we discussed in the last lesson, this route only needs to create a new Item. It doesn't care about updating a view. While we could add List<Item> allItems = Item.GetAll(); to our Create() method, it wouldn't be very DRY.

Instead, we can use a method called RedirectToAction() to redirect to another route. RedirectToAction() takes a route method as an argument. RedirectToAction("Index"); tells the server to invoke the Index() route after the Create() route has been invoked. This means we don't have to repeat the code in Index(). We can just tell Create() to redirect to Index() instead.

In the next lesson, we'll update our view to display a List of Items with loops and conditionals.