Deleting a record with an intermediary "Are you sure?" page

In this recipe, we are going to present a list of data with an option to delete one of the records. When the user clicks on the link to delete a record, they will be taken to a page confirming that they actually want to delete the record. From there, the user can post the ID to the controller and actually perform the delete on the record they selected.

Getting ready

This recipe will build from the first recipe. By that I mean to say that we will be using the Product class and ProductRepository along with NBuilder to generate our data for us.

How to do it...

  1. To start off we need to make sure that we have the Product and ProductRepository class in our Models folder (you can get this from any of the previous recipes).
  2. Then we need to open up our ProductRepository and add a method called GetProduct in addition to the existing GetProducts method.

    ProductRepository.cs: 

    public Product GetProduct(int productId)
{
Product product = Builder<Product>.CreateNew().With(x=>x.ProductId = productId).Build();
return product;
}
  3. Next, we need to ensure that we are passing a collection of data out to our index view.

    Controllers/HomeController.cs: 

    public ActionResult Index()
{
ViewData["Message"] = "Welcome to ASP.NET MVC!";
ViewData["Products"] = new ProductRepository().GetProducts();
return View();
}
  4. With our controller passing out the appropriate collection of data, we need to update our view to show a list of product details. At the top of each record, we will add a link that will allow us to delete the records.

    Views/Home/Index.aspx: 

    <fieldset>
<legend>Products</legend>
<% List<Product> products = ViewData["Products"] as List<Product>; %>
<% foreach (Product p in products) { %>
<div class="display-label">
<%= Html.ActionLink("Delete", "ConfirmDelete", new {@id=p.ProductId}) %>
</div>
...
<hr />
<% } %>
</fieldset>
  5. Notice that this link points to the ConfirmDelete action. Let's add that now. In the home controller we will add a new action called ConfirmDelete. This action will instantiate the appropriate Product and pass it down to the view to prompt the user to be sure that they want to delete that record or not.

    Controllers/HomeController.cs: 

    public ActionResult ConfirmDelete(int id)
{
Product product = new ProductRepository().GetProduct(id);
return View(product);
}
  6. Now right-click on the ConfirmDelete method name and choose to add a new view. Make this view strongly typed to the Product class and select the details view. Then open up the new view and add this form to the top of the page, which will allow the user to post their request to delete the appropriate record.

    Views/Home/ConfirmDelete.aspx: 

    <% using(Html.BeginForm("Delete", "Home", new {@id=Model.ProductId})) {%>
<div>
Are you sure you want to delete this record?<br/>
<%= Html.HiddenFor(m=>m.ProductId) %>
<input type="submit" value="Delete Record!" />
</div>
...
}
  7. This form posts the appropriate ProductID to the delete action where the appropriate data deletion logic can be placed. Let's add that new action now. Notice that we are enforcing this action to accept posted data only with the [HttpPost] attribute.

    Controllers/HomeController.cs: 

    [HttpPost]
public ActionResult Delete(int id)
{
//perform delete logic on your data
return View();
}
  8. Right-click on the new Delete action and select Add View. This view can either be strongly typed or not...that is up to you. Add a message in your view letting your user know that you have to delete the record as they requested. I also provided a link back to the home page.

    Views/Home/Delete.aspx: 

    <h2>Record Deleted</h2>
<%= Html.ActionLink("Home", "Index") %>
  9. Done! Hit F5 and walk through a record deletion simulation.

How it works...

This recipe is more of a lesson in workflow rather than complex cutting edge technology! In this recipe we listed some data. Each piece of data is linked to a deletion confirmation page, where we asked the user in a very Windows manner if they were sure they wanted to delete the specified bits of data. If they clicked the button to delete the data, we deleted it and told the user that we did so.

It is important to note however that we did not perform the deletion on a GET request (standard HTML link requesting a page). You should stay away from GET requests that perform any action on your application other than reading data. Instead, use a post to do actions such as deletes. Think of it this way...if Google were to spider your site and crawl a bunch of links that requested your delete links by way of a GET request, you might wake up and find all your data deleted! There are of course other ways to stop this from happening but this is a quick and easy rule to remember, just in case things don't go as planned.

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