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Updating Our Controller to Handle Updates

9:43 with James Churchill

Let’s start work on our “Edit Entry” page by updating our controller to handle updates.

Teacher's Notes
Video Transcript
Downloads

Follow Along

To follow along commiting your changes to this course, you'll need to fork the aspnet-fitness-frog repo. Then you can clone, commit, and push your changes to your fork like this:

git clone <your-fork>
cd aspnet-fitness-frog
git checkout tags/v5.1 -b updating-our-controller-to-handle-updates

Additional Learning

For more information on the DRY (Don’t Repeat Yourself) design principle, see this Wikipedia page.

Don’t Repeat Yourself

For more information about access modifiers check out this page on MSDN.

Access Modifiers

Keyboard Shortcuts

CTRL+PERIOD - Opens the quick actions popup
CTRL+SHIFT+B - Build solution

[MUSIC] 0:00

In this section, we'll be updating the fitness frog web app with the ability to 0:04

update and delete entries. 0:09

Once those features are in place, our web app will be completed. 0:11

In this video, we'll be implementing the ability to update entries The Edit Entry 0:16

page, as you're about to see, is very similar to our Add Entry page. 0:21

Let's see how this will allow us to share code between the two pages. 0:26

Here's our EntriesController class. 0:30

If we navigate to the EditAction method. 0:32

We can see that aside from checking if the ID parameter is null 0:35

it's currently just returning the Edit View. 0:39

Let's add some TODO comments to plan out the changes that we need to make. 0:42

First, we need to update this Action Method to make a call into the repository 0:46

to get the entry for the provided ID parameter value to do 0:51

get the requested entry from the repository. 0:56

But also make sure that an entry was found in if not return a status of not found. 1:03

TODO Return a status of "not found" 1:08

if the entry wasn't found. 1:15

Lastly, we need to pass the entry to our view.TODO Pass that entry into the view. 1:21

We also need to add a corresponding Post action method, just like we did for 1:30

the ad entry page. 1:34

I'll go ahead and stub out that method now. 1:36

Public ActionResult Edit(). 1:38

It'll accept an Entry, and 1:47

return a call to View passing in the entry. 1:50

And also add the HttPost attribute. 1:57

The post version of our EditAction method will look 2:02

very similar to the add post action method. 2:05

Let's scroll up a bit to the Add method and 2:08

split our code editor by clicking on window Split. 2:10

Now, we can scroll the bottom window down to our Edit post action method, okay. 2:15

First, we need to validate the entry. 2:22

Validate the entry and if the entry is valid use the repository to 2:29

update the entry and then redirect the user to the entry's list page. 2:33

If the entry is valid 2:40

Use the repository to update the entry. 2:46

Redirect the user. 2:54

To the entries list page. 2:58

Lastly, we need to populate the activities select list items ViewBag property. 3:00

Populate the activities select 3:09

list items ViewBag property. 3:13

We can remove the split by dragging the divider down to the bottom of the editor. 3:18

Now, let's go back and implement our TODOs. 3:23

To get the entry, we just in to make a call to our repositories get entry method. 3:27

Entry, entry,equals 3:31

entriesRepository.GetEntry(id). 3:36

Don't forget, the ID parameter is a nullable int. 3:44

So, we need to cast it to an int in order to pass it into the get entry method. 3:48

To return a status of not found if the entry wasn't found, 3:55

we just need to check if the entry variable is null. 3:59

And if it is, return a call to the HttpNotFound method. 4:03

If (entry = null) 4:07

return HttpNotFound. 4:12

Remember,, as we saw in an earlier course every controller inherits from the N.B.C. 4:19

controller base class. 4:25

Which provides us with a number of convenience methods for 4:27

returning a variety of action results. 4:30

One of those methods is the HttpNotFound method. 4:33

Our last change to make to this method, is the easiest one to make. 4:38

We just need to pass the entry variable into our View method call. 4:41

Now, on to the Post action method. 4:50

First, we need to validate the entry just like we did in the Add method. 4:53

Here's our server validation rule that ensures the duration field value is 4:59

greater than 0. 5:04

We could just copy and paste this code down into our edit method. 5:05

But a better approach would be to extract this code into its own method. 5:10

Then we could call that method from the Add an EditPostAction methods. 5:14

Visual Studio makes extracting code into a method easy to do. 5:19

Just select these lines of code and 5:23

press control period to open the list of suggested quick actions. 5:25

Then press Enter to select the only item in the list, extract method. 5:29

Visual Studio will prompt us to name the new method. 5:34

Let's name the method ValidateEntry and press enter to complete the refactoring. 5:37

Now, the Add method is calling the validate entry method 5:45

to validate the entry. 5:49

And here's our new ValidateEntry method. 5:50

The method is using the private access modifier, 5:55

which makes it visible to just other members of this class. 5:58

If you'd like to learn more about access modifiers or 6:02

need a refresher, see the teachers notes for links to additional resources. 6:05

Visual Studio created the new method right below our Add method. 6:10

Since this method will be called from other methods in this class, 6:14

we're gonna move this method to the bottom. 6:17

Now, we can update the EditPostAction method with a call to our new 6:22

ValidateEntry method. 6:26

Remember the dry, don't repeat yourself design principle. 6:31

By not repeating our server validation code, we're keeping our code dry. 6:36

Another advantage that we gain by having our service side validation 6:40

in a single method is that if we ever need to change our validation logic 6:44

we only have to update our code in one place. 6:49

Let's tackle our next TODO. 6:52

To check of an entry is valid we need to add an if statement that checks 6:56

if the ModelState IsValid property is true. 7:00

Then, inside of the if statement we can call the repositories update entry method. 7:03

And lastly, return a call to the control or base classes RedirectToAction method 7:09

passing an index for the action method name to redirect to. 7:15

That completes this TODO. 7:19

For our last TODO, 7:24

we need to populate the activities select list items ViewBag propert. 7:25

And just like our service side validation the code that we need 7:30

is already available in the add post action method. 7:33

Actually, this code is already in two places. 7:37

It's also in our Add get action method. 7:40

That reminds me we need to populate the activity select list 7:44

items view big property on every request. 7:48

We forgot to do that on our edit GetAction method. 7:51

Lets add a TODO comment here to remind us about that. 7:55

TODO Populate the activities 7:57

select list items ViewBag property. 8:03

Let's scroll back up to the add GetAction method and 8:10

extract the ActivitesSelectListItems set up code into its own method. 8:13

Select the code, press Ctrl+period, 8:18

press Enter to select the extract method quick action, 8:23

name the method SetUp ActivitiesSelectListItems, 8:27

and press Enter to complete the refactoring. 8:35

And just like we did with the ValidateEntry method, 8:39

let's move the new method to the bottom of the class. 8:42

Now we can update the Add post action method and 8:50

our edit methods to call the new method. 8:53

I'll just copy this line of code and paste it here. 8:56

Here. 9:04

And here. 9:06

And that completes the changes to our controller. 9:09

Let's try building our project by pressing Ctrl+Shift+B. 9:12

Here in the output window we can see that our project was successfully built. 9:17

If you're using GitHub, let's commit our changes. 9:21

Enter a commit message of, Updated the controller 9:26

to support the "Edit Entry" page, and click the Commit All button. 9:31

After the break we'll turn our attention to the View. 9:40

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