Using Our Generic Base Repository Class

Now, that we have our generic base repository class, 0:00 let's update our comic books and comic book artists repositories to use it. 0:03 First, let's update the comic books repository class. 0:08 To start inherit from the base repository class, 0:12 specifying comic book for the T entity generic type parameter. 0:15 Colon, BaseRepository<ComicBook> and we get build errors. 0:20 The error in the class is telling us that we didn't implement the abstract get and 0:28 getList methods. 0:33 We'll get to that in just a bit. 0:35 For now, let's move on to the error with the constructor. 0:36 There is no argument given that corresponds to the required 0:40 formal parameter context of base repository of type ComicBook, 0:43 base repository context. 0:47 The constructive for the base class require us the pass in a context instance. 0:51 To do that we can use the base keyword in order to call the base class constructor 0:56 and pass in the context parameter that is being passed to the ComicBook Repository 1:01 constructor :base(context), then pass in the context parameter. 1:07 We no longer need the context private field, 1:13 as we'll use the context property in the base class. 1:15 The green squiggle under the getlist method name 1:18 is telling us that our method is hiding the inherited method of the same name. 1:21 This error is easy to fix. 1:26 We just need to add the override keyword to make our intentions clear to 1:27 the compiler. 1:31 public, override, and do the same for the Get method. 1:33 Public, override. 1:40 We also need to remove the add, update, and delete methods. 1:48 That might seem counter-intuitive but remember, 1:53 the base repository class is providing the implementations for these methods. 1:56 To resolve the remaining errors, we need to replace all references to 2:01 the _context private field with the base class's Context property. 2:05 Now, let's finish up by updating the ComicBookArtistsRepository class. 2:17 Inherit from the BaseRepository class, 2:25 specify ComicBookArtist for the T entity generic type parameter, 2:28 update the constructor to call the base class constructor. 2:32 And remove the context private field. 2:40 The signature for the get method currently doesn't match the base classes get method. 2:45 If we put our cursor on the class name and press control period or 2:51 dot, we can select to implement the abstract class. 2:55 Which will add overrides for the missing methods, then we can cut and 2:59 paste the old get method implementation down into the new get method. 3:03 And remove the old get add and delete methods. 3:08 The new get method supports the ability for the caller to specify whether or 3:14 not the related entities are included or not. 3:18 So, we need to update our method implementation 3:21 to respect that parameter value. 3:24 To start, let's call the AsQueryable method on the ComicBookArtists DB 3:26 set property in order to get a IQueryable object. 3:31 Var comicBookArtist equals 3:34 Context.ComicBookArtists.AsQueryable. 3:38 Then, let's add a conditional statement that checks if the include related 3:45 entities parameter is set to true. 3:49 If include related entities, and within the if statement code block we can 3:52 add the calls to the include method to eagerly load the related entities. 3:57 ComicBookArtists equals comicBookArtists. 4:02 Then, cut and paste the include method calls to there. 4:09 Then finish up with returning the result of a query to retrieve the comicBookArtist 4:16 with the passed in ID parameter value. 4:21 Looks like we can just modify this to suit our purposes. 4:23 Return comicBookArtists where cba goes to cba.Id == id and 4:26 then calling SingleOrDefault. 4:32 The original version of the repository didn't include a method 4:39 to get a collection of comic book artists. 4:43 But the base class requires us to override its abstract getList method. 4:45 Since our web app doesn't need a method to get a list of comic book artists, 4:50 we can just leave the step-out method that throws a new instance of 4:55 the NotImplementedException class and that's it. 4:59 Now, let's run and test our web app. 5:07 Here is our list of Comic Books, 5:13 let's add a new Comic Book Bone and then issue number 5. 5:15 Jeff Smith for the artist and script for the role. 5:27 Here's the detail for that new issue, let's add another artist. 5:33 Jeff Smith again, this time pencils for the role. 5:40 Here's that new artist in his role, let's delete that artist 5:46 And delete the comic book. 5:54 Looks like everything's still works as expected. 5:59