contosouniversity | sample web app for a fictional university

You are trying to get a connection string called SchoolContext but you only have one in the config called DefaultConnection. So either fix your code:

According to your code and description, it looks that in the Album.cshtml page, you will list the albums, and if click the "delete" hyperlink, it will redirect to the Delete.cshtml page and show the selected album, after that, click the "Delete" button to delete the item and redirect to the Index page. If that is the case, please refer the following steps to modify your code.

First, in the Album.cshtml page:

Since the Delete.cshtml page located in the "Albums" folder, when you add the hyperlink ( tag), the asp-page attribute should like this: asp-page="/Albums/Delete".

The tag like this: Delete.

Second, in the Delete.cshtml.cs file:

If you check the Album.cshtml.cs file or use F12 developer tool to check the parameter, you can see the id is a string value, instead of int type. So, change the code as below:

Here is a demo to show Courses with DataTable: Controller(I use fake data to test):

The constructor gets an instance of ContosoUniversity.Data.SchoolContext (injected, for example) and then you set it to a field called _context. Both variables are referencing the same object. If you didn't want to have two different names, you would use "this" like this:

It's a graph of data, so it would be: