生成的ToList将不起作用

Question

I'm very new to C# and I'm trying to make a basic little project. When I try to go to the generated index page (On the view -> Add -> View and then I just gave it the name Index and template List)

When I try to use this link to the index page;

<ul><li>@Html.ActionLink("Beheer", "Index", "Competenties")</li></ul>

I keep getting this error.

An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code

Additional information: The model backing the 'DatabankCompetenties' context has changed since the database was created. Consider using Code First Migrations to update the database ( http://go.microsoft.com/fwlink/?LinkId=238269 ).

I tried resetting the Database, rerolling all the tables and using the command update-database, but nothing seems to work.

Answer 1

You modify your Database schema, but you don't migrate the changes. https://msdn.microsoft.com/en-us/data/jj591621.aspx

1. Open the Package Manager Console in Visual Studio
2. Select the project where is the database classes
3. Enable-Migrations command
4. Add-Migration [Name] command
5. Update-Database command

Answer 2

Since you are very new to C# I'll give you a very basic solution, which helped me out quite a few times.

1. Add-Migration (check which migration needs updating)
2. delete the recently added migration and the old one
3. Add-Migration (Now you know which migration needs to be updated, so you can give it the proper name)
4. Delete all the tables in your DB (including _MigrationHistory)
5. Update-Database -verbose