How to simulate a data exception with localdb

Question

I'm using a LocalDB database with EntityFramework on an ASP.NET MVC project.

How can I simulate a connection failure to test the following try...catch block?

try
{
   if (ModelState.IsValid)
   {
      db.Entry(course).State = EntityState.Modified;
      db.SaveChanges();
      return RedirectToAction("Index");
   }
}
catch (DataException)
{

   ModelState.AddModelError("", "Unable to save changes.");
}

I've tried trying to take the database offline in SQL management studio, but it just hangs. I can't stop the SQL service as LocalDB doesn't run as a service.

score 1 · Answer 1 · answered Sep 06 '13 at 10:25

1

You can stop a LocalDB instance even though it doesn't run as a service, you can use the SQLLocalDB.exe tool to do this:

SqlLocalDB Utility

answered Sep 06 '13 at 10:25

steoleary

8,968
2
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Except everytime I stop the instance, and then run my code, LocalDB starts back up again...! – Evonet Sep 06 '13 at 10:35

Krzysztof Kozielczyk · Accepted Answer · 2013-09-06T16:35:36.017

1

Have you tried giving it a non-existing name of LocalDB instance? Just put this in your connection string for this test:

Server=(localdb)\missing_instance`

(if you embed this connection string in code don't forget to escape the \ character :-))

connectionString="Server=(localdb)\\missing_instance;..."

edited Sep 06 '13 at 16:35

answered Sep 06 '13 at 16:11

Krzysztof Kozielczyk

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How to simulate a data exception with localdb

2 Answers2