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sql-serverasp.net-mvcentity-frameworklocaldb

How to simulate a data exception with localdb

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.

Solution

  • 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;..."