How to swallow ... exception with specific reason

Question

In this method

    public static void Detach()
    {
        try
        {
            using (var master = new DataContext(@"Data Source=(LocalDB)\MSSQLLocalDB;Initial Catalog=master;Integrated Security=True"))
            {
                master.ExecuteCommand(string.Format("ALTER DATABASE [{0}] SET OFFLINE WITH ROLLBACK IMMEDIATE", DatabaseFile));
                master.ExecuteCommand(string.Format("exec sp_detach_db '{0}'", DatabaseFile));
            }
        }
        catch (Exception e)
        {
           ... // add to log
        }
    }

I can receive exception

System.Data.SqlClient.SqlException (0x80131904): The database 'blablabla.mdf' does not exist. Supply a valid database name. To see available databases, use sys.databases.

This happens if Detach() is called when database is not attached.

My question is: How to swallow only this specific message to avoid logging it?

Text may be localized, so this won't work

if(!(e is SqlException && e.Message.Contains("Supply a valid database name"))) 
    ... // log 

I am not sure if error code is unique for this specific case (google proves it?)

if(!(e is SqlException && e.Message.Contains("0x80131904"))) 
    ... // log 

Of course I can do

try { ... } catch {}

But then I have no chance to get into log something unexpected, what may help me to solve problem in case it appears.

Answer 1

You don't want to check the message - you want to check the SQL specific number. You can use the SqlException.Number property for this.

I would use:

// I think this is right, based on
// http://technet.microsoft.com/en-us/library/cc645936(v=sql.105).aspx
private const int DatabaseDoesNotExistCode = 15010;
...
catch (SqlException e)
{
    if (e.Number != DatabaseDoesNotExistCode)
    {
        ...
    }
}

(I would typically not catch plain Exception... but that's probably a different matter.)