How to swallow ... exception with specific reason

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.

Jon Skeet
people
quotationmark

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.)

people

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