Query Parameter Value Is Null When Enum Item 0 is Cast with Int32

Question

When I use the first item in a zero-based Enum cast to Int32 as a query parameter, the parameter value is null. I've worked around it by simply setting the first item to a value of 1, but I was wondering though what's really going on here? This one has me scratching my head. Why is the parameter value regarded as null, instead of 0?

Enum LogEventType : int
{
    SignIn,
    SignInFailure,
    SignOut,
    ...
}

private static DataTable QueryEventLogSession(DateTime start, DateTime stop)
{
    DataTable entries = new DataTable();

    using (FbConnection conn = new FbConnection(DSN))
    {
        using (FbDataAdapter adapter = new FbDataAdapter(
            "SELECT event_type, event_timestamp, event_details FROM event_log " +
            "WHERE event_timestamp BETWEEN @start AND @stop " +
            "AND event_type IN (@signIn, @signInFailure, @signOut) " +
            "ORDER BY event_timestamp ASC", conn))
        {
            adapter.SelectCommand.Parameters.AddRange(new Object[] {
                new FbParameter("@start", start),
                new FbParameter("@stop", stop),
                new FbParameter("@signIn", (Int32)LogEventType.SignIn),
                new FbParameter("@signInFailure", (Int32)LogEventType.SignInFailure),
                new FbParameter("@signOut", (Int32)LogEventType.SignOut)});

            Trace.WriteLine(adapter.SelectCommand.CommandText);
            foreach (FbParameter p in adapter.SelectCommand.Parameters)
            {
                Trace.WriteLine(p.Value.ToString());
            }

            adapter.Fill(entries);
        }
    }
    return entries;
}

Answer 1

I do not know this api but it may be a bug. Try passing in a FbDbType enum when defining the params.

http://www.firebirdsql.org/dotnetfirebird/documentation/api/1.7/FirebirdSql.Data.Firebird.FbDbType.html

http://www.firebirdsql.org/dotnetfirebird/documentation/api/1.7/FirebirdSql.Data.Firebird.FbParameter.html

Another option is to try adding the parameters one by one instead of using an object array and the AddRange method.