When running a standalone connector, exceptions are handled slightly differently. In this case, QvxLibrary.dll does not send the exception back to QlikView or Qlik Sense. Instead, it re-throws any exception from the method RunStandalone(). You must therefore surround this method call with a try catch block to catch all the exceptions yourself.
The following code example, taken from Standalone.cs within the QvEventLogConnectorElaborate example, shows what it may look like:
try
{
new QvEventLogServer().RunStandalone("", "StandalonePipe", _connectString, _sPath, query);
}
catch (Exception exception)
{
MessageBox.Show(exception.Message, "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
}