Managing subscription events

The signature of the methods to which event handler delegates point takes the form:

void <method name> ( object sender, <object derived from EventArgs> args )

The first argument is a reference to the request object. As it is passed as a System.Object, you must cast it to the appropriate type of the request object before using it. The following example shows how to cast the request sender as an InstrumentLookup object:

public void doInstrumentLookup()
{
  InstrumentLookup m_req = new InstrumentLookup(
     tt_net_sdk.Dispatcher.Current,
     MarketId.CME, ProductType.Future, "CL", "CL Dec19");
  m_req.OnData += new EventHandler(m_req_OnData);
  m_req.GetAsync();
}

void m_req_OnData(object sender, InstrumentLookupEventArgs e)
{
  InstrumentLookup m_req = (InstrumentLookup)sender;
  /* code omitted */
}