Using multiple ActiveX controls

Posted by Connie Cole on March 19, 2008


I have recently added a Serial interface (ActiveX control - Greenleaf CommX) to my standalone GUI application that contains a Map (ActiveX control - MapInfo MapX) and receives, forwards, and maps data from 2 different interfaces, at or near real time. Works great if both interfaces are TCP/IP, using the Delphi supported controls. However, Delphi 7 does not have Comm port controls, so I have implemented the Greenleaf control. I am using event-driven programming, no explicit thread creation. I have tried using the ActiveX.CoInitialize and CoUninitialize methods to synchronize the processing within the Serial control and the Map control, with no success. Receiving and transmitting Serial data works without a hitch, but if I receive data from the other interface and try to write it to the map while receiving data from the Serial control, I have lost access to the Map control, so unrecoverable errors occur. I have tried looking for literature that thoroughly explains what is needed to use multiple ActiveX controls simultaneously and have had no luck so far. I'm desperate!

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