Using the Plantronics SDK with a Delphi application - class

Question

and thank you in advance for any advice / insight / assistance that can be provided.
The Background:
We have a soft phone application that is written in Delphi (XE3) for Windows. The ability to answer an incoming call by activating the answer button an a Plantronics Wireless Headset was recently requested. The MSI files were downloaded and executed, and the Plantronics SDK was converted / altered into a Delphi Library File.
I then started to follow the "First Steps" section of the Plantronics Website. I knew that the "First Steps" code would have to be tweaked to fit the Delphi system.
The Problem:
In adjusting the code to work within Delphi, a few translation problems were encountered and resolved. One such error is proving to be stubborn - When an instance of one specific class is created, the error "Class not registered" is thrown.
"First Steps" code for reference -
// Connect to the Plantronics COM API:
myAppName = "SDK .NET COM sample";
sessionManager = new COMSessionManager();
sessionManager.Register(myAppName, out session);
// Hook to SessionManager events:
sessionManagerEvents = sessionManager as ICOMSessionManagerEvents_Event;
if (sessionManagerEvents != null)
{
sessionManagerEvents.onCallStateChanged += SessionManagerEvents_onCallStateChanged;
sessionManagerEvents.onDeviceStateChanged += SessionManagerEvents_onDeviceStateChanged;
}
Delphi Code:
//Connect to the Plantronics COM API:
plugin_name: "Plugin Name";
the_session: CoCOMSession.Create;
session_manager = new COMSessionManager.Create;
session_manager.Register(plugin_name, the_session);
//Hook to Session Manager Events
state_device_event_args := CoCOMStateDeviceEventArgs.Create;
call_event_args := CoCOMCallEventArgs.Create;
The final line of Delphi Code is the issue. The other three "Create" calls go off without a hitch. The line "call_event_args := CoCOMCallEventArgs.Create;" throws the error "Class not registered", even through it is declared and implemented in the library file along with the other three.
Excerpts from the library file:
Class Declarations:
IID_ICOMStateDeviceEventArgs: TGUID = '{91542BEE-4931-4620-9E96-23AE4001E93F}';
CLASS_COMStateDeviceEventArgs: TGUID = '{335D08FD-8BB5-4EF5-964B-E8A8C010530F}';
IID_ICOMCallEventArgs: TGUID = '{0280956C-C644-4CD8-B124-C8A99E5D505E}';
CLASS_COMCallEventArgs: TGUID = '{705129C3-2265-4F10-9768-0FF8A20234C0}';
Class creation functions:
//Works
class function CoCOMStateDeviceEventArgs.Create: ICOMStateDeviceEventArgs;
begin
Result := CreateComObject(CLASS_COMStateDeviceEventArgs) as ICOMStateDeviceEventArgs;
end;
// Doesn't Work
class function CoCOMCallEventArgs.Create: ICOMCallEventArgs;
begin
Result := CreateComObject(CLASS_COMCallEventArgs) as ICOMCallEventArgs;
end;
Every tutorial / forum answer about resolving the "Class Not Registered" error that I have found has not resolved the issue.
Does anyone have any advice or insight as to what I have been doing wrong?
Thank you.

Answer 1

The issue has been (potentially) resolved by the following -
I had mistakenly thought from the tutorial / first steps section that a "COMCallEventArgs" object needed to be created before it could be used.
Upon further review, the COMCallEventArgs object gets created when necessary at a later point.
More testing needs to be done, but I believe this issue is resolved.