C/Front: Handling fatal exceptions

jhoek

My Delphi 7.0 application uses cfront.dll to read information from a Navision database. There are cases however, when an end user's license does not contain the required C/Front granule. In that case, the application should continue to work, but with limited functionality.

Currently, I seem to be unable to prevent the exception that is generated because of the missing granule from terminating my application. Does anyone know how I can "preview" exceptions, and decide to ignore them, even if C/Front considers them fatal?

apprins

Hi Jan,

Create Delphi functions like these:

procedure ExceptionHandler(ErrorCode: DBL_S32; IsFatal: DBL_BOOL) cdecl far;
begin
  raise Exception.Create(ExceptionMsg);
end;

procedure MessageHandler(Msg: PChar; MsgType: DBL_U32; ErrorCode: DBL_S32) cdecl far;
begin
  ExceptionMsg :=
    Format(
      'Error %d in module %d.'#13#10'%s',
      [Errorcode mod $10000, Errorcode div $10000, Msg]);
end;

and then register these functions like this:

DBL_SetExceptionHandler(@ExceptionHandler);
DBL_SetMessageShowHandler(@MessageHandler);

HTH

BTW: I'm currently developing Delphi DataSet components which enable you to show Navision data in Delphi Data aware controls like DBGrid, DBEdit and so on. These components will greatly reduce development time. I probably will make them available as shareware for a fair price.

André P. Prins
Twain Development