Chapter 20: Creating ActiveX Clients

Using an ActiveX error handler

By default, the ActiveX proxy raises an ActiveX exception when an EAServer component method raises an exception or an internal error occurs. Visual Basic and most other ActiveX scripting tools do not allow you to handle these errors inline. Instead, control transfers to an error handler (specified by on error goto in Visual Basic) or to a system-wide error dialog box. To handle proxy errors inline, you must enable inline exception handling as described in “Handling exceptions inline”.

Structure of an ActiveX exception

In C++, the OLE EXCEPINFO structure describes an ActiveX exception. Different ActiveX-enabled IDEs provide different mechanisms for applications to obtain the EXCEPINFO structure contents.

In Visual Basic, exceptions are mapped to the built-in Err object. The exception number maps to Err.Number and the description is available as Err.Description. You can handle exceptions by activating error handling code with On Error Goto statement or by checking whether Err.Number is > 0.

The proxy type library defines error numbers for client-side errors in the JagORBClientErrNum enumeration and server-side error numbers in the JagORBServerErrNum enumeration.

IDL user-defined exceptions are not supported and are mapped to error number 9000.

Client error numbers

Table 20-1 lists the codes for client-side error numbers defined in the JagORBClientErrNum enumeration:

**Table 20-1: JagORBClientErrNum error codes**
Symbolic error code	Number	Description
jagClNonByteArrayErr	8000	Method arguments of type array can only have a base element type of byte.
jagClMultiDimArrayErr	8001	Multi-dimensional arrays not supported as an argument to a method.
jagClArrayRedimErr	8002	A Fatal Internal Error was encountered while attempting to resize a method argument of type array.
jagClArrayProcErr	8003	A Fatal Internal Error was encountered while processing a method argument of type array.
jagClArrayEmptyErr	8004	An array of size 0 was passed as parameter to a method.
jagClArrayBoundsErr	8005	A Fatal Internal Error was encounterd while attempting to determine the upper bound on a method argument of type array.
jagClNotJagComponentErr	8006	The component being instantiated is not a valid EAServer component or was not registered in the Windows Registry.
jagClOutOfMem	8007	The Application failed to acquire memory from the Operating System.
jagClCreateFactErr	8008	The EAServer Proxy Server could not instantiate a Factory Object. Please contact Sybase Technical Support.
jagClTypeLibErr	8009	The type library for the Component could not read from the Windows Registry. Please check if a valid directory location was specified for the Type Library while registering the component.
jagClTypeInfoErr	8010	The type information for the Component could not read from the Type Library. Please regenerate TLB and REG files for the component using EAServer Manager.
jagClMethInfoErr	8011	The metadata for the method or component could not be read from the Windows Registry or the method is using parameter types that are not presently supported in the EAServer ActiveX Proxy.
jagClMethNameErr	8012	The metadata for the method invoked on component could not be read from the Windows Registry. Please regenerate TLB and REG files for the component using EAServer Manager.
jagClCompNameErr	8013	The component name for the component being instantiated could not read from the Windows Registry.
jagClPkgNameErr	8014	The package name for the Component being instantiated could not read from the Windows Registry.
jagClPxyCreateErr	8015	Component creation failed.
jagClPxyDestroyErr	8016	Component deletion failed.
jagClPxyFuncDescErr	8017	The metadata information for the method could not read from the type library.
jagClArgCountErr	8018	There was a mismatch between the number of parameters passed to method and the number of parameters as described by the information in the type library.
jagClInternalErr	8019	An error was encountered while invoking an EAServer method.
jagClParamInfoErr	8020	The type information for a method parameter could not be read from the Type Library.
jagClTypeMismatchErr	8021	There is a mismatch between type of the value passed as an argument with its specified type in the Type Library.
jagClConversionErr	8022	The data conversion attempted is presently not supported.
jagClArgUpdateErr	8023	An error was encountered while updating an input-output or output parameter for a method.
jagClRetValSetErr	8024	An error was encountered while updating the return value for a method.
jagClRecsetArgErr	8025	The ResultSet type cannot be passed as a parameter in either the input or input-output modes by an EAServer ActiveX application.
jagClUnsuppTypeErr	8026	An unsupported OLE Automation type was used as a parameter in a method.
jagClAxConvertErr	8027	An error was encountered while converting a input-output method parameter received from the server.
jagClJagConvertErr	8028	An error was encountered while converting a input parameter prior to method invocation.
jagClNoInitErr	8029	an EAServer component instance must be created prior to invoking a method.
jagClRecordsetCreateErr	8030	An internal error was encountered while creating the Recordset object.
jagClRecordsetMoveErr	8031	Attempt to call MoveNext on a RecordSet which has its EOF property as TRUE.
jagClIteratorPosErr	8032	An invalid position was specified while attempting to retrieve an element from a collection.
jagClInvalidMethodErr	8033	The only method supported on the generic Object type is Narrow_.
jagClNarrowFailErr	8034	The object reference cannot be narrowed to the interface name specified.
jagClInvalidIntfErr	8035	The fully scoped interface name passed as an argument to the Narrow_ method is invalid.
jagClOrbInitErr	8036	An internal error was encountered while initializing client-side ORB.
jagClOrbStrToObjErr	8037	An internal error was encountered while invoking the ORB.string_to_object method.

Server error numbers

Table 20-2 lists the codes for server-side error numbers defined in the JagORBServerErrNum enumeration:

**Table 20-2: JagORBServerErrNum error codes**
Symbolic error code	Number	Description
jagSrvMethExcepErr	9000	The method implementation threw an user-defined exception while executing on the server.
jagSrvMethInvalidErr	9001	The method name is either invalid or is presently not defined in the component's interface.
jagSrvMethInvalidArgErr	9002	The invocation of the method on the server failed because an invalid number of parameters was passed or a parameter type mismatch occurred.
jagSrvMethNotImplErr	9003	The invocation of the method on the server failed because the component does not implement the method.
jagSrvCompPermErr	9004	The invocation of the method on the server failed because user does not have the permissions to instantiate the component.
jagSrvCompDeployErr	9005	The invocation of the method on the server failed because component implementation was not deployed on the server.
jagSrvInternalErr	9006	The invocation of the method on the server failed due a fatal internal error.
jagSrvArgCountErr	9007	The invocation of the method on the server failed because an invalid parameter type was used by the method.
jagSrvSrvConnectErr	9008	The requested operation failed since the client could not to acquire connection to the server.
jagSrvConversionErr	9009	The invocation of the method on the server failed due to a data conversion error.
jagSrvFreeMemErr	9010	The invocation of the method on the server failed while releasing memory resources.
jagSrvIntfReposErr	9011	The invocation of the method on the server failed while trying to access the interface repository.
jagSrvOutOfMemErr	9012	The invocation of the method on the server failed while trying to acquire memory from the Operating System.
jagSrvOutOfResErr	9013	The invocation of the method on the server failed since it could not acquire the necessary resources.
jagSrvSrvRespErr	9014	The invocation of the method on the server failed because there was no valid response from the server.
jagSrvInvObjrefErr	9015	The invocation of the method on the server failed because the object reference is invalid.

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