Localized Member Names

An application may expose a set of objects whose members have names that differ across localized versions of a product. This poses a problem for programming languages that want to access such objects, because it means that late binding is sensitive to the locale of the application. The IDispatch and virtual function table (VTBL) interfaces allow software developers a range of solutions that vary in cost of implementation and quality of national language support. All methods of the IDispatch interface that are potentially sensitive to language are passed an LCID.

Following are some of the possible approaches a class implementation may take:

• Accept any LCID and use the same member names in all locales. This is acceptable if the interface will typically be accessed only by advanced users. For example, the member names for OLE interfaces will never be localized.
• Simply return an error (DISP_E_UNKNOWNLCID) if the caller's LCID doesn't match the localized version of the class. This would prevent users from being able to write late-bound code which runs on machines with different localized implementations of the class.
• Recognize the particular version's localized names, as well as one language that is recognized in all versions. For example, a French version might accept French and English names, where English is the language supported in all versions. This would constrain users to use English when writing code that runs in all countries,.
• Accept all LCIDs supported by all versions of the product. This means that the implementation of GetIDsOfNames would need to interpret the passed array of names based on the given LCID. This is the preferred solution because users would be able to write code in their national language and run the code on any localized version of the application.

At the very least, the application must check the LCID before interpreting member names. Also note that the meaning of parameters passed to a member function may depend on the caller's national language. For example, a spreadsheet application might interpret the arguments to a SetFormula method differently, depending on the LCID.