The new features let developers create so-called apartment-model-threading ActiveX controls that can be embedded into applications to let users open multiple browser windows, in the company's Internet Explorer 4.0 Web browser for instance, without a performance hit, according to Visual Basic product managers.
"You might have a stock ticker, PointCast, and several Web sites open in IE 4.0, with many ActiveX components and Web sites running simultaneously on your desktop through multiple instances of IE. Apartment-model controls lets each instance of IE run without performance degradation," said Lane Sorgen, a VB product manager.
Multithreading is a feature supported by both Windows NT and Windows 95, which allows many operations to be performed at one time. Apartment threading refers to the multithreading of multiple operations and controls within a single application, such as a Web browser.
Currently, Visual Basic can only create single-threaded controls. Developers have in the past used tools such as Microsoft's Visual C++ or other C++ compilers to build apartment-model controls, said Sorgen.
"Threading is very powerful, but developers needed to understand low-level OS management. Now it's built it into compiler, so all you have to do is click and [Visual Basic] takes care of it," said Sorgen.
The apartment-model support is incorporated into both a new version of the free Control Creation Edition, and a Service Pack for users of Visual Basic 5.0. Both can be downloaded from Microsoft's Web site.
Developers can use either version to create new multithreaded controls, and to recompile existing controls, according to Microsoft.