Data Types For Visual Basic .NET Clients

Data types for the arguments and return values of the server functions are expressed as Automation data types, which are language-independent types defined by the Automation protocol.

For example, BSTR is a wide-character string type defined as an Automation type, and is the same data format used by the Visual Basic® language to store strings. Any COM-compliant controller should support these data types, although the details of how you declare and manipulate these are controller specific.