ADO: ActiveX Data Objects

Accessing ADO with Visual C++

Visual C++ is a much more difficult language and environment with which to develop applications for ActiveX Data Objects. Because it is so difficult, Microsoft is constantly trying to provide developers with easier ways to access ADO components.

By far the easiest method (and the only method described here) is one that takes advantage of the #import keyword. This approach offers not only the most control to the developer, but it also allows the developer to code in a Visual Basic programming style.

Referencing ActiveX Data Objects

The #import keyword is used in Visual C++ applications to import information from a type library. To make ADO.ACcessible to your C++ code, use the following #import directive:

#import <msado15.dll> no_namespace rename("EOF", "EOFile")

This statement assumes that the path to msado15.dll (usually C:\Program Files\Common Files\System\ADO) is already set within the Visual C++ environment; if not, select the Directories tab of the Options dialog box (Tools → Options), and add it.

The #import statement does a couple of things. First, at compile time it creates a header file with a .tlh extension, which stands for Type Library Header. This header file is comprised of enumerated types and definitions for the objects contained in the type library for msado15.dll.

Secondly, it creates a file with a .tli (Type Library Implementation) extension that contains the wrappers for each function in the object model defined by the msado15.dll ...