Visual Basic

Microsoft Active Accessibility

Active Accessibility is an architecture developed by Microsoft designed to make software more accessible. So far all the methods we've discussed have dealt only with Windows system settings and functions. Active Accessibility provides a whole new set of function calls and interfaces to enable you to create applications that developers of accessibility aids, such as screen readers, can interface with.

That's the good news. The bad news is that Active Accessibility is still a relatively new architecture. As of this writing, Active Accessibility is still on version 1.1. This version has a number of limitations, the first of which is that it's not available on Windows NT 4. If you're developing with Windows 9x, you can install the SDK and implement the functions and procedures in your development project. However, the Active Accessibility SDK will not install under Windows NT 4.

Now for the next problem: Active Accessibility-the SDK and all the documentation-were designed for C++. The SDK comes with a sample Visual Basic 4 program that does run under Visual Basic 6. The SDK also comes with a type library that you can import into your Visual Basic project. The problem with the type library is that the function calls tend to differ slightly from those in the C++ documentation, and they don't come with any documentation of their own.

So, that said, we're going to make do with what we have and get as much out of this technology as possible in preparation for the improvements Microsoft's Active Accessibility group will make in the future. We'll walk through a sample program, AAccess (shown in Figure 16-6), that demonstrates how to use some of the object retrieval calls and shows what kind of accessible object information is available.

Figure 16-6 Active Accessibility sample program