Subclassing and Hooking with Visual Basic

NuMega’s SmartCheck

I have not mentioned this tool much, although I use it frequently. SmartCheck provides debug information about a VB application during runtime. This tool is invaluable in debugging application crashes, erroneous application programming interface (API) calls, and much more. You can set up this tool as an add-in to VB, and it is fairly intuitive to use.

Besides pointing out application errors, SmartCheck also displays API functions, function parameters, return values, and even the data to which a pointer points. This is very useful when determining if the string data or a structure pointed to by a pointer contains the correct information. Figure 8-1 displays a screenshot of SmartCheck.

Figure 8-1. Screenshot of the SmartCheck debugging tool

To illustrate what type of information SmartCheck provides you with and what a VB subclassing application looks like on the inside, I will step through the output of a previous example application. The example application I will examine is the Minimize button subclassing example of Chapter 4. Figure 8-2 shows a screenshot of this application.

Figure 8-2. The Minimize subclassing example application of Chapter 4

I will run this application under SmartCheck, subclass the Minimize button, remove the subclassing, and then shut down ...