Page 204 - DCAP408_WEB_PROGRAMMING

Windows Programming

Notes
Example: When your ‘small’ program grows into a very large one, it can also simplify
more immediate problems such as testing the code or making it work correctly in a concurrent
environment.

Self Assessment

Fill in the blanks:

6. A global variable can be get or set by any part of the program, and any .........................
regarding its use can be easily broken or forgotten.
7. If globals can be accessed by multiple threads of execution, ......................... is necessary
(and too-often neglected).
8. When dynamically linking modules, it can be unclear whether different libraries have
their own ......................... of globals or whether the globals are shared.
12.3 Exchanging Data with a Dialog Box – Pointer Method

Dialog Box Data Exchange and Validation

The controls in a dialog box are specialized windows that store their own copy of the data that
the user enters or changes. In the lifetime of a dialog box, you'll normally want to initialize
these controls with data from your program, and then save that data back into those variables.
You'll probably also want to validate the values stored in the controls to ensure that they are
within acceptable ranges when the user attempts to click OK to exit the dialog box.

Obviously, the first task in this process is to add new member variables to the dialog box
handler class that correspond to the controls.

Mapping Member Variables to Controls

You can use ClassWizard to add member variables and provide the mapping for most of the
dialog box controls via ClassWizard's Member Variables tab (see Figure 12.1).

Figure 12.1: The ClassWizard Member Variables Tab

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