Teach Yourself Borland C++ in 14 Days - portal

314 Day 8
Summary
Today you have had a look into some of the basic components that C++Builder provides. You
have learned about components in general, and you have learned about some of the specifics
of the components that are based on Windows controls. It is important to understand the
basic controls available in Windows and the C++Builder components that represent those
controls. Today ends with an examination of the Windows common dialog boxes.
Workshop
The Workshop contains quiz questions to help you solidify your understanding of the
material covered and exercises to provide you with experience in using what you have learned.
You can find answers to the quiz questions in Appendix A, “Answers to Quiz Questions.”
Q&A
Q If I change the Name property of a component using the Object Inspector,
C++Builder will automatically change all references to that component in my
code, right?
A Yes and no. C++Builder will change all references to that component name in
C++Builder-generated code, but it will not change any user-written code.
Q The OpenDialog component is obviously a visible component. Why is it called a
nonvisual component?
A Because it is not visible at design time. It is visible only at runtime when you
invoke it with the Execute() method.
Q Why is it important to change the Name property only with the Object Inspector?
A As you work with the Form Designer, C++Builder writes code based on the Name
property. If you later change the Name property either by directly editing the source
files or at runtime, all references to that form or component will be incorrect and
will likely lead to your program refusing to compile or crashing at runtime.
Q I seem to be using properties more than methods when dealing with my
components in code. Is that wrong?
A Not at all. In fact, that’s the way VCL components are designed. A well-written
component makes maximum use of properties. For this reason you may not use a
component’s methods very often. Use methods when necessary, but otherwise use
properties to manipulate your components at runtime.