Teach Yourself Borland C++ in 14 Days - portal

308 Day 8
■ Font
■ Color
■ Print
■ Printer Setup
■ Find
■ Replace
The common dialog boxes are found on the Dialogs tab of the Component Palette. These
components are nonvisual because they do not have a visual design-time interface. The
following sections discuss each of these dialog boxes with one exception—I’ll leave the
discussion of the Print and Printer Setup dialog boxes for later, when I discuss printing.
The Execute Method
NOTE
One thing that all the common dialog boxes have in common is the Execute() method, which
is used to create and display the dialog box. The dialog box is displayed modally except for
the Find and Replace dialog boxes, which are displayed modelessly. Execute() returns true
if the user clicked the OK button, double-clicked a file name, or pressed Enter on the
keyboard. Execute() returns false if the user clicked the Cancel button, pressed the Esc key,
or closed the dialog box with the system close box. A common dialog box is often
implemented like this:
if (OpenDialog->Execute()) {
// user pressed OK so use the filename
Memo->Lines->LoadFromFile(OpenDialog->FileName);
}
return;
This code displays the File Open dialog box and gets a filename from the user. If the user
clicked the OK button, the code inside the if block is executed and the file is loaded in to
a Memo component. If OK was not pressed, the code inside the if block is ignored and no
action takes place.
The code used in the previous snippet is another example of C++
shortcut syntax. The first line:
if (OpenDialog->Execute()) {
is equivalent to this:
if (OpenDialog->Execute() == true) {
Use either method, but the first is preferred.