Computer Programming Concepts and Visual Basic David I. Schneider

302 Computer Programming Concepts and Visual Basic
FIGURE 10-7 Several Effects Achieved with Shape Controls
THE LINE CONTROL
The Line control, which produces lines of various thickness, styles, and colors, is primarily used
to enhance the visual appearance of forms. The most useful properties of lines are BorderColor
(color of the line), BorderWidth (thickness of the line), BorderStyle (solid, dashed, dotted,
etc.), and Visible. Figure 10-8 shows several effects that can be achieved with lines. By convention,
names of line controls have the prefix lin.
FIGURE 10-8 Several Effects Achieved with Line Controls
THE IMAGE CONTROL
The image control is designed to hold pictures stored in graphics files such as .BMP files created
with Windows’ Paint, .ICO files of icons that come with Visual Basic, or .GIF and JPEG
images used on the World Wide Web. Pictures are placed in image controls with the Picture
property. If you double-click on the Picture property during design time, a file-selection dialog
box appears and assists you in selecting an appropriate file. However, prior to setting the
Picture property, you should set the Stretch property. If the Stretch property is set to False (the
default value), the image control will be resized to fit the picture. If the Stretch property is set
to True, the picture will be resized to fit the image control. Therefore, with Stretch property
True, pictures can be reduced (by placing them into a small image control) or enlarged (by placing
them into an image control bigger than the picture). Figure 10-9 shows a picture created
with Paint and reduced to several different sizes. By convention, names of image controls have
the prefix img.
A picture can be assigned to an image control at run time. However, a statement such as
imgBox.Picture = “filespec”
will not do the job. Instead, we must use the LoadPicture function in a statement such as
imgBox.Picture = LoadPicture(“filespec”)
Image controls enhance the visual appeal of programs. Also, because image controls respond
to the Click event and can receive the focus, they can serve as pictorial command buttons.