Computer Programming Concepts and Visual Basic David I. Schneider

26 Computer Programming Concepts and Visual Basic
COMMENTS
1. When selecting from a list, double-clicking has the same effect as clicking once
and pressing Enter.
2. On a form, the Tab key cycles through the objects that can get the focus, and in
a dialog box, it cycles through the items.
3. The form itself is also an object and has properties. For instance, you can
change the text in the title bar with the Caption property. You can move the form
by dragging the title bar of its Project Container window.
4. The name of an object is used in code to refer to the object. By default, objects
are given names like Text1 and Text2. You can use the Properties window to
change the Name property of an object to a more suggestive name. (The Name
property is always the first property in the list of properties. An object’s Name
must start with a letter and can be a maximum of 40 characters. It can include
numbers and underline (_) characters, but can’t include punctuation or spaces.)
Also, Microsoft recommends that each name begin with a three-letter prefix
that identifies the type of the control. See the table below. Beginning with Section
2.2, we will use suggestive names and these prefixes whenever possible.
Object Prefix Example
command button cmd cmdComputeTotal
form frm frmPayroll
label lbl blInstructions
picture box pic picClouds
text box txt txtAddress
5. The Name and Caption properties of a command button are both initially set to
something like Command1. However, changing one of these properties does not
affect the setting of the other property. Similarly for the Name and Caption
properties of forms and labels, and for the Name and Text properties of text
boxes.
6. The color settings appear as strings of digits and letters preceded by &H and
trailed with &. Don’t concern yourself with the notation.
7. Here are some fine points on the use of the Properties window.
(a) Press Shift+Ctrl+letterkey to highlight the first property that begins with
that letter. Successive pressings highlight successive properties that begin
with that letter.
(b) To change the selected object from the Properties window, click on the
down-arrow icon at the right of the Object box of the Properties window.
Then select the new object from the drop-down list.
8. Some useful properties that have not been discussed are the following:
(a) BorderStyle: Setting the BorderStyle to “0 – None” removes the border
from an object.
(b) Visible: Setting the Visible property to False hides an object when the program
is run. The object can be made to reappear with code.
(c) BackColor: Specifies the background color for a text box, label, picture
box, or form. Also specifies the background color for a command button
having the Style property set to “1 – Graphical.” (Such a command button
can display a picture.)
(d) BackStyle: The BackStyle property of a label is opaque by default. The rectangular
region associated with the label is filled with the label’s back-