Computer Programming Concepts and Visual Basic David I. Schneider

SUMMARY
1. The Visual Basic screen consists of a collection of objects for which various
properties can be set. Some examples of objects are text boxes, labels, command
buttons, picture boxes, and the form itself. Objects placed on the form are
called controls. Some useful properties are Text (set the text displayed by a text
box), Caption (set the title of a form, the contents of a label, or the words on a
command button), Font.Size (set the size of the characters displayed), Alignment
(set the placement of the contents of a label), MultiLine (text box to display
text on several lines), Picture (display drawing in picture box), ForeColor
(set foreground color), BackColor (set background color), Visible (show or hide
object), BorderStyle (alter and possibly remove border), Font.Bold (display
boldface text), and Font.Italic (display italic text).
2. An event procedure is called when a specific event occurs to a specified object.
Some event procedures are object_Click (object is clicked), object_LostFocus
(object loses the focus), object_GotFocus (object receives the focus), and
object_KeyPress (a key is pressed while object has the focus).
3. Visual Basic methods such as Print and Cls are applied to objects and are coded
as object.Print and object.Cls.
4. Two types of constants that can be stored and processed by computers are numbers
and strings.
5. The arithmetic operations are +, –, *, /, and ^. The only string operation is &,
concatenation. An expression is a combination of constants, variables, functions,
and operations that can be evaluated.
6. A variable is a name used to refer to data. Variable names can be up to 255 characters
long, must begin with a letter, and may contain letters, digits, and underscores.
Dim statements explicitly declare variables and specify the types of the
variables. In this book, variables have types Single, Integer, and String.
7. Values are assigned to variables by assignment and Input # statements. The values
appearing in assignment statements can be constants, variables, or expressions.
Input # statements look to data files for constants. String constants used
in assignment statements must be surrounded by quotation marks, whereas quotation
marks are optional for string constants input with Input #. InputBox can
be used to request that the user type in data.
8. The Print method displays information in a picture box or on the printer. Semicolons,
commas, and Tab control the placement of the items on a particular line.
A temporary message can be displayed on the screen using the MsgBox statement.
9. You control the printer with the Printer object and write to it with statements of
the form Printer.Print expression. You set properties with statements of the form
Printer.property = setting. Printer.NewPage starts a new page and PrintForm
does a screen dump. A series of commands to the Printer object must end with
EndDoc, which actually produces the final printed page.
10. Comment statements are used to explain formulas, state the purposes of variables,
and articulate the purposes of various parts of a program.
11. The Format functions provide detailed control of how numbers, dates, and
strings are displayed. Numbers can be made to line up uniformly and be displayed
with dollar signs, commas, and a specified number of decimal places.
Dates can be converted to a long form. Strings can be right-justified.
Programming Projects 67