Microsoft Visual Basic 2010 Step by Step eBook

Chapter 6 Using Decision Structures 179

Chapter 6 Quick Reference

To Do This

Write a conditional

expression

Use one of the following comparison operators

between two values: =, <>, >, <, >=, or <=.

Use an If... Then

decision structure

Use the following syntax:

If condition1 Then

statements executed if condition1 True

ElseIf condition2 Then

statements executed if condition2 True

Else

statements executed if none are True

End If

Receive input from the

user in a specific format

Add a MaskedTextBox control to your form, and specify the input

format by configuring the Mask property.

Use a Select Case

decision structure

Use the following syntax:

Select Case variable

Case value1

statements executed if value1 matches

Case value2

statements executed if value2 matches

Case Else

statements executed if none match

End Select

Rename an object in

a program

Select the object that you want to rename, and then modify the

object’s (Name) property by using the Properties window. If you

give the object a three-character prefix that identifies its object

type (btn, lbl, lst, etc .), the object is easier to spot in program code.

Make two comparisons in

a conditional expression

Use a logical operator between comparisons (And, Or, Not, or Xor).

Short-circuit an If... Then

statement

If... Then statements can be short-circuited when the AndAlso and

OrElse operators are used and two or more conditional expressions

are given. Depending on the result of the first condition, Visual Basic

might not evaluate the additional conditions, and the statement is

short-circuited.

Write an event handler In the Code Editor, click an object name in the Class Name list box,

and then click an event name in the Method Name list box. Add

program statements to the event procedure (called an event handler)

that respond to the event you are customizing.