1. VBScript
Session 4
Dani Vainstein

2. What we learn last session?
Constants
VBScript operators.
Working with Logical, arithmetic and comparision operators.
Dani Vainstein

3. Subjects for session 4 Conditional statements. If…Then…Else
Select Case
Dani Vainstein

4. Conditional Statements
You can control the flow of your script with conditional statements and looping statements.
Using conditional statements, you can write VBScript code that makes decisions and repeats actions.
The following conditional statements are available in VBScript:
If...Then...Else statement
Select Case statement
Dani Vainstein

5. If Then Else
Dani Vainstein

6. Making Decisions Using If...Then...Else
The If...Then...Else statement is used to evaluate whether a condition is True or False and, depending on the result, to specify one or more statements to run.
Usually the condition is an expression that uses a comparison operator to compare one value or variable with another.
If...Then...Else statements can be nested to as many levels as you need.
Dani Vainstein

7. Making Decisions Using If...Then...Else
To run only one statement when a condition is True, use the single-line syntax for the If...Then...Else statement.
The following example shows the single-line syntax. Notice that this example omits the Else keyword.
Dim myDate myDate = #2/13/95# If myDate < Now Then myDate = Now
To run more than one line of code, you must use the multiple-line (or block) syntax.
If value = 0 Then AlertLabel.ForeColor = vbRed AlertLabel.Font.Bold = True AlertLabel.Font.Italic = True End If
Dani Vainstein

8. Making Decisions Using If...Then...Else
Running certain statements if a condition is true and Running others if a condition is false
You can use an If...Then...Else statement to define two blocks of executable statements:
one block to run if the condition is True, the other block to run if the condition is False.
If value = 0 Then
AlertLabel.ForeColor = vbRed
AlertLabel.Font.Bold = True
AlertLabel.Font.Italic = True
Else
AlertLabel.Forecolor = vbBlack
AlertLabel.Font.Bold = False
AlertLabel.Font.Italic = False
End If
Dani Vainstein

9. Making Decisions Using If...Then...Else
Deciding Between Several Alternatives
A variation on the If...Then...Else statement allows you to choose from several alternatives.
Adding ElseIf clauses expands the functionality of the If...Then...Else statement so you can control program flow based on different possibilities.
If value = 0
Then Message = “zero”
ElseIf value = 1 then
Message = “one”
ElseIf value = 2 then
Message = “two”
Else
Message = "Value out of range!"
End If
Dani Vainstein

10. Making Decisions Using If...Then...Else
You can add as many ElseIf clauses as you need to provide alternative choices.
Extensive use of the ElseIf clauses often becomes cumbersome.
A better way to choose between several alternatives is the Select Case statement.
Dani Vainstein

11. Select Case
Dani Vainstein

12. Making Decisions with Select Case
Executes one of several groups of statements, depending on the value of an expression.
The Select Case structure provides an alternative to If...Then...ElseIf for selectively executing one block of statements from among multiple blocks of statements.
A Select Case statement provides capability similar to the If...Then...Else statement, but it makes code more efficient and readable.
Dani Vainstein

13. Making Decisions with Select Case
A Select Case structure works with a single test expression that is evaluated once, at the top of the structure.
The result of the expression is then compared with the values for each Case in the structure.
If there is a match, the block of statements associated with that Case is executed
Dani Vainstein

14. Making Decisions with Select Case
Select Case strCreditCard
Case "MasterCard"
DisplayMCLogo
ValidateMCAccount
Case "Visa"
DisplayVisaLogo
ValidateVisaAccount
Case "American Express"
DisplayAMEXCOLogo
ValidateAMEXCOAccount
Case Else
DisplayUnknownImage
PromptAgain
End Select
Dani Vainstein

15. Making Decisions with Select Case
If testexpression matches any Case expressionlist expression, the statements following that Case clause are executed up to the next Case clause, or for the last clause, up to End Select.
Control then passes to the statement following End Select.
If testexpression matches an expressionlist expression in more than one Case clause, only the statements following the first match are executed.
Dani Vainstein

16. Making Decisions with Select Case
The Case Else clause is used to indicate the elsestatements to be executed if no match is found between the testexpression and an expressionlist in any of the other Case selections.
Although not required, it is a good idea to have a Case Else statement in your Select Case block to handle unforeseen testexpression values.
Select Case statements can be nested. Each nested Select Case statement must have a matching End Select statement.
Dani Vainstein

17. Lab 4.1
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18. Lab 4.1 Write a small program: Declare a constant PASSWORD
Declare two variables strPsw and Name.
If the password is OK, Wellcome the user in the reporter (micPass)
Else , display a message in the Reporter (micFail)
Use the If…Then…Else Statement
Dani Vainstein

19. Lab 4.2 Write a small program: Declare a variable iNumber
Display in the reporter the name of the number (“one”, “two”)
If the number is not between 0 and 10 display a message “out of range”
Use the select Case statement.
Dani Vainstein

20. Lab 4.3 Write a small program: Declare a variable iNumber, bSign
Like in 4.2, but a number can be from -10 to 10
Display in words, the value of the number i.e. for -2 (Minus two), and for 4 (Plus Four)
Otherwise display a message out of range
Use if..then…End If statement once and Select Case once.
Dani Vainstein

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