Tutorial 12 – Security Panel Application Introducing the Select Case Multiple-Selection Statement Outline 12.1 Test-Driving the Security Panel Application 12.2 Introducing the Select Case Multiple-Selection Statement 12.3 Constructing the Security Panel Application 12.4 Wrap-Up

In this tutorial, you will learn to: Objectives In this tutorial, you will learn to: Use the Select Case multiple-selection statement. Use Case statements. Use the Is keyword. Display a date and time. Use TextBox property PasswordChar.

12.1 Test-Driving the Security Panel Application

12.1 Test-Driving the Security Panel Application Load the Wage Calculator application Debug > Start

12.1 Test-Driving the Security Panel Application Figure 12.1　Security Panel application executing. TextBox Keypad Output ListBox

12.1 Test-Driving the Security Panel Application Figure 12.2　Asterisks displayed in Security code: field. An asterisk is displayed for each numeric key pressed

12.1 Test-Driving the Security Panel Application Entering invalid code Enter 1212 Click # Button

12.1 Test-Driving the Security Panel Application Figure 12.3　Security Panel displaying Access Denied message. Message indicating that an invalid security code was entered

12.1 Test-Driving the Security Panel Application Entering valid code Enter 1006 Click # Button

12.1 Test-Driving the Security Panel Application Figure 12.4　Security Panel application confirming a valid security-code entry. Message displayed when a valid security code is entered

12.2 Introducing the Select Case Multiple-Selection Statement Select Case statement Begins with keywords Select Case followed by test expression Can contain optional Case Else statement Terminates with keywords End Select

12.2 Introducing the Select Case Multiple-Selection Statement Figure 12.5　Select Case multiple-selection statement UML activity diagram.

12.3 Constructing the Security Panel Application

12.3 Constructing the Security Panel Application

12.3 Constructing the Security Panel Application Figure 12.7　Variable declarations for btnEnter_Click. Declaring event handler’s variables Declaring variables Clearing the TextBox

12.3 Constructing the Security Panel Application Creating Case statement Specify a range of values using: Keyword Is Comparison operator (in this case, <)

12.3 Constructing the Security Panel Application Figure 12.8　Select Case statement. Creating a Select Case statement Create Select Case statement Set controlling expression

12.3 Constructing the Security Panel Application Figure 12.9　First Case added to Select Case statement. Is keyword can be used for relational and equality comparisons

12.3 Constructing the Security Panel Application Creating a Case statement Specifying a range of values using: Keyword To Checking for a specific number Specifying multiple expressions Use a comma to separate expressions

12.3 Constructing the Security Panel Application Figure 12.10　Cases specified for remaining access codes. To keyword can be used to specify a range of values to test. Comma used to separate multiple expressions in a Case

12.3 Constructing the Security Panel Application Creating a Case Else statement Use keywords Case Else Must follow all other Case statements

12.3 Constructing the Security Panel Application Figure 12.11　Case Else of the Select Case statement. Case Else statement executes when no other case matches

12.3 Constructing the Security Panel Application Date structure Stores and displays date and time information Property Now returns: System time as a Date

12.3 Constructing the Security Panel Application Figure 12.12　Updating the Security Panel application’s ListBox.

12.3 Constructing the Security Panel Application Figure 12.13　Event handler btnZero_Click. Appending “0” to the end of a String

12.3 Constructing the Security Panel Application Figure 12.14　Event handlers btnOne_Click and btnTwo_Click. Appending “1” and “2” to the end of a String

12.3 Constructing the Security Panel Application Figure 12.15　Event handler btnClear_Click defined. Clearing the TextBox

Using a Select Case statement to determine user access level SecurityPanel.vb (1 of 5) Declaring variables Retrieving access code and clearing TextBox Using a Select Case statement to determine user access level

SecurityPanel.vb (2 of 5) Appending the numeric Button value to the text stored in the TextBox

SecurityPanel.vb (3 of 5)

SecurityPanel.vb (4 of 5)

SecurityPanel.vb (5 of 5) Clearing the TextBox