Visual Basic.NET How to Program (PDF)

Chapter 20 ASP .NET, Web Forms and Web Controls 997
21 ' determine if Session contains information
22 If Session.Count 0 Then
23
24 ' iterate through Session values,
25 ' display in ListBox
26 For i = 0 To Session.Count - 1
27
28 ' store current key in sessionName
29 keyName = Session.Keys(i)
30
31 ' use current key to display
32 ' Session's name/value pairs
33 booksListBox.Items.Add(keyName & _
34 " How to Program. ISBN#: " & _
35 Session(keyName))
36 Next
37 Else
38 recommendationLabel.Text = "No Recommendations"
39 booksListBox.Visible = False
40 End If
41 End Sub ' Page_Init
42
43 Private Sub Page_Load(ByVal sender As System.Object, _
44 ByVal e As System.EventArgs) Handles MyBase.Load
45
46 ' Put user code to initialize the page here
47 End Sub ' Page_Load
48 End Class ' Recommendations
Fig. 20.33 Session data read by an ASP .NET Web application to provide
recommendations for the user (part 2 of 2).
Event handler Page_Init (lines 13–41) retrieves the session information. If a user
has not selected any language during any visit to this site, our Session object’s Count
property will be zero. This property provides the number of session items contained in a
Session object. If Session object’s Count property is zero (i.e., no language was ever
selected) then we display the text No Recommendations.