Power BI

Content by Charles Sterling

Writing a Screen Saver in Visual Basic that displays Web Pages

The Team System Team just got a big beautiful 52" LCD for displaying Team news – Yeah! 

Unfortunately i was silly enough to volunteer to help put content on the computer driving this screen-boo!. 

Luckily Jeff mentioned an internal tool for displaying a list of websites in a Screen saver that should make my life much easier-yeah!

Unfortunately the silly utility doesn’t work in Vista and the creator didn’t include the source code-sigh. 

So after three hours of fighting with this tool ( pretty certain it is trying to write a temp file the UAC protected Windows directory) i and an internet search to see if there were projects on the internet for this (all the ones i found cost money (not a huge deal) and installed a bunch of junk i didnt want).  I decided to write my own…Since have never written a screen saver I thought it a good chance to play a little "on the clock"

Turns out to write a screen saver all that is need is to rename an application from *.exe to *.SCR and drop it into the Windows directory. 

To make it look like an screen saver all that is needed is to change a couple of properties:

Me.MaximizeBox = False
Me.MinimizeBox = False
Me.Text = ""
Me.TopMost = True
Me.WindowState = System.Windows.Forms.FormWindowState.Maximized

-Tada you have written a screen saver!

The code below reads a list of Web pages from a text file into an array…at some point i will probably enable the settings of my screen saver to set the filename and speed rotation into isolatedstorage for but for now i have just hard coded a path:


Imports Microsoft.VisualBasic.FileIO
Imports System.IO

Public Class Form1
Dim URLS(0) As String
Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load
Dim filename As String = "c:\devdiv\urllist2.txt"
Dim sr As StreamReader = New StreamReader(filename)
Dim line As String
If My.Computer.FileSystem.FileExists(filename) Then
‘ Create an instance of StreamReader to read from a file.
‘ Read and display the lines from the file until the end
‘ of the file is reached.
line = sr.ReadLine()
URLS(UBound(URLS)) = line
ReDim Preserve URLS(UBound(URLS) + 1)
Loop Until line Is Nothing
End If
End Sub

To enable my screen saver to display a webpage i used the built in Windows Form Web Browser control.  Finally to randomly change the web page i have used a timer control and the default code Snippet from Visual Studio for generating Random numbers. -Not bad for less time than i fought to debug a completed version.


Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
Dim generator As New Random
Dim randomValue As Integer
randomValue = generator.Next(0, UBound(URLS) – 1)
WebBrowser1.Url = New Uri(URLS(randomValue))
End Sub
End Class