How does one wait for amount of time

[Jim Bassett]

I have a .net 4.0 VB WPF application where websites, PDF files, pictures, and such are selected via buttons to be displayed. I am trying to set up a feature that rotates thru those web sites, PDF, files pictures, etc. staying on each one maybe 1 miniute or 5 minutes. While it is staying on a specific site a user might select a button which would then jump out of the wait and go to that site, picture or file. I do not know how to do this can someone give me a hint, or existing code or example?

Thank you

[dglienna]

Post some code. Each IMAGE should be able to be rotated

[Jim Bassett]

Sorry I wasn't meaning rotate the web site, file, or PDF I was meaning go to a web site and stay there for x number of minutes and then go to another site, or file or PDF, etc. Let me explain futher the WPF application has a web browser control in it. When the application starts it points to a specific web site and remains there until someone clicks one of the various buttons on the WPF application window to go to another URL or PDF. I want to add the feature that when the applications starts it shows a specific web page like it does now and after x number of minutes it goes to another site or a PDF file just as if someone had click one of the buttons. Someone would still be able to click one of the various buttons to go to a site of file rather than wait for the rotating loop to take them there.

[DataMiser]

You could use a timer, assuming they are available in WPF apps.

[GremlinSA]

You could use a timer, assuming they are available in WPF apps.

Yes they are...

    Private timer As System.Windows.Threading.DispatcherTimer

    Private Sub Window1_Loaded(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles MyBase.Loaded
        timer = New System.Windows.Threading.DispatcherTimer()
        timer.Interval = TimeSpan.FromMilliseconds(100)
        AddHandler timer.Tick, AddressOf timer_Tick
        Me.timer.Start()

    End Sub

    Sub timer_Tick(ByVal sender As Object, ByVal e As EventArgs)
        'This sub will be called ~ every 100ms
    End Sub

In the tick event you can implement a countdown and select the next target..

[Jim Bassett]

Timer will work except I get an exception about object belonging to an existing thread. This is a WPF applicaton written in VB.NET with a Web Browser control in it. Here is a shorted version of the code being used from the main window class:

Public Sub New()

' This call is required by the designer.
InitializeComponent()

' Setup Timer
objTimer = New Timer(5000)
AddHandler objTimer.Elapsed, New ElapsedEventHandler(AddressOf rotateHandler)


'Set default URI to navigate to CNN News
' Go to the default web page by calling Navigate method
Me.WebBrowser1.Navigate(("http://www.cnn.com/"))

' Set rotate value to -1 to refer to first URL. roate value will be
' incremented in timer handler. A value of 0 will refer to first URL
iRotateValue = -1

' Enable the Time
objTimer.Enabled = True

End Sub

' Rotate Handler
Public Sub rotateHandler(ByVal sender As Object, ByVal e As ElapsedEventArgs)

' Increment the rotate index
iRotateValue = iRotateValue + 1

' Use case statement to select next URL to go to
Select Case iRotateValue

Case 0

' Go to the beginning web page by calling Navigate method
Me.WebBrowser1.Navigate(("http://www.cnn.com/"))


Case 1
' Fox News
' Go to the Fox News web page by calling Navigate method
Me.WebBrowser1.Navigate(("http://video.foxnews.com/"))

Case 2

' Weather Channel
' Go to the Waether Channel web page by calling Navigate method
Me.WebBrowser1.Navigate((""http://www.weather.com/weather/today/Fort+Worth+TX+76102"))

' Reset roate value to -1 so as to start again with CNN at the next timer handling
iRotateValue = -1

End Select

End sub

The first time the handler is called it fails on the I get an erorr saying "The calling thread cannot access this object because a different thread owns it." on the Fox news naviation line in Case one " Me.WebBrowser1.Navigate(("http://video.foxnews.com/")) "

I am not how to construct this.

[Jim Bassett]

Thank you GremlinSA and everyone else. The DispatchTimer did the trick!!!!!