WPF Cross thread operation - Forum

navraj

2010-12-12, 06:59 #1

Member since Dec 2010 · 9 posts
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Subject: WPF Cross thread operation

hello all,

i am creating a messenger application in WPF and i am able to login into Openfire server with both agsxmpp and matrix. i created a login screen with user name and password button and a login and cancel button.
when it successfully logs in i want to make the cancel and login button invisible but it does not happen and says the calling thread cannot access this object because a different thread owns it.

i have tried using dispatcher but WPF does not have an invoke required function

here is the code

   Private Sub SignIn_Click(ByVal sender As System.Object, ByVal e As System.Windows.RoutedEventArgs) Handles SignIn.Click
      Dim jid As New Jid(txtID.Text)
      xmppCon.Password = txtPassword.Password
      xmppCon.Username = jid.User
      xmppCon.Server = jid.Server
      xmppCon.AutoAgents = False
      xmppCon.AutoPresence = True
      xmppCon.AutoRoster = True
      xmppCon.AutoResolveConnectServer = True

      Try
      xmppCon.Open()

      Catch ex As Exception
      Debug.WriteLine(ex.Message)

      End Try

    End Sub

    Private Sub xmppCon_OnLogin(ByVal sender As Object) Handles xmppCon.OnLogin
      Dim ob(0) As Object
      ob(0) = sender
      Cancel.Dispatcher.BeginInvoke(CType(AddressOf xmppCon_OnLogin, agsXMPP.ObjectHandler), ob)
Cancel.Visibility = Windows.Visibility.Hidden

      Debug.Write("lOGGED iN")

    End Sub

can somebody give me an idea how it gets done in WPF?

Alex

2010-12-12, 11:45 #2

Member since Feb 2003 · 4449 posts · Location: Germany
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When you set a reference to your Ui in the Dispatcher property then MatriX handles all the dispathing for you automatically.
I use rhe following code in my WPF apps:

xmppClient.Dispatcher = this.Dispatcher;

Quote by navraj:
i have tried using dispatcher but WPF does not have an invoke required function

it's Dispatcher.CheckAccess() in WPF. But you don't need it because MatriX does the job for you.

Alex