When I click my ActionButton, there is a timer that starts and after 3 seconds, it must fire a methode to change the current ContentPage to the another page. But i get a message : The calling thread cannot access this object because a different thread owns it. I dont understand what i am doing wrong. But if i put the ChangeContent() method in the click_event, it works, but in the _tm_elapsed it doenst work?
using smartHome2011.FramePages;
using System.Timers;
public partial class AuthenticationPage : UserControl
{
private MainWindow _main;
private Storyboard _storyboard;
private Timer _tm = new Timer();
private HomeScreen _homeScreen = new HomeScreen();
public AuthenticationPage(MainWindow mainP)
{
this.InitializeComponent();
_main = mainP;
}
private void ActionButton_Click(object sender, System.EventArgs eventArgs)
{
_main.TakePicture();
identifyBox.Source = _main.source.Clone();
scanningLabel.Visibility = Visibility.Visible;
_storyboard = (Storyboard) FindResource("scanningSB");
//_storyboard.Begin();
Start();
}
private void Start()
{
_tm = new Timer(3000);
_tm.Elapsed += new ElapsedEventHandler(_tm_Elapsed);
_tm.Enabled = true;
}
private void _tm_Elapsed(object sender, ElapsedEventArgs e)
{
((Timer) sender).Enabled = false;
ChangeContent();
//MessageBox.Show("ok");
}
private void ChangeContent()
{
_main.ContentPage.Children.Clear();
_main.ContentPage.Children.Add(_homeScreen);
}
}
You have to use Invoke to ensure that the UI Thread (the thread who has created your Control) will execute that.
private void ChangeContent()
{
if (this.InvokeRequired)
{
this.Invoke(new MethodInvoker(ChangeContent));
return;
}
_main.ContentPage.Children.Clear();
_main.ContentPage.Children.Add(_homeScreen);
}
private void _tm_Elapsed(object sender, ElapsedEventArgs e)
{
((Timer) sender).Enabled = false;
this.Dispatcher.Invoke(new Action(ChangeContent), null);
//MessageBox.Show("ok");
}