Question

This operation can only occur on the UI Thread.
can someone tell me how i can solve this issue in silverlight

mydll.classishere.givemestring((x) =>
            {
                System.Windows.Browser.HtmlPage.Window.Navigate(new Uri(x, UriKind.Relative), "_blank");

            });

Answer 1

Use this adjustment to flip the callback execution to the UI Thread:

mydll.classishere.givemestring((x) => 
{
     Deployment.Current.Dispatcher.BeginInvoke(() =>
     {
          System.Windows.Browser.HtmlPage.Window.Navigate(new Uri(x, UriKind.Relative), "_blank");  
     }
}