How to show loading dialog in phonegap in windows phone using plugins?

Question

I am developing an phonegap application i just try to show a circular progress dialog while loading a page, i achieved this in android usingphonegap plugins, when i try to show a Message box from windows native in phonegap using plugin it tells that 'Invalid cross-thread access.'

here is my code

     using System;
     using System.Collections.Generic;
     using System.Linq;
     using System.Text;
     using Microsoft.Phone.Shell;
     using System.Windows;

     namespace WPCordovaClassLib.Cordova.Commands
     {
          public class Echo : BaseCommand
          {
              public void echo(string options)
              {
                  MessageBox.Show("Are you sure?", "Delete Item", MessageBoxButton.OKCancel);

              }
          }
      }

my screen shot

My javascript call

    cordova.exec( function(){}, function(){}, "Echo","echo", ["input string"]);

Answer 1

The callback is probably not on the ui thread, it's probably why you get this error just dispatching it back to the ui thread should solve the problem:

public void echo(string options)
{
    Deployment.Current.Dispatcher.BeginInvoke(() =>
        {
              MessageBox.Show("Are you sure?", "Delete Item", MessageBoxButton.OKCancel);
        });
}