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using System;

using System.Windows;

using System.Windows.Threading;

namespace Sheva.Windows

{

    /// <summary>

    /// Designates a Windows Presentation Foundation application model with added functionalities.

    /// </summary>

    public class WpfApplication : Application

    {

        private static DispatcherOperationCallback exitFrameCallback = new

                                DispatcherOperationCallback(ExitFrame);

        /// <summary>

        /// Processes all UI messages currently in the message queue.

        /// </summary>

        public static void DoEvents()

        {

            // Create new nested message pump.

            DispatcherFrame nestedFrame = new DispatcherFrame();

            // Dispatch a callback to the current message queue, when getting called,

            // this callback will end the nested message loop.

            // note that the priority of this callback should be lower than the that of UI event messages.

            DispatcherOperation exitOperation = Dispatcher.CurrentDispatcher.BeginInvoke(

                                                  DispatcherPriority.Background, exitFrameCallback, nestedFrame);

            // pump the nested message loop, the nested message loop will

            // immediately process the messages left inside the message queue.

            Dispatcher.PushFrame(nestedFrame);

            // If the "exitFrame" callback doesn't get finished, Abort it.

            if (exitOperation.Status != DispatcherOperationStatus.Completed)

            {

                exitOperation.Abort();

            }

        }

        private static Object ExitFrame(Object state)

        {

            DispatcherFrame frame = state as DispatcherFrame;

            // Exit the nested message loop.

            frame.Continue = false;

            return null;

        }

    }

}