By now, we all have learned to call Control.InvokeRequired to avoid the following error when updating UI from another thread or calling other apartment threaded objects that expect to be called on a thread they were created on:

The calling thread cannot access this object because a different thread owns it.

In WPF though, the way to do same is as follows:

1. Instead of calling Control.InvokeRequired, call Control.CheckAccess
2. Use Control.Dispatcher.Invoke or BeginInvoke if CheckAccess returned false

Below is a simple example of doing just that:

using System;

using System.Windows;

namespace WPFWinApp

{

    public partial class Window1 : System.Windows.Window

    {       

        public Window1()

        {

            InitializeComponent();

        }

        void StartThread(object source, EventArgs e)

        {        

            System.Threading.ThreadPool.QueueUserWorkItem(new System.Threading.WaitCallback(DoWork));

        }

        void DoWork(object param)

        {

            try

            {

                if (base.CheckAccess() == true)

                    this.label1.Content = DateTime.Now.ToLongTimeString();

                else

                    base.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal,

                        new System.Threading.WaitCallback(DoWork), param);

            }

            catch (Exception ex)

            {

                System.Windows.MessageBox.Show(ex.Message);

                System.Diagnostics.Debug.WriteLine(ex.Message);

            }

        }

    }

}