Task.Factory.StartNew(
                delegate
                {
                    TimeConsumingTask();
                }
                );

            Task.Factory.StartNew(
                () =>
                {
                    TimeConsumingTask();
                }
            );
            Task.Run(
                () =>
                {
                    TimeConsumingTask2();

                });

            ThreadPool.QueueUserWorkItem(o =>
            {
                TimeConsumingTask2();
            });

            this.label1.Invoke((MethodInvoker)delegate
            {
                this.label1.Text = "Time is UP";
            });

先在UI线程中
dispatcher = Dispatcher.CurrentDispatcher;
在工作线程中

            dispatcher.Invoke(() =>
                {
                    this.label1.Text = "Time is UP2";

                });