WPFで別スレッドでの処理
Task.Factory.StartNew(() =>
{
Dispatcher.Invoke(new Action(() =>
{
// 別スレッドの処理
textBoxResult.Text = "this is a pen.";
}));
});

Sample code collection
Task.Factory.StartNew(() =>
{
Dispatcher.Invoke(new Action(() =>
{
// 別スレッドの処理
textBoxResult.Text = "this is a pen.";
}));
});