BackgroundWorker - 调用线程无法访问对象

So in my DoWork, I have

所以在我的DoWork中,我有

List<KeyValuePair<String, BitmapImage>> Files = new List<KeyValuePair<string,BitmapImage>>((List<KeyValuePair<String, BitmapImage>>)e.Argument);

foreach (KeyValuePair<String, BitmapImage> i in Files)
{
    string temp = i.ToString();               .......(1)
    //.....
}
Lis