XamlReader.Load()的奇怪行为

解析外部XAML文件时遇到一个非常奇怪的问题。以前的历史是，我想加载一个外部XAML文件，其中包含要处理的内容。但我想加载尽可能多的不同文件。这是通过卸载旧的和装载新的来实现的。

我的问题是：当我第一次加载xaml时，一切都很好，一切都是应该的。但是当我第二次加载相同的xaml时，对象im Loading的每个条目都在那里两次。如果我再运行一次，每个对象都在那里三次，以此类推…

要自己调试项目，请在此处下载。该函数从文件"Control Panel.xaml.cs"的第137行开始。我真的不知道这是什么。是我的错还是只是一个错误？如果是，是否有解决方法？

    /// <summary>
    /// Load a xaml file and parse it
    /// </summary>
    public void LoadPresentation()
    {
        this.Title = "Control Panel - " + System.IO.Path.GetFileName(global.file);
        System.IO.FileStream XAML_file = new System.IO.FileStream(global.file, System.IO.FileMode.Open);
        try
        {
            System.IO.StreamReader reader = new System.IO.StreamReader(XAML_file);
            string dump = reader.ReadToEnd(); //This is only for debugging purposes because of the strange issue...
            XAML_file.Seek(0, System.IO.SeekOrigin.Begin);
            presentation = (ResourceDictionary)XamlReader.Load(XAML_file);
            //Keys the resourceDictionary must have to be valid
            if (presentation["INDEX"] == null || presentation["MAIN_GRID"] == null || presentation["CONTAINER"] == null || presentation["LAYOUTLIST"] == null)
            {
                throw new Exception();
            }
            //When this list is loaded, every item in it is there twice or three times or four... Why????
            TopicList Index = null;
            Index = (TopicList)presentation["INDEX"];
            for (int i = 0; i < topics.Count; )
            {
                topics.RemoveAt(i);
            }
            foreach (TopicListItem item in Index.Topics)
            {
                topics.Insert(item.TopicIndex, (Topic)presentation[item.ResourceKey]);
            }
            lv_topics.SelectedIndex = 0;
            selectedIndex = 0;
        }
        catch
        {
            System.Windows.Forms.MessageBox.Show("Failed to load XAML file '"" + global.file + "'"", "Parsing Error", System.Windows.Forms.MessageBoxButtons.OK, System.Windows.Forms.MessageBoxIcon.Error);
            presentation = null;
        }
        finally
        {
            XAML_file.Close();
        }
    }

编辑：

我试图序列化从XamlReader读取的对象，但输出中没有任何子元素。。。但如果我把这个对象从字典里拿出来，孩子们都在那里（重复和三次，但都在那里）。

我已经尝试通过清除列表

topics.Clear();

和

topics=new ObservableCollection<TopicListItem>();
lv_topics.ItemsSource=topics;

//When this list is loaded, every item in it is there twice or three times or four... Why???? 
TopicList Index = null; 
Index = (TopicList)presentation["INDEX"]; 
topics.Clear();
foreach (TopicListItem item in Index.Topics) 
{ 
    topics.Insert(item.TopicIndex, (Topic)presentation[item.ResourceKey]); 
} 
Index.Topics.Clear();        //Adding this will prevent the duplication
lv_topics.SelectedIndex = 0; 
selectedIndex = 0; 

    public void LoadPresentation()
    {
        ObservableCollection<TopicListItem> topics = new ObservableCollection<TopicListItem>() 

    public void LoadPresentation(string fileName)

    public ObservableCollection<TopicListItem> LoadPresentation(string fileName)