c# – 在windows phone中使用richtextbox的事情

html源代码如下：

Paragraph1</p>
<img src="http://www.ifanr.com/wp-content/uploads/2011/11/DSC_332401.jpg" alt="" width="600" height="338" /></p>
Paragraph2.</p>
<h3>Title h3</h3>
Paragraph3.
</p>

然后我用了

"string[] sArray = Regex.Split(html,"</p>",RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);"

将它们分成一个数组.最后,我使用代码：

foreach (string array in sArray)
            {
                Paragraph parag = new Paragraph();
                Run run = new Run();
                Bold bold = new Bold();
                if (!Regex.IsMatch(array.ToString(),@"<imgb[^<>]*?bsrcs*=s*[""']?s*(?<imgUrl>[^s""'<>]*)[^<>]*?/?s*>"))
                {
                    //h3
                    if (array.ToString().Contains("</h3>"))
                    {
                        string hString = array.ToString();
                        hString = Regex.Replace(hString,"<h3>","");
                        string[] hArray = Regex.Split(hString,"</h3>",RegexOptions.IgnoreCase | RegexOptions.IgnorePatternWhitespace);
                        bold.Inlines.Add(hArray[0].ToString());
                        parag.Inlines.Add(bold);
                        run.Text = hArray[1].ToString();
                        parag.Inlines.Add(run);
                    }
                    else
                    {
                        if(array.ToString().Contains("<blockquote>"))
                        {
                            run.Text = Regex.Replace(array.ToString(),"<blockquote>","blockquote:");
                            run.FontSize = 18;
                        }
                        else
                            run.Text = array.ToString();
                        parag.Inlines.Add(run);
                    }
                    rtb.Blocks.Add(parag);
                }
                else
                {
                    //insert the image into richtextbox
                    Regex regImg = new Regex(@"http://[^[^>]*?(gif|jpg|png|jpeg|bmp|bmp)",RegexOptions.IgnoreCase);
                    MatchCollection matches = regImg.Matches(array.ToString());
                    string result = null;
                    foreach (Match match in matches)
                        result = match.Value;

                    Image image = new Image();

                    image.Stretch = Stretch.Uniform;
                    image.Source = new BitmapImage(new Uri(result,UriKind.RelativeOrAbsolute));
                    InlineUIContainer iuc = new InlineUIContainer();
                    iuc.Child = image;
                    parag.Inlines.Add(iuc);
                    rtb.Blocks.Add(parag);
                }

要将一些段落或图像添加到richtextbox中,一切进展顺利,但是当我向下滚动richtextbox时,其余段落消失.它整天困扰我,因为我无法找出richtextbox的错误.
这只是Windows手机中的一个错误吗？有什么想法吗？

ScreenShot1：

ScreenShot2：

p.s：html源代码是否包含一些非英文字符并不重要.当html源代码包含大量单词时会发生这种情况.这两个ScreenShot只显示了这个问题.