如何将XAML插入RichTextBox？

存储在数据库中的XAML文本，通过XmlReader读取XAML后如何在RichTextBox中显示其文本？

StringReader stringReader = new StringReader(xamlString);
XmlReader xmlReader = XmlReader.Create(stringReader);

rt.文档 = ???

- - - 更新 - - - - - - - - - - 这是 xamlString 内容：

<Section xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xml:space="preserve" TextAlignment="Left" LineHeight="Auto" IsHyphenationEnabled="False" xml:lang="en-us" FlowDirection="RightToLeft" NumberSubstitution.CultureSource="User" NumberSubstitution.Substitution="AsCulture" FontFamily="Tahoma" FontStyle="Normal" FontWeight="Normal" FontStretch="Normal" FontSize="13" Foreground="#FF000000" Typography.StandardLigatures="True" Typography.ContextualLigatures="True" Typography.DiscretionaryLigatures="False" Typography.HistoricalLigatures="False" Typography.AnnotationAlternates="0" Typography.ContextualAlternates="True" Typography.HistoricalForms="False" Typography.Kerning="True" Typography.CapitalSpacing="False" Typography.CaseSensitiveForms="False" Typography.StylisticSet1="False" Typography.StylisticSet2="False" Typography.StylisticSet3="False" Typography.StylisticSet4="False" Typography.StylisticSet5="False" Typography.StylisticSet6="False" Typography.StylisticSet7="False" Typography.StylisticSet8="False" Typography.StylisticSet9="False" Typography.StylisticSet10="False" Typography.StylisticSet11="False" Typography.StylisticSet12="False" Typography.StylisticSet13="False" Typography.StylisticSet14="False" Typography.StylisticSet15="False" Typography.StylisticSet16="False" Typography.StylisticSet17="False" Typography.StylisticSet18="False" Typography.StylisticSet19="False" Typography.StylisticSet20="False" Typography.Fraction="Normal" Typography.SlashedZero="False" Typography.MathematicalGreek="False" Typography.EastAsianExpertForms="False" Typography.Variants="Normal" Typography.Capitals="Normal" Typography.NumeralStyle="Normal" Typography.NumeralAlignment="Normal" Typography.EastAsianWidths="Normal" Typography.EastAsianLanguage="Normal" Typography.StandardSwashes="0" Typography.ContextualSwashes="0" Typography.StylisticAlternates="0"><Paragraph><Run xml:lang="fa-ir">Hello</Run><Run xml:lang="fa-ir" FontStyle="Italic">Hello1</Run><Run xml:lang="fa-ir" FontWeight="Bold">Testing</Run><Run xml:lang="fa-ir">Testing2</Run></Paragraph></Section>

从 RichTextBox 检索 XAML 文本：

private static string GetRTF(RichTextBox rt)
{
    TextRange range = new TextRange(rt.Document.ContentStart, rt.Document.ContentEnd);
    MemoryStream stream = new MemoryStream();
    range.Save(stream, DataFormats.Xaml);
    string xamlText = Encoding.UTF8.GetString(stream.ToArray());
    return xamlText;
}

将 XAML 文本渲染到 RichTextBox 中：

private static FlowDocument SetRTF(string xamlString)
{
    StringReader stringReader = new StringReader(xamlString);
    XmlReader xmlReader = XmlReader.Create(stringReader);
    Section sec = XamlReader.Load(xmlReader) as Section;
    FlowDocument doc = new FlowDocument();
    while (sec.Blocks.Count > 0)
        doc.Blocks.Add(sec.Blocks.FirstBlock);
    return doc;
}