Adding programmatically an inline defined in XAML - wpf

Question

I have a FlowDocument. Is it possible to add an inline into it but the inline is defined in XAML. E.g.
<FlowDocument >
<Paragraph Name="Output"/>
</FlowDocument>
var AppendTo = new Span();
var XAML = "<Run>Something</Run>";
AppendTo.Inlines.Add(XAML); // This is what I mean - adding elements using XAML
Output.Inlines.Add(AppendTo);
Thank you
Note - to those who vote to close it because it's too broad. Maybe read the answer that I marked as answer and then think where the problem is.

Answer 1

You can create an actual Run element, or any other kind of element, from a XAML string programmatically using the XamlReader.Parse method:
var AppendTo = new Span();
var pc = new System.Windows.Markup.ParserContext();
pc.XmlnsDictionary.Add("", "http://schemas.microsoft.com/winfx/2006/xaml/presentation");
var run= System.Windows.Markup.XamlReader.Parse("<Run>Something</Run>", pc) as Run;
AppendTo.Inlines.Add(run);
Output.Inlines.Add(AppendTo);

Answer 2

Of course it's possible. It's easier when you assign a name to all relevant elements.
FlowDocument is defined as a resource of a Control
<Window.Resources>
<FlowDocument x:Key="Document">
<Paragraph Name="Inline" />
</FlowDocument>
</Window.Resources>
In the code-behind file of the Control you can use the FrameworkElement.TryFindResource(object) : object or FrameworkElement.FindResource(object) : object to sear through the control's resource:
private void OnLoaded(object sender, RoutedEventArgs e)
{
if (TryFindResource("Document") is FlowDocument document)
{
foreach (Block documentBlock in document.Blocks)
{
if (documentBlock is Paragraph paragraph || documentBlock.Name.Equals("Inline", StringComparison.OrdinalIgnoreCase))
{
// Do something with the Paragraph
}
}
}
}
FlowDocument is defined as element of the Control's visual tree
<Window>
<Grid SnapsToDevicePixels="True">
<RichTextBox>
<RichTextBox.Document>
<FlowDocument x:Name="Document">
<Paragraph Name="Inline" />
</FlowDocument>
</RichTextBox.Document>
</RichTextBox>
</Grid>
</Window>
In code-behind just access the elements by its name. Every element that has a Name value assigned is accessible via the auto-generated field reference:
private void OnLoaded(object sender, RoutedEventArgs e)
{
Paragraph paragraph = this.Inline;
// Do something with the Paragraph
}
The VisualTreeHelper can also be used to traverse the viaual tree and search for the document or inline element,