Copying one FlowDocument to Second FlowDocument

Because each Block is 'owned' by a FlowDocument, it cannot just be added to another. You must serialize it and then deserialize it, which breaks the bond with the original FlowDocument, which allows you to add it to another.

/// <summary>
/// Adds one flowdocument to another.
/// </summary>
/// <param name="from">From.</param>
/// <param name="to">To.</param>
public static void AddDocument(FlowDocument from, FlowDocument to)
{
    TextRange range = new TextRange(from.ContentStart, from.ContentEnd);
    MemoryStream stream = new MemoryStream();
    System.Windows.Markup.XamlWriter.Save(range, stream);
    range.Save(stream, DataFormats.XamlPackage);
    TextRange range2 = new TextRange(to.ContentEnd, to.ContentEnd);
    range2.Load(stream, DataFormats.XamlPackage);
}

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