Convert Xaml file to FlowDocument with as operator

   
  


<Window x:Class="WpfApplication1.Window1"
  xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
  Title="FlowDocReader Load/Save Sample" Width="640" Height="480">
  <StackPanel>
    <FlowDocumentReader Name="FlowDocRdr" Grid.Row="1"/>
  </StackPanel>
</Window>

//File:Window.xaml.cs
using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Shapes;
using System.Windows.Forms;
using System.IO;
using System.Windows.Markup;

namespace WpfApplication1
{

    public partial class Window1 : Window
    {

        public Window1()
        {
            InitializeComponent();

            FlowDocument content = null;
            
            OpenFileDialog openFile = new OpenFileDialog();
            openFile.Filter = "FlowDocument Files (*.xaml)|*.xaml|All Files (*.*)|*.*";

            if (openFile.ShowDialog() == System.Windows.Forms.DialogResult.OK)
            {
                FileStream xamlFile = openFile.OpenFile() as FileStream;
                if (xamlFile == null) return;
                else
                {   
                    try 
                    { 
                        content = XamlReader.Load(xamlFile) as FlowDocument; 
                        if (content == null) 
                            throw(new XamlParseException("The specified file could not be loaded as a FlowDocument."));
                    }
                    catch (XamlParseException e)
                    {
                        String error = "There was a problem parsing the specified file:

";
                        error += openFile.FileName;
                        error += "

Exception details:

";
                        error += e.Message;
                        System.Windows.MessageBox.Show(error);
                        return;
                    }
                    catch (Exception e) 
                    {
                        String error = "There was a problem loading the specified file:

";
                        error += openFile.FileName;
                        error += "

Exception details:

";
                        error += e.Message;
                        System.Windows.MessageBox.Show(error);
                        return;
                    }

                    FlowDocRdr.Document = content;
                }
            }
        }
    }
}