How to convert convert string to RTF format in RichTextBox inside a DataTemplate of a DataGrid?

Question

I have a string in the format of RTF coming from a database. The string is the following:

{\rtf1\ansi\ansicpg1252\uc1\htmautsp\deff2{\fonttbl{\f0\fcharset0 Times New Roman;}{\f2\fcharset0 Segoe UI, Lucida Sans Unicode, Verdana;}}{\colortbl\red0\green0\blue0;\red255\green255\blue255;}\loch\hich\dbch\pard\plain\ltrpar\itap0{\lang1033\fs18\f2\cf0 \cf0\ql{\f2 {\ltrch This is a sentence}\li0\ri0\sa0\sb0\fi0\ql\par}
}
}

I have the following as the DataGrid XAML code:

<DataGrid Name="dg">
    <DataGrid.Columns>
        <DataGridTextColumn Header="Col1" Binding="{Binding Col1}"/>
        <DataGridTextColumn Header="Col1" Binding="{Binding Col1}"/>
    </DataGrid.Columns>
    <DataGrid.RowDetailsTemplate>
        <DataTemplate>
            <RichTextBox>
                <FlowDocument>
                    <Paragraph>
                        <Run Text="{Binding Text}" />
                    </Paragraph>
                </FlowDocument>
            </RichTextBox>
        </DataTemplate>
    </DataGrid.RowDetailsTemplate>
</DataGrid>

The problem I am having is that the value coming from the database is being displayed but it is in the RTF format.

I am not sure as to how to convert this so that the RichTextBox will display the appropriate formatting for the text.

I have the following method which loads up the data into the RichTextBox but the problem is I need to know the name of the RichTextBox first.

public static string convertString_RTF(string text, RichTextBox rtb)
{
    string rtfText = text;
    byte[] byteArray = Encoding.ASCII.GetBytes(rtfText);
    using (System.IO.MemoryStream ms = new System.IO.MemoryStream(byteArray))
    {
        System.Windows.Documents.TextRange tr = new System.Windows.Documents.TextRange(rtb.Document.ContentStart, rtb.Document.ContentEnd);
        tr.Load(ms, System.Windows.DataFormats.Rtf);
    }
    return null;
}

What would be a solution to displaying the RTF string in the RichTextBox through binding?

Thank you in advance for your help.

Answer 1

1. Create your own RichTextBox, and introduce a new DependencyProperty called TextProperty.

   public class MyRichTextBox : RichTextBox
   {
       public string Text
       {
         get { return (string)GetValue(TextProperty); }
         set { SetValue(TextProperty, value); }
       }
   
       // Using a DependencyProperty as the backing store for Text.  This enables animation, styling, binding, etc...
       public static readonly DependencyProperty TextProperty =
              DependencyProperty.Register("Text", typeof(string), typeof(MyRichTextBox), new PropertyMetadata(String.Empty, new PropertyChangedCallback(TextChanged_Handler)));
   
       private static void TextChanged_Handler(DependencyObject d, DependencyPropertyChangedEventArgs e)
       {
           RichTextBox rtb = d as RichTextBox;
   
           byte[] array = Encoding.ASCII.GetBytes(e.NewValue.ToString());
           using (MemoryStream stream = new MemoryStream(array))
           {
               TextRange t = new TextRange(rtb.Document.ContentStart,
                               rtb.Document.ContentEnd);
               t.Load(stream, System.Windows.DataFormats.Rtf);
           }                
        }       
   }
   

Usage :

<local:MyRichTextBox Margin="20" Text="{Binding RtfCol}" Width="300" Height="300" />

2. You can also take the route of AttachedProperty.

Answer 2

Because you need use RichTextBox.Load, you can't bind directly. Use a converter like this:

    [ValueConversion(typeof(string), typeof(string))]
    public class RTFConverter : IValueConverter
    {
        RichTextBox rtBox = new RichTextBox();
        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
        {
            string rtf = (string)value;
            convertString_RTF(rtf, rtBox);
            TextRange textRange = new TextRange(rtBox.Document.ContentStart, rtBox.Document.ContentEnd);
            return textRange.Text;
        }
        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
        {
            return null;
        }
    }

<Window.Resources>
   <local:RTFConverter x:Key="RTFConverter"/>
</Window.Resources>
<RichTextBox x:Name="richtxt" VerticalAlignment="Bottom" >
    <FlowDocument>
        <Paragraph>
            <Run Text="{Binding Text, Converter={StaticResource RTFConverter}}" />
        </Paragraph>
    </FlowDocument>
</RichTextBox>