Hi,
To load and save RTF files to and from C1RichTextBox, you can use the RtfFilter class from C1.WPF.RichTextBox.RtfFilter.dll. Please take a look at the RichTextBoxSamples > DemoRichTextBoxFilter.xaml at the following location on your machine : \Documents\ComponentOne Samples\Studio for WPF\C1.WPF.RichTextBox\CS\RichTextBoxSamples
Regards
Abdias