RadRichTextBox provides you with the ability to export its contents to a number of formats - XAML, DOCX, RTF, HTML and plain text. The exported document can then be imported back in the control without issues. Depending on your scenario, you could adopt any of the formats by adding the needed assembly reference/s in your project. Please refer to the list of needed assemblies and the Import/Export section of the documentation for further information and some examples.
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