You are correct - the dialog's file filter could be passed as a CommandParameter to the SaveCommand command. For example, if you want to export only Pdf or Rtf files, you can use the following markup in the declaration of the RadRichTextBoxRibbonUI:
"PDF Files (*.pdf)|*.pdf|Rich Text Format (*.rtf)|*.rtf"
In order you want to export only Pdf files, you can set the CommandParameter property to 'pdf
' string only.
I hope this helps.
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