I am afraid it will not be possible without writing your own logic to parse the incoming stream and convert it to a format suitable to be displayed in the RichTextBox.
Our Drag and Drop provider has just the capability to manage events around what you drag , where you drop it e.t.c. and not the content itself.
I would recommend for questions specific to "how to display your data in RadRichTextBox" to open a separate thread in the RadRichTextBox dedicated section.
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