Recommendation for WinForms Spell Checker

I have a WinForms application for editing text i开发者_如何学运维n a large RichTextBox control.

Can anyone suggest the easiest (and hopefully cheapest) way to add spell checking to the RichTextBox control?

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One option is to use hosted content and place a WPF control that offers spell checking. For example the WPF RichTextBox has a property SpellCheck which you can enable.

Note that WPF uses its own spellchecker and doesn't require Microsoft Office.