Did you already know that the TextBox and RichTextBox controls in Windows Presentation Foundation offer spell check support? Yes, just like Microsoft Word, so typed words are checked and correct alternatives are proposed via a popup menu.
That's cool! But you can take the advantage of this only if your system is localized on English, French, Spanish and German languages.
Anyway, spell check can be enabled just setting the SpellCheck.IsEnabled attached property to True as follows:
<RichTextBox Name="Rtb1" SpellCheck.IsEnabled="True"/>
and this is just what we need to obtain the following result:
With just a half line of code we can implement an important feature in our word processing applications. There are a couple of limitations: the first one, is related to the available languages as mentioned above. The second one, custom dictionaries are not supported in this version of WPF.
If you're running the English localization of Windows Vista, remember to set the Language Bar to EN instead of the language set for your Country.