Windows Phone 7 Spell Check on textboxes

How do I implement the spell check feature for 开发者_运维知识库my large text boxes for my app?

Generally there is no spell check. If you are talking about generalized suggestions, you can get those by using a specific SIP (Software Input Panel) - Text.

Official documentation: MSDN

You will have to manually specify the InputScope:

<TextBox>
    <TextBox.InputScope>
        <InputScope>
            <InputScopeName NameValue="Text"/>
        </InputScope>
    </TextBox.InputScope>
</TextBox>