How do you constrain the Silverlight Datepicker without a MaxLength property?

I have a Silverlight Datepicker control. I would like to constrain entry to only allow 10 characters. Currently it see开发者_Go百科ms to be unlimited.

There is no maxlength property on the control. Can it be set in another way?

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Just a shot in the dark but did you have a look at the DatePicker's style? I remember having some issues with it and making the text box readonly.