DatePicker control Silverlight 3 Behaviour

I have datepicker control in my form, when user enter some invalid text, or some other character using keyboard, then the text property doesn't show the user开发者_如何学C entered text which is invalid, But the arguments in the DateValidationError function does containt the invalid user input in the e.Text property, how do I get that invalid user input from the datepicker control text property ?

Thanks in advance .