要得到DatePicker的textchange属性， 必须通过TextBoxBase.TextChanged 事件来处理。  想要判断是否当前DatePicker的textbox获取到焦点， 可以通过以下代码：  privatevoiddtpBirth_TextChanged(objectsender,TextChangedEventArgse)        {           //           IInputElementchild=FocusManager.GetFocusedElement(window);           DatePickerdtp=senderasDatePicker;           if(null!=child)            {               IInputElementelement=dtp.InputHitTest(Mouse.GetPosition(dtp));               if(null!=element)                {                   dtpBirth.Tag=true;                }                           }        }