I have written a usercontrol based on a textbox that will format and validate the data entered to the required set property, ie. Y2K date, long, decimal to two places, etc. It works well but has a serious flaw. The control uses the show,lostfocus and resize events to format and validate its data. However if I want to place a calculated value into the control from an action somewhere else none of the above events get called and I have raw data in the control. Is there a way to kick the usercontrol into realising that its data has been changed?.