Windows form control validating validated
Most developers craft hard-coded program logic to verify that a phone number consists of 7 or 10 digits; that an IP address consists of 4 octets; that a country name matches 1 of 193 choices, etc. NET 2.0 provides some support for streamlining input validation, it barely scratches the surface of automating and simplifying the input validation process.If you ever search MSDN for the topic, you'll find most of the articles discuss hard-coded validationbut maintaining hand-written, custom code for each element that requires validation is a maintenance nightmare.
That was what microsoft support provided, so I published it in case it helps someone. I agree I would rather have the bugs with 2005 fixed 100% rather than a new version.So the event occurs when you use the tab key to move away from the current control or when you click another control with the mouse.Note that the method in the example takes a Control as its first argument.I much prefer the helps explanation as it makes binding useable in the real world. nput validation is something that every program needs, and every programmer dreads.A modular, data-driven validation engine approach provides a more natural interface, more flexibility, and is easier to maintain.
Visual Studio lets you specify property values at design time for a variety of components; using that approach for defining validation attributes is a natural extension, and makes incorporating robust validation simpler for developers.
Also following the 80/20 rule, to cover the remaining use cases would require 80 percent of the effort (i.e.
the effort expended to get this far would be multiplied five-fold).
One thing I've tried, to work around this, is to call Cancel Edit() on the binding source within the Validating event along with e.
Cancel = true; This prevents the property set on the object to be called. I have been advised by microsoft support that the documentation will be updated to reflect the actual behaviour and to raise this using the feedback system for .
Dragging an Error Provider onto the visual designer (or instantiating it in code) gives you the basic component required to display validation messages.