Each control has the following events and properties that are used to validate a form. Validation on a control is triggered when the control loses focus. Cancel Event Args] object as a parameter to the event block, which you can access this by using the in the Validating event, all events that would usually occur after the Validating event are suppressed.
Use this event to provide custom validation for any input control, such as a Text Box. In other words, the validating control will retain the focus until the user provides the correct format, even if the user clicks another control such as a button or textbox.
Value Range Text Box Represents a control that limits the input text to the format determined by the specified mask.
Mask will be composed from patterns and hardcoded chars.
Thankfully Win Forms has built in mechanisms to help facilitate data validation.
Having a generating function enables you to write much more dynamic Web applications.
Validation Text Box passes its constraints object to the generating function.
In addition to the “state” change, a pop-up appears.
When the pop-up appears screen readers should read the contents of the pop-up.