We will implement the business rule to allow test appointments to be setup on weekdays only using validation on the form. Add controls as shown in the figure below and set the properties of the controls as indicated in the table. The control is added to the form and displayed in the control tray in the Windows form in Design view. Now we will add the validations for the Date Time Picker controls which collects the Test Date information.The string specified in the second argument in the function invocation is displayed as the tooltip when the mouse is moved over the Error indicator.
More and more browsers now support the constraint validation API, and it's becoming reliable.This API consists of a set of methods and properties available on each form element.attribute to turn off the browser's automatic validation; this lets our script take control over validation.I recommend against relying on submission validation in a Windows Forms application.Errors should be trapped sooner, as close to when they are entered as possible.The regex pattern matches any integer value, with empty strings allowed. The rest of the method sets the error provider if the match failed, or clears it if the match succeeded.