Validating multiple controls
Dim fonts As New Observable Collection(of Font Family) Public Sub New() My Base. List Box controls are always open, so several items can be displayed without user interaction.
Use a List Box when you want the options to be visible all the time or when users can select more than one option at a time.
Page_Is Valid Boolean variable Indicates whether the page is currently valid.
The validation scripts keep this up to date at all times.
Set this variable to False to turn off validation programmatically.isvalid Boolean property This is a property on each client validator indicating whether it is currently valid.
Page_Validation Summaries Array of elements This is an array containing all of the validation summaries on the page.
You can get or set the selected items for the list box by using the Selected Items property.
You populate the List Box control by adding UIElement items directly to the Items collection, or by binding the Items Source property to a data source.
You just define a set of validation rules that need to be checked for each of the targets and later, when appropriate, it is easy to just validate a target and get the validation result back without worrying what rules need to be checked.Implement IData Error Info and INotify Data Error Info interfaces The library includes Data Error Info Adapter and Notify Data Error Adapter classes that make the implementation of IData Error Info and INotify Data Error Info interfaces in your view models trivial. Validation is important part of any web application.Creating an instance of the helper In order to use the library you need to create an instance of the Validation Helper helper class and store it in an instance field of the class where you want to implement validation.If you do a lot of validation, it is probably the best to do it in your View Model Base class.