Validation Groups allows the different section of the webpage to be validated seperately. All the ASP.NET 2.0 Validation controls,interactive form controls like TextBox,list controls Button and other controls that are used to submit a webform have validationGroup property. The default value of this property is the empty string. When a button with a ValidationGroup property is clicked all of the validation controls on the page with the same ValidationGroup property value are executed.
On postback, the Page.IsValid property checks the validity of all of the validation controls. Programmatically it can be checked by the Validate() Method.
Validation Groups
Name
Age
Enter Age between 18 To 58