With ASP.NET 2.0, this problem is addressed through the introduction of Validation Groups. All validation controls and all controls that cause a postback support this new property. The ValidationGroup property is just a simple text field. When a postback occurs, only those validators whose ValidationGroup matches the postback control's ValidationGroup (even if it is blank, the default) are fired. This simple yet elegant solution solves a significant problem with the 1.x implementation of validation.
Validation groups are also supported in code. A particular group's validity can be checked using
If (Page.Validate("GroupName")) Then
Also, the standard Page.IsValid now evaluates the ValidationGroup associated with the last PostBack.