Validation Groups

We have kept the examples shown in this chapter intentionally simple. In a real application, however, you might have a page with many controls on it. In addition, the page may be divided into sections, with more than one button that can submit the page, depending on what the user is doing.

At times, it is convenient to be able to say, “When I click the first button I want to validate only these first five controls, but when I click the second button I want to validate only the last four controls.” This allows you to create forms in which you expect that some of the controls will be invalid. For example, you might have a page in which you ask the user to enter her username and password (if registered) or to enter other information if creating a new account. Clearly, one or the other will be left blank.

To accomplish this, you set the ValidationGroup property on all the controls (and the button that submits the page) to the same value for each group. In the example just described, the first five controls and the first button might all have ValidationGroup set to GroupOne, yet all the other controls would have ValidationGroup set to GroupTwo. By default, all controls have their ValidationGroup property set to the empty string so they all validate at the same time until the property is set to something else.

To demonstrate, add a copy of CompareValidator.aspx to the website; call it ValidationGroup.aspx, and make two changes. First, move the two rows for password entry ...

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