For example, if a button control with a validation group of property reflects the validity of all groups validated so far.This could include both a group that was validated as a result of a postback, and the programmatically validated group.When the user submits a page to the server, the validation controls are invoked to check the user input, control by control.
For example, you might want to specify both that a user entry is required and that the user entry is limited to accepting dates within a specific range.
You can attach more than one validation control to an input control on a page.
This can improve response time in the page because errors are detected immediately and error messages are displayed as soon as the user leaves the control containing the error. NET performs validation on the server even if the validation controls have already performed it on the client, so that you can test for validity within your server-based event handlers.
If client-side validation is available, you have greater control over the layout of error messages and can display an error summary in a message box. In addition, re-testing on the server helps prevent users from being able to bypass validation by disabling or changing the client script check.
Validation groups allow you to organize validation controls on a page as a set.
Each validation group can perform validation independently from other validation groups on the page.You can invoke validation in your own code by calling a validation control's Each validation control typically performs one test.However, you might want to check for multiple conditions.If you detect an invalid state, you bypass the update.Typically, if any validation checks fail, you skip all of your own processing and return the page to the user.When user input is being processed (for example, when a page is submitted), the validation control tests the user input and sets a property to indicate whether the input passed the test.