What are the validation controls and how many validation controls are there in ASP.NET 4.0?

Answer 1

Validation controls allows you to validate a control against a set of rules. There are 6 different validation controls used in ASP.NET 2.0. RequiredFieldValidator - Checks if the control is not empty when the form is submitted. CompareValidator - Compares the value of one control to another using a comparison operator (equal, less than, greater than etc). RangeValidator - Checks whether a value falls within a given range of number, date or string. RegularExpressionValidator - Confirms that the value of a control matches a pattern defined by a regular expression. Eg: email validation. CustomValidator - Calls your own custom validation logic to perform validations that cannot be handled by the built in validators. ValidationSummary - Show a summary of errors raised by each control on the page on a specific spot or in a message box.

Answer 2

Validation controls are responsible to validate the data of an input control. Whenever you provide any input to an application, it performs the validation and displays an error message to user, in case the validation fails.

ASP.NET 4.0 contains the following six types of validation controls:

• CompareValidator - Performs a comparison between the values contained in two controls.
• CustomValidator - Writes your own method to perform extra validation.
• RangeValidator- Checks value according to the range of value.
• RegularExpressionValidator - Ensures that input is according to the specified pattern or not.
• RequiredFieldValidator - Checks either a control is empty or not.
• ValidationSummary - Displays a summary of all validation error in a central location.