Validating asp net
User's input must always be validated before sending across different layers of the application.
Validation controls are used to: Client side validation is good but we have to be dependent on browser and scripting language support. NET Web pages for user input is to be able to check that the information users enter is valid. NET provides a set of validation controls that provide an easy-to-use but powerful way to check for errors and, if necessary, display messages to the user. NETUsually, Validation is invoked in response to user actions like clicking submit button or entering data.
Importantance of returning false It's very important to use the return false statement after the condition block that return false so if validation determines that the business requirements are not met then the form cannot be submitted.
Validation is important part of any web application.
The following table summarizes the commonly used syntax constructs for regular expressions: The Custom Validator control allows writing application specific custom validation routines for both the client side and the server side validation.
The client side validation is accomplished through the Client Validation Function property.
This article discusses how to validate information you get from users — that is, to make sure that users enter valid information in HTML forms in an ASP. What you'll learn: If you ask users to enter information in a page — for example, into a form — it's important to make sure that the values that they enter are valid.Server Side Validation Validation done at the server level after sending the form data to the server but before entering the data into the database is called server-side validation. The first page source code Look at the preceding source code closely; see the id's of controls that play the important role in Java Script validation by reading the ASP. The design view of the preceding source code will look as in the following: I hope you have created the same form as above for demonstration purposes. Net controls values in Java Script are as: There are three main methods shown in the above image in the red square to read the ASP.Net controls values; they are:get Element By Id: this method is used to read the controls values by their Element By Name: this method is used to read the controls values by their Element By Tag Name: this method is used to read the controls values by their Tag Name.Therefore, it would help to take a look at the properties and the methods of this base class, which are common for all the validation controls: The Regular Expression Validator allows validating the input text by matching against a pattern of a regular expression.The regular expression is set in the Validation Expression property.