Tweet Form validation is an important element in every web site.
In order to be sure that the user submits data in accordance to what our code (or backend database) is expecting, it is mandatory to check the information before doing anything else.
By default, MVC uses the type name to search for a matching Editor/Display Template.
For instance, we use the following template for a string: And it will render like this, complete with label, with a nice Bootstrap design: Because the Title field has an attribute “required”, there should be an error when we leave it empty.
Form validation is the process of checking that a form has been filled in correctly before it is processed.
For example, if your form has a box for the user to type their email address, you might want your form handler to check that they've filled in their address before you deal with the rest of the form.
There are two main methods for validating forms: (usually done using Java Script).
Server-side validation is more secure but often more tricky to code, whereas client-side (Java Script) validation is easier to do and quicker too (the browser doesn't have to connect to the server to validate the form, so the user finds out instantly if they've missed out that required field! In this tutorial we'll build a simple form with client-side Java Script validation.
In the Properties dialog box find the Control To Validate property and select First Name Text Box from the drop down list. We can set other properties, such as the Error Message property, and the final ASPX source code should look like the following. NET work in a similar fashion to what we've seen above. If the client's web browser is of executing client side Java Script, the first validation pass occurs on the client.
Never forget to validate the submitted data to server.
Also remember to perform server-side validation in addition to client side validation as Java Script can be turned off by the user, there by bypassing the validation on client-side!
Drag one Text Box control and give it an ID of First Name Text Box, two Button controls (Submit Button and Cancel Button), and one Required Field Validator (First Name Required Field Validator). The following screen shows the form in action, and the user has pressed the Submit button without entering any text into the textbox. The Required Field Validator fails when the value in the associated control matches the value of the Initial Value property of the Required Field Validator.
This Required Field Validator forces the user to enter text into the control associated with the validator. If you want to make sure the user changes a default value placed into the control, set the control’s Text value and the Initial Value property of the Required Field Validator to the same value.
Shows you how to write a script that ensures your form is filled in correctly before it's sent to your server.