Validating user input in vb net
Simply put, never trust the data in an incoming request, and always validate on the server.
When validation fails the normal flow of execution continues.
If the conversion fails, the validation also fails.
To demonstrate the Range Validator, we will add an additional Text Box control to our web form (Hire Date Text Box), and a Range Validator.
The one exclusion to this rule is the Custom Validator component.
For this first example we do not need to place much code into the code-behind file. NET runtime does not waste time processing a request with invalid information.
Html Controls; namespace Web Data Validation When the user clicks the Cancel button we clear the Text Box control and allow the user to start over.
There are good reasons to always execute validation checks on the server.
Before accepting data from over the network you need to ensure all of the required fields have been filled out and conform to your formats and business rules. NET provides a number of validation controls to ease the burden of performing validation on both sides of the network. To walk along with the example, create a new web application in Visual Studio . Once the application is setup, right click on the empty web form, select Properties from the context menu, and change the Page Layout property to Flow Layout. Notice we need to check the Is Valid property of the base class before performing any critical action in the submit event.
Place four controls from the Web forms section of the Toolbox onto the form. If Is Valid returns a value of true then all of the validation checks were successful.
There are four key properties to initialize for a Range Validator.