This tutorial shows how you can validate the input of users using ASP.NET and VB

This tutorial shows how the ASP.NET tools make it easy for you to validate user input, both client-side and server-side.

First we add the form elements from the Toolbox, including the RequiredFieldValidator, RegularExpressionValidator and the ValidationSummary. ***Note the CustomValidator control, which allows us to create a custom rule for validation.

This particular one checks to see if a date is in the correct format:

In the code-behind file we have the following:

For client-side validation of the date field, we can use a bit of JavaScript:

Note: For this to work, the ‘EnableClientScript’ Property of the CustomValidator has to be set to True.

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