It is possible to provide the user with immediate feedback on bad input and to prevent them from posting a page until it has been corrected.However, it can be almost impossible to guarantee that every user of your site has the required scripting environment.Large data entry pages generally have an area where all errors are listed.The Validation Summary automatically generates this content by gathering it up from validator controls on the page. It exposes the all-important "Is Valid" property, which you check in server code to determine if all of the user input is OK.Remember, this is is just a start to solve the problem.
Let's refine our previous definition a little: "A validator is a control that checks one input control for a specific type of error condition and displays a description of that problem." This is an important definition, because it means that you frequently need to use more than one validator control for each input control. When you initialize a managed document, you specify the URL for the document location.The document object then creates a Core Data stack to use to access the document’s persistent store using a managed object model from the app’s main bundle.Validator Walk-Through It's Not Voluntary Getting Regular Comparing Apples and Apples Custom Fit The Finale Sample Code Validating user input is a common scenario in a Web-based application.For production applications, developers often end up spending a lot more time and code on this task than we would like. NET page framework, it was important to try and make the task of validating input a lot easer than it has been in the past.For example, if you want to check whether or not user input in a text box is (a) nonblank, (b) a valid date between a particular range and (c) less than the date in another text input control, you would want to use three validators.While this might seem cumbersome, remember that to be helpful to the user, you would want to have three different text descriptions for all these cases.It generally appears to the user as a piece of text that displays or hides depending on whether the control it is checking is in error.It can also be an image, or can even be invisible and still do useful work.Validation controls change all that, because almost all the duplicated logic is encapsulated in the controls.If a client with Internet Explorer 4.0 or later uses your page, it can do the same input validation that takes place on the server without you having to write any special client script.