How many validations in asp.net

Code First ensures that the validation rules you specify on a model class are enforced before the application saves changes in the database. For example, the code below will throw a DbEntityValidationException exception when the SaveChanges method is called, because several required Movie property values are missing:.

Validation failed for one or more entities. See 'EntityValidationErrors' property for more details. Having validation rules automatically enforced by the. NET Framework helps make your application more robust.

It also ensures that you can't forget to validate something and inadvertently let bad data into the database. Click the Create New link to add a new movie.

Fill out the form with some invalid values. As soon as jQuery client side validation detects the error, it displays an error message. Notice how the form has automatically used a red border color to highlight the text boxes that contain invalid data and has emitted an appropriate validation error message next to each one. The errors are enforced both client-side using JavaScript and jQuery and server-side in case a user has JavaScript disabled.

A real benefit is that you didn't need to change a single line of code in the MoviesController class or in the Create. The controller and views you created earlier in this tutorial automatically picked up the validation rules that you specified by using validation attributes on the properties of the Movie model class.

Test validation using the Edit action method, and the same validation is applied. The form data is not sent to the server until there are no client side validation errors. You might wonder how the validation UI was generated without any updates to the code in the controller or views. The next listing shows what the Create methods in the MovieController class look like.

They're unchanged from how you created them earlier in this tutorial. The second [HttpPost] version handles the form post. IsValid to see whether the movie has any validation errors. Getting this property evaluates any validation attributes that have been applied to the object.

If the object has validation errors, the Create method redisplays the form. If there are no errors, the method saves the new movie in the database. In our movie example, the form isn't posted to the server when there are validation errors detected on the client side; the second Create method is never called. IsValid to check whether the movie has any validation errors.

You can set a break point in the HttpPost Create method and verify the method is never called, client side validation will not submit the form data when validation errors are detected.

If you disable JavaScript in your browser, then submit the form with errors, the break point will be hit. You still get full validation without JavaScript. The following image shows how to disable JavaScript in Internet Explorer.

Below is the Create. It's used by the action methods shown above both to display the initial form and to redisplay it in the event of an error. Notice how the code uses an Html.

Next to this helper is a call to the Html. ValidationMessageFor helper method. These two helper methods work with the model object that's passed by the controller to the view in this case, a Movie object. They automatically look for validation attributes specified on the model and display error messages as appropriate. What's really nice about this approach is that neither the controller nor the Create view template knows anything about the actual validation rules being enforced or about the specific error messages displayed.

The validation rules and the error strings are specified only in the Movie class. The RequiredFieldValidator control ensures that the required field is not empty. It is generally tied to a text box to force input into the text box. The CompareValidator control compares a value in one control with a fixed value or a value in another control. The RegularExpressionValidator allows validating the input text by matching against a pattern of a regular expression.

The regular expression is set in the ValidationExpression property. Apart from single character match, a class of characters could be specified that can be matched, called the metacharacters. The CustomValidator 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 ClientValidationFunction property.

The client side validation routine should be written in a scripting language, such as JavaScript or VBScript, which the browser can understand. The server side validation routine must be called from the control's ServerValidate event handler.

Data format, data type and data range is used for validation. Validation is of two types Client Side Serve Side Client side validation is good but we have to be dependent on browser and scripting language support.

Client side validation is considered convenient for users as they get instant feedback. The main advantage is that it prevents a page from being postback to the server until the client validation is executed successfully.

For developer point of view serve side is preferable because it will not fail, it is not dependent on browser and scripting language. You can use ASP. NET validation, which will ensure client, and server validation. It work on both end; first it will work on client validation and than on server validation.

At any cost server validation will work always whether client validation is executed or not. So you have a safety of validation check. For client script. NET used JavaScript. 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.

There are six types of validation controls in ASP. One validation control will validate only one input control but multiple validate control can be assigned to a input control. Validation Properties Usually, Validation is invoked in response to user actions like clicking submit button or entering data.

Suppose, you wish to perform validation on page when user clicks submit button. Server validation will only performed when CauseValidation is set to true. When the value of the CausesValidation property is set to true, you can also use the ValidationGroup property to specify the name of the validation group for which the Button control causes validation.

Page has a Validate method. If it is true this methods is executed. Validate executes each validation control. You can have a RequiredFieldValidator control for each form element on which you wish to enforce Mandatory Field rule. It can most commonly be used when you need to confirm password entered by the user at the registration time. The data is always case sensitive. Using RegularExpressionValidator server control, you can check a user's input based on a pattern that you define using a regular expression.

It is used to validate complex expressions. These expressions can be phone number, email address, zip code and many more. Using Regular Expression Validator is very simple. Simply set the ValidationExpression property to any type of expression you want and it will validate it.