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Validation in ASP.NET MVC

Validation is an essential part of any web application development process. In ASP.NET MVC, validating user input is done with the help of validation attributes and validators. This page discusses how to perform validation in ASP.NET MVC.

Syntax

Validating data in ASP.NET MVC is done using validation attributes. There are several built-in validation attributes available in ASP.NET MVC, including Required, Range, RegularExpression, and others. Here is an example of using the Required attribute to validate a property:

[Required(ErrorMessage = "Your error message here")]
public string FirstName { get; set; }

This attribute ensures that the FirstName property contains a value and, if not, displays the specified error message.

Example

Here's an example of a simple ASP.NET MVC view model that uses validation attributes:

public class ContactFormViewModel
{
    [Required(ErrorMessage = "Please enter your name")]
    public string Name { get; set; }

    [Required(ErrorMessage = "Please enter your email address")]
    [EmailAddress(ErrorMessage = "Please enter a valid email address")]
    public string Email { get; set; }

    [Required(ErrorMessage = "Please enter a message")]
    [MinLength(10, ErrorMessage = "Your message must be at least 10 characters")]
    public string Message { get; set; }
}

The above example is a contact form view model that specifies validation attributes for each property.

Explanation

ASP.NET MVC provides various validation attributes and validators that can be used to validate user input. The Required attribute checks if a value is provided for a property, and if not, displays the specified error message. The Range attribute validates if a value is within a specific range, while the RegularExpression attribute validates if a value meets a specific pattern.

Besides the built-in validation attributes, it is also possible to create custom validation attributes for your specific needs.

Use

Validation is used to ensure that user input is correct, valid, and meets specific criteria. By applying validation attributes to properties in view models, you can ensure that user input is validated before it is saved to a database or used in other ways.

Important Points

  • Validation attributes are used for ensuring that user input meets specific criteria.
  • ASP.NET MVC provides various built-in validation attributes and validators.
  • Custom validation attributes can be created to meet specific needs.

Summary

Validation is a critical part of web application development, and ASP.NET MVC provides built-in validation attributes and validators to help validate user input. By applying validation attributes to view model properties, you can ensure that user input meets specific criteria and is validated before it is used.

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