How does model binding work in ASP.NET with validation attributes?

How does model binding work in ASP.NET with validation attributes?

In ASP.NET, model binding is the process of converting data from HTTP requests into .NET objects. Validation attributes are used to enforce rules on these models, ensuring that the data meets specific criteria before being processed.

Can you give me an example of a validation attribute?

Sure! One common validation attribute is the [Required] attribute. It ensures that a property must have a value. For example, if you have a model with a property like public string Name { get; set; }, you can decorate it with [Required] to enforce that the Name must not be null or empty.

What happens if the validation fails?

If validation fails, the model state becomes invalid, and you can check this in your controller. You can return validation errors to the user, typically by using ModelState.IsValid to determine if the model passed all validation checks.

How can I customize validation messages?

You can customize validation messages by specifying a message in the attribute. For example, [Required(ErrorMessage = "Name is required.")] allows you to set a custom error message that will be displayed if validation fails.