How can I implement input validation in ASP.NET MVC?

How can I implement input validation in ASP.NET MVC?

You can implement input validation in ASP.NET MVC using data annotations. For example, you can use attributes like [Required], [StringLength], and [RegularExpression] on your model properties.

Can you give me an example of using the [Required] attribute?

Sure! In your model, you can define a property like this: public class User { [Required(ErrorMessage = "Name is required")] public string Name { get; set; } } This ensures that the Name field must be filled out.

What happens if the validation fails?

If validation fails, the model state will be invalid, and you can check this in your controller. You can return the user to the form with error messages displayed.

How can I display these error messages in the view?

You can use the Html.ValidationMessageFor helper in your view. For example: @Html.ValidationMessageFor(model => model.Name) will display the error message for the Name field.