How can I handle validation errors in ASP.NET?

How can I handle validation errors in ASP.NET?

In ASP.NET, you can handle validation errors using data annotations and model state validation. Would you like to see an example?

Yes, please provide an example of using data annotations.

Sure! You can use attributes like [Required] and [StringLength] in your model class. For instance:

public class UserModel {
    [Required(ErrorMessage = "Name is required.")]
    public string Name { get; set; }

    [StringLength(100, ErrorMessage = "Email cannot be longer than 100 characters.")]
    public string Email { get; set; }
}

How do I display these validation messages in the view?

You can use the Html.ValidationMessageFor helper in your Razor view to display validation messages. For example:

@Html.ValidationMessageFor(model => model.Name)

What if I want to customize the error messages?

You can customize error messages by specifying the ErrorMessage property in the data annotation attributes, as shown in the previous example.