How can I handle validation error messages in ASP.NET?

How can I handle validation error messages in ASP.NET?

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

Yes, please provide an example of using data annotations.

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

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

How do I display these error messages in the view?

You can display error messages in your Razor view using the Html.ValidationMessageFor helper. For example:

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

What if I want to customize the error messages further?

You can customize error messages by providing a custom message in the data annotation attributes or by using a validation summary to display all errors at once.