using System;

using System.Collections.Generic;

using System.ComponentModel.DataAnnotations;

​

public class Cargo

{

        [Key]

        [Display(Name = "Código")]

        public int Codigo { get; set; }

​

        [Required(AllowEmptyStrings = false, ErrorMessage = "A descrição do cargo é obrigatória")]

        [Display(Name = "Descrição")]

        public string Descricao { get; set; }

​

        [Display(Name = "Ativo")]

        public bool Ativo { get; set; }

​

}

public class Program

{

    public static void Main()

    {

        Cargo cargo = new Cargo { };

        ModelValid modelValid = new ModelValid(cargo);

        if (modelValid.IsValid)

        {

            //objCargo.Inserir(cargo);

            Console.WriteLine("Model Válido");

        }

        else

        {

            Console.WriteLine(modelValid.ErrorMessages());

        }

    }

}

​

public sealed class ModelValid

{                                 

    public ICollection<ValidationResult> ValidationResults { get; private set; }

    public bool IsValid { get; private set; }

    public ModelValid(object model)            

    {

        ValidationResults = new List<ValidationResult>();

        IsValid = Validator.TryValidateObject(model, 

            new ValidationContext(model), 

            ValidationResults, true);            

    }

    public ModelValid(object model, bool throwIfExists)

        :this(model)

    {       

        if (throwIfExists) ThrowException();

    }

    public void ThrowException()

    {               

        throw new ValidationException(ErrorMessages());

    }  

    public string ErrorMessages()

    {

        string message = string.Empty;

        if (!IsValid)

        {

            if (ValidationResults != null &&

                ValidationResults.Count > 0)

            {                              

                IEnumerator<ValidationResult> results =

                    ValidationResults.GetEnumerator();

                while (results.MoveNext())

                {

                    ValidationResult vr = results.Current;

                    message += vr.ErrorMessage + System.Environment.NewLine;

                }                    

            }

        }

        return message;

    }

}