来自数据库的MVC 5验证数据注释

Question

I have been looking for ways to make a custom validation (its haaaaaard) using data from a DB. For example, i have in my project a EntityFramework enviromment. So, how I can do to make a custom validation using data annotations and compare some value with a DB item?

For example:

I want o validate a field call "Code" to see if exists in the DB. If not, i want a message "Error: you must use a valid code"

Can you help me?

Thanks!

Answer 1

Done!

With the help of Stephen Muecke and this pages:

• http://msdn.microsoft.com/en-us/library/gg508808(vs.98).aspx
• http://sebys.com.ar/2014/03/24/asp-net-mvc-4-remote-validation/

But the credits is for Stephen and the Remote Validation. Thanks!!

Controller:

public JsonResult ExisteCodOp(string Codigo_Operador)
    {
        ModeloDePool1 ModeloPool1 = new ModeloDePool1();

        bool ExisteCodOp = ModeloPool1.CheckCodOp(Codigo_Operador);

        if (ExisteCodOp == false)
        {
            return Json("No existe el KVD escrito.", JsonRequestBehavior.AllowGet);
        }
        else
        {
            return Json(true, JsonRequestBehavior.AllowGet);
        }

Model:

        [Required]
    [RegularExpression(@"[Tt,Ss]-\d\d", ErrorMessage="Debe colocar un Código de Operador válido.")]
    [Remote("ExisteCodOp","Pool")]
    [DisplayName("Código Operador")]
    public string Codigo_Operador { get; set; }