mvc4 data annotation compare two dates

Question

I have these two fields in my model:

[Required(ErrorMessage=\"The start date is required\")]
[Display(Name=\"Start Date\")]
[DisplayFormat(DataFormatString =         


        

Answer 1

IValidatableObject interface provides a way for an object to be validated which implements IValidatableObject.Validate(ValidationContext validationContext) method. This method always return IEnumerable object. That's why you should create list of ValidationResult objects and errors are added to this and return. Empty list means to validate your conditions. That is as follows in mvc 4...

 public class LibProject : IValidatableObject
{
    [Required(ErrorMessage="Project name required")]

    public string Project_name { get; set; }
    [Required(ErrorMessage = "Job no required")]
    public string Job_no { get; set; }
    public string Client { get; set; }
    [DataType(DataType.Date,ErrorMessage="Invalid Date")]
    public DateTime ExpireDate { get; set; }


    IEnumerable IValidatableObject.Validate(ValidationContext validationContext)
    {
        List < ValidationResult >  res =new List();
        if (ExpireDate < DateTime.Today)
        {
            ValidationResult mss=new ValidationResult("Expire date must be greater than or equal to Today");
            res.Add(mss);

        }
        return res; 
    }
}