using System;

using FluentValidation;

using System.Data.SqlTypes;

​

​

public class Entity

{

    public DateTime EffectiveDate {get; set;}

​

    public bool IsRewrite {get; set;}   

}

​

public class EntityValidator : AbstractValidator<Entity>

{

    public EntityValidator()

    {

        RuleFor(pt => pt.EffectiveDate)

                .GreaterThan(date => SqlDateTime.MinValue.Value).WithMessage("PolicyTransaction EffectiveDate {0} is invalid", pt => pt.EffectiveDate)

                .Must(ed => ed.Date == DateTime.Today ).When(pt => pt.IsRewrite).WithMessage("PolicyTransaction EffectiveDate {0} must be set to today's date.", pt => pt.EffectiveDate);

    }       

}

​

public class Program

{

    public static void Main()

    {

        var entityValidator = new EntityValidator(); 

        Entity toValidate = new Entity();

        toValidate.EffectiveDate = DateTime.MinValue;

        toValidate.IsRewrite = true;

        try

        {

            entityValidator.ValidateAndThrow(toValidate);

            Console.WriteLine("Everything is fine.");

        }

        catch(Exception ex)

        {

            Console.WriteLine(ex.Message);

        }

    }

}