Design for many different updates to an object?

I am stuck in a design issue. My problem is that my solution to the problem is not clean. And code looks not nice.

This is what I want to do:

I have an plain class with properies storing values. The class values must validate to certain rules.

This is a simplified example: A value class:

 class RecivedOrder
 {
     public AgreementId { get; set; }
     public OrderNr { get; set; }
     public Items { get; set; }
     public ProductId { get; set; }
     public ValidProductId { get; set; }         
     public InStock { get; set; }        
     public CustomerId { get; set; }     
     public NameOfCustomer { get; set; }         
     //..and many more properties..
 }

Validations/Update is done one the class like this:

 foreach (RecivedOrder o in RecivedDocument.Orders)
 {
    RecivedOrder.AgreementId = CheckIfValidAgreementId(o.AgreementId );
    RecivedOrder.ValidProductId = (bool)CheckIfValidProductId(o.ProductId);
    RecivedOrder.InStock = (bool)CheckProductIsInStock(o.ProductId);
    RecivedOrder.NameOfCustomer = GetNameOfCustomer(o.CustomerId);
    // ...and many more checks/validations....

    // The check methodes can do call to database..

 }

What I am looking for is a good design pattern for this. Or a cleaner way to do this?

Best Regards Fredrik