// If Equals() returns true for a pair of objects
// then GetHashCode() must return the same value for these objects.
public override int GetHashCode()
{
//Get hash code for the Name field if it is not null.
int hashIzolName = Type == null ? 0 : Type.GetHashCode();
//Get hash code for the Code field.
int hashTube = Tube.GetHashCode();
int hashLayer1 = Layer1.GetHashCode();
int hashLayer2 = Layer2.GetHashCode();
int hashLayer3 = Layer3.GetHashCode();
//Calculate the hash code for the product.
//return hashProductName ^ hashProductCode;
return(hashIzolName ^ hashTube ^ hashLayer1 ^ hashLayer2 ^ hashLayer3);
}