[SOLVED] What is the proper way of passing information between checkout steps? (NOP 1.90)

Hello again.

I'm trying to add a new checkout step to NOP, so that when customer selects Parcel Machine as delivery option, new step appear. I was able to add new step, and now I can select the options I want in there... but they are not saved after I click the Next button. I modified Customer class by adding two custom attributes like this:

#region Custom Properties

public string LastPrimaryParcelMachine { get; set; }
public string LastSecondaryParcelMachine { get; set; }

but when I use the following code:

protected void btnNextStep_Click(object sender, EventArgs e)
{
  if (Page.IsValid)
  {
    NopContext.Current.User.LastPrimaryParcelMachine = ddlPreferedParcelMachine.SelectedValue;
    NopContext.Current.User.LastSecondaryParcelMachine = ddlAlternateParcelMachine.SelectedValue;
    this.CustomerService.UpdateCustomer(NopContext.Current.User);

    var args1 = new CheckoutStepEventArgs() { PrimaryAndSecondaryPaczkomatSet = true };
    OnCheckoutStepChanged(args1);
    if (!this.OnePageCheckout)
      Response.Redirect("~/checkoutpaymentmethod.aspx");
  }
}

the NopContext.Current.User.LastPrimaryParcelMachine and NopContext.Current.User.LastSecondaryParcelMachine properties are null inside the next step, while others (ShippingAddressId for example) are not null.

What am I doing wrong?

Thanks in advance

OK, I figured it out - simple {get;set;} won't do, something like this:

public string LastPreferedParcelMachine
        {
            get
            {
                string lastPreferedParcelMachine = null;
                CustomerAttribute lastPreferedParcelMachineAttr = this.CustomerAttributes.FindAttribute("LastPreferedParcelMachine", this.CustomerId);
                if (lastPreferedParcelMachineAttr != null)
                {
                    lastPreferedParcelMachine = lastPreferedParcelMachineAttr.Value;
                }

                return lastPreferedParcelMachine;
            }
            set
            {
                CustomerAttribute lastPreferedParcelMachineAttr = this.CustomerAttributes.FindAttribute("LastPreferedParcelMachine", this.CustomerId);
                if (value != null)
                {
                    if (lastPreferedParcelMachineAttr != null)
                    {
                        lastPreferedParcelMachineAttr.Value = value;
                        IoC.Resolve<ICustomerService>().UpdateCustomerAttribute(lastPreferedParcelMachineAttr);
                    }
                    else
                    {
                        lastPreferedParcelMachineAttr = new CustomerAttribute()
                        {
                            CustomerId = this.CustomerId,
                            Key = "LastPreferedParcelMachine",
                            Value = value
                        };
                        IoC.Resolve<ICustomerService>().InsertCustomerAttribute(lastPreferedParcelMachineAttr);
                    }
                }
            }
        }
        public string LastAlternateParcelMachine 
        {
            get
            {
                string lastAlternateParcelMachine = null;
                CustomerAttribute lastAlternateParcelMachineAttr = this.CustomerAttributes.FindAttribute("LastAlternateParcelMachine", this.CustomerId);
                if (lastAlternateParcelMachineAttr != null)
                {
                    lastAlternateParcelMachine = lastAlternateParcelMachineAttr.Value;
                }

                return lastAlternateParcelMachine;
            }
            set
            {
                CustomerAttribute lastAlternateParcelMachineAttr = this.CustomerAttributes.FindAttribute("LastAlternateParcelMachine", this.CustomerId);
                if (value != null)
                {
                    if (lastAlternateParcelMachineAttr != null)
                    {
                        lastAlternateParcelMachineAttr.Value = value;
                        IoC.Resolve<ICustomerService>().UpdateCustomerAttribute(lastAlternateParcelMachineAttr);
                    }
                    else
                    {
                        lastAlternateParcelMachineAttr = new CustomerAttribute()
                        {
                            CustomerId = this.CustomerId,
                            Key = "LastAlternateParcelMachine",
                            Value = value
                        };
                        IoC.Resolve<ICustomerService>().InsertCustomerAttribute(lastAlternateParcelMachineAttr);
                    }
                }
            }
        }