Redirect to another VF page while using a Same Controller?

Question

I have the following scenario :-

• I do some query on a page using user input.
• User makes changes to the query and click 'Update' button
• User is redirected to a new page for confirmation where they are shown with old values and also the new ones
• Then user is asked to click 'Confirm'

The problem is that in the first page I did the query and the query results were stored in list, on 'Update' the list was copied into a new list, list data gets updated & user is directed to the confirmation page BUT now when the user is directed , I can't think of any way to pass both list to this new page.

I tried using the same apex controller for both pages BUT whenever I will get to the confirmation page the controller will be reloaded &its constructor will be called again & I will lose the data in the lists.

Can Someone Help me With THIS?

Answer 1

The page's view state is preserved when the following conditions hold:

• The new page uses the same controller as the old page.
• The new page uses a subset of the extensions as the old page.
• The Redirect flag is set to false on the PageReference.
• Both pages use an apex:form.

Here's an incredibly basic proof of concept that shows this behavior in action:

CommonController.cls

public class CommonController {
    public String message { get; set; }
    public PageReference nextPage() {
        return Page.CommonPage2;
    }
}

CommonPage1.page

<apex:page controller="CommonController">
    <apex:form>
        <h1>
            This is page 1.
        </h1>
        Enter a message:
        <apex:inputText value="{!message}" />
        <apex:commandButton action="{!nextPage}" value="Show on next page" />
    </apex:form>
</apex:page>

CommonPage2.page

<apex:page controller="CommonController">
    <apex:form>
        <h1>
            This is page 2.
        </h1>
        The message from page 1 was:
        <span style="font-weight: bold">
            <apex:outputText value="{!message}" />
        </span>
    </apex:form>
</apex:page>

---

As this code hopefully demonstrates, you can indeed pass whatever data you want between the two controllers. Depending on the complexity of the page, it might take you several tries, but I suggest that you simply start off simple (e.g. build a basic working version), and then build up to the desired feature set over several iterations.

Answer 2

I am assuming you are using pagereference method to navigate to the next page from controller.

PageReference nextpage = PageReference.orderpage;
nextpage.getParameters().put('items', String.join(items, ','));

and in the next page you can do a get of the parameter.