How to pass list view selected items from one visualforce page to another

Question

So I have a custom object called Transactions, and have recently made a list view button that will redirect the user to a visualforce page that will show the selected record, and provide a few buttons to allow the user to select different report types to create. These reports I will be using visualforce pages as well, and have run into an issue when trying to use the same custom controller.

The first visualforce page is called LCD_Report_Selection and uses a custom controller LCD_Report_Selection_Controller. The basic page and controller I have made so far is as follows ***ignore the registry part, was a potential solution I found online that was not working **** :

<apex:page standardController="LCD_Transaction__c" extensions="LCD_Report_Selection_Controller" recordSetVar="transactions">

<apex:pageBlock >
    <apex:pageBlockTable value="{!selected}" var="trans">
        <apex:column value="{!trans.id}"/>
        <apex:column value="{!trans.Transaction_Name__c}"/>
        <apex:column value="{!trans.Issuer_Name__c}"/>
    </apex:pageBlockTable>

    <div align="center">


    <apex:form >
    <table>
        <tr>
            <td>
                <apex:commandButton value="Pipeline Report" /> 
            </td>
            <td>
                <apex:commandButton value="Broad Pipeline Report" action="{!Broad_Pipeline}" /> 
            </td>
        </tr>
        <tr>
            <td>
                <apex:commandButton value="Long Comps Output" /> 
            </td>
            <td>
                <apex:commandButton value="Long Comps Output by Tranche" />                                     
            </td>
        </tr>
    </table>
    </apex:form>
        </div>


</apex:pageBlock>

public class LCD_Report_Selection_Controller {

public List<LCD_Transaction__c> transactions {get;set;}

private Registry r;

public LCD_Report_Selection_Controller(ApexPages.StandardSetController controller){
    List<LCD_Transaction__c> transactions = New List<LCD_Transaction__c>();
    transactions = controller.getSelected();
    saveTransactions(transactions);

    r = Registry.instance();
    r.add(LCD_Report_Selection_Controller.class, this);

    system.debug('transactions --- ' + transactions);
    system.debug('std set controller');
}


public void saveTransactions(List<LCD_Transaction__c> trans){
    transactions = trans;
}

public PageReference Broad_Pipeline(){

    PageReference report = Page.LCD_Broad_Pipeline_Report;
    report.setRedirect(true);
    return report;

}

}

What I am trying to achieve is when I press the broad pipeline report button, I would like to take the selected records and process them in a table on a seperate visualforce page. The issue I am running into is that since both pages use the same controller, when the second page is rendered it creates a new controller and does not have the selected transactions. I am attempting to create a second controller extension and pass a list of transactions to it, but have not been successful. What would be the best way to go about passing the transactions to the second visual forcepage? see below

<apex:page standardController="LCD_Transaction__c" extensions="LCD_Report_Selection_Controller" recordSetVar="LCDtransactions" renderAs="pdf" >

<apex:pageBlock>
    <apex:pageBlockSection>
        <apex:pageBlockTable value="{!transactions}" var="trans">
            <apex:column value="{!trans.TransBreakDate__c}"/>
            <apex:column value="{!trans.Issuer_Name__c}" />
            <apex:column value="{!trans.TransSponsorName__c}" />
            <apex:column value="{!trans.Issuer_Industry__c}" />

        </apex:pageBlockTable>
    </apex:pageBlockSection>
</apex:pageBlock>

Answer 1

Changing setRedirect(true) to setRedirect(false) may solve your problem.

One technique is to pass a command-line parameter containing the Id values in a comma-separated format. The first page sets the parameter and the second page reads the parameter and queries the corresponding records.

On the write side:

String[] ids = new String[] {};
for (LCD_Transaction__c t : transactions) ids.add(t.Id);

PageReference report = Page.LCD_Broad_Pipeline_Report;
report.getParameters().put('ids', String.join(ids, ','));
report.setRedirect(true);
return report;

On the read side:

String[] ids;
String s = ApexPages.currentPage().getParameters().get('ids');
if (s != null) ids = s.split(',');
else ids = new String[] {};