Dynamically display fields based on Picklist for create page

Question

I have a requirement to build a page that displays a different set of fields based on the value in picklist that I have on the page as an inputfield. I have this working for both the detail page, and my original solution for the edit page when working with an existing record already in context. However, it does not work when creating a new record. The visibility checks all come out to false, so nothing gets displayed, even if the proper product is selected in the picklist.

Here is my latest attempt -

Controller Code:

public with sharing class NewRequestExtension {
    private ApexPages.StandardController controller {get; set;}
    public New_Request__c record {get; set;}
    public list<New_Request__c> typeOfProduct {get; set;}
    public Boolean fieldSet1Visibility {get; set;}
    public Boolean fieldSet2Visibility {get; set;}
    public Boolean fieldSetVisibility {get; set;}
    public string productSelection {get;set;}
    public string productType {get;set;}

public NewRequestExtension(ApexPages.standardController controller){
        this.controller = controller;
        this.record = (New_Request__c)controller.getrecord();
    }

public PageReference setEditVisibility() {

        fieldset1Visibility = FALSE;
        fieldset2Visibility = FALSE;
        fieldset3Visibility = FALSE;

        if(record.Type_of_Product__c != null) {
            productType = record.Type_of_Product__c;
        } else {
            productType = productSelection;
        }


        if (productType == 'Product1' {

                fieldset1Visibility = TRUE;
        } else if (productType == 'Product 2' {

                fieldset2Visibility = TRUE;
        } else if (productType == 'Product 3' {

                fieldset3Visibility = TRUE;
        }

        return null;
    }

And here is my Visualforce code:

<apex:page StandardController="New_Request__c" extensions="NewRequestExtension" action="{!setEditVisibility}" >
    <apex:form >
        <apex:pageBlock title="New Request Edit" mode="edit" >
            <apex:pageBlockButtons >
                <apex:commandButton action="{!save}" value="Save" />
                <apex:commandButton action="{!saveandnew}" value="Save And New" />
                <apex:commandButton action="{!cancel}" value="Cancel" />
            </apex:pageBlockButtons>
            <apex:actionRegion >
                <apex:pageBlockSection title="Information" >
                        <apex:inputField value="{!New_Request__c.Type_of_Product__c}" >
                <apex:actionSupport id="productType" event="onchange" action="{!setEditVisibility}" rerender="productInfo" immediate="TRUE" >
                    <apex:param name="TypeSelection" value="{!New_Request__c.Type_of_Product__c}" assignTo="{!productSelection}" />
                </apex:actionSupport>
                </apex:inputField>
            </apex:pageBlockSection>
            </apex:actionRegion>
          <apex:outputPanel id="productInfo" >
            <apex:pageBlockSection title="Product Information" id="product1Section" rendered="{!fieldset1Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset1}" var="fieldset1">
                    <apex:inputField value="{!New_Request__c[fieldset1]}" />
                </apex:repeat>
            </apex:pageBlockSection>
            <apex:pageBlockSection title="Product Information" id="product2section" rendered="{!fieldset2Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset2}" var="fieldset2">
                    <apex:inputField value="{!New_Request__c[fieldset2]}" />
                </apex:repeat>
            </apex:pageBlockSection>
            <apex:pageBlockSection title="Product Information" id="product3section" rendered="{!fieldset3Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset3}" var="fieldset3">
                    <apex:inputField value="{!New_Request__c[fieldset3]}" />
                </apex:repeat>
            </apex:pageBlockSection>
        </apex:outputPanel>
</apex:pageBlock>
    </apex:form>
</apex:page>

Answer 1

I don't think you need the apex:parameter here. I'd also change the inputField value to refer to the local "record" instead of the standard controller "New_Request__c" since that's the one you refer to in your setEditVisibility method (

<apex:inputField value="{!record.Type_of_Product__c}" >
    <apex:actionSupport id="productType" event="onchange" action="{!setEditVisibility}" rerender="productInfo" immediate="TRUE" />
</apex:inputField>

Then within the setEditVisibility method, I'd remove the if/then and instead just set the parameter. Replace this...

if(record.Type_of_Product__c != null) {
    productType = record.Type_of_Product__c;
} else {
    productType = productSelection;
}

... with this...

productType = record.Type_of_Product__c;

Answer 2

I changed the constructor up to get the current records value if an edit, or to put a default selection if a new record. Then put in a method for getting the picklist values to populate the selectList and update the save action to make sure Type_Of_Product__c picks up the changes made:

public NewRequestExtension(ApexPages.standardController controller){
        this.controller = controller;
        this.record = (New_Request__c)controller.getrecord();

        if(record.Type_of_Product__c != null) {
        productType = record.Type_of_Product__c;
    } else {
        productType = 'Product1'; //default value for New records
    }
 }

    public list<selectOption> getProducts(){

        list<selectOption> options = new list<selectOption>();
        list<Schema.PicklistEntry> values =
         New_Request__c.Type_of_Product__c.getDescribe().getPickListValues();

        for (Schema.PicklistEntry a : values)
      { 
         options.add(new SelectOption(a.getLabel(), a.getValue())); 
      }

      return options;
    }

    public PageReference save() {

        this.record.Type_of_Product__c = productType;
        return controller.save();
    }

Updated Visualforce page:

<apex:page StandardController="New_Request__c" extensions="NewRequestExtension" action="{!setEditVisibility}" >
    <apex:form >
        <apex:pageBlock title="New Request Edit" mode="edit" >
            <apex:pageBlockButtons >
                <apex:commandButton action="{!save}" value="Save" />
                <apex:commandButton action="{!saveandnew}" value="Save And New" />
                <apex:commandButton action="{!cancel}" value="Cancel" />
            </apex:pageBlockButtons>
           <apex:outputPanel id="productInfo" >
            <apex:actionRegion >
                <apex:pageBlockSection title="Product Selection" >
                        <apex:selectList label="Type of Product" multiselect="false" size="1" value="{!ProductType}" >
                        <apex:selectOptions value="{!Products}" />
                    <apex:actionSupport id="productType" event="onchange" action="{!setEditVisibility}" rerender="productInfo" />
                </apex:selectList>
            </apex:pageBlockSection>
            </apex:actionRegion>
            <apex:pageBlockSection title="Product Information" id="product1Section" rendered="{!fieldset1Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset1}" var="fieldset1">
                    <apex:inputField value="{!New_Request__c[fieldset1]}" />
                </apex:repeat>
            </apex:pageBlockSection>
            <apex:pageBlockSection title="Product Information" id="product2section" rendered="{!fieldset2Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset2}" var="fieldset2">
                    <apex:inputField value="{!New_Request__c[fieldset2]}" />
                </apex:repeat>
            </apex:pageBlockSection>
            <apex:pageBlockSection title="Product Information" id="product3section" rendered="{!fieldset3Visibility}" >
                <apex:repeat value="{!$ObjectType.New_Request__c.FieldSets.fieldset3}" var="fieldset3">
                    <apex:inputField value="{!New_Request__c[fieldset3]}" />
                </apex:repeat>
            </apex:pageBlockSection>
        </apex:outputPanel>
</apex:pageBlock>
    </apex:form>
</apex:page>