Display Relationships Between Lists on Visualforce Page

Question

I have a list of strings.

I am using these strings to populate three other object lists by querying for this string.

For every iteration I am adding the lists populated to a List of lists. Ex: First populate a case list where field__c = string[i], once populated add this list to a List<List<Case>>.

How should I relate these lists to each other so that I can display the information in datatable with columns that have datatables?

For example:

DATATABLE[
 - Column 1: String[i] 
 - Column 2: DATATABLE [ listOfList1[i].list1 ]
 - Column 3: DATATABLE [ listOfList2[i].list2 ]
]

I understand how to use to display list of list information in a datatable, but apex:repeat iterates through all of the lists in the listOfList.

I believe the solution lies in relating or mapping these lists, but I am unable conceptualize how that would work.

UPDATE:

I'm still stuck, but created a generic container object that I can store all of these lists/variables in and created a list for the generic object, but still unsure of how to output the variables within that object onto the VFP, particularly the lists.

Answer 1

Since Visualforce can only display your data in a row-by-row process (kind of like a dot matrix printer), you have to build the rows yourself using a wrapper object and extracting the values from your separate lists.

It sounds like you have lists of objects to display, so that wrapper would be like this:

public class RowData {
    public Case theCase { get; set; }
    public MyObj1__c obj1 { get; set; }
    public MyObj2__c obj2 { get; set; }

    public RowData() {}
}

For each category, you do an integer loop based on the largest list size, and build each wrapper row. Say you are building the Level 1 category:

List<RowData> rowsLevel1 = new List<RowData>();
Integer max; // set to the size of largest list for the category;
for (Integer i = 0; i < max; i++) {
    RowData theRow = new RowData();
    theRow.theCase = (caseList.size() > i ? caseList[i] : new Case());
    theRow.obj1 = (obj1List.size() > i ? obj1List[i] : new MyObj1__c());
    theRow.obj2 = (obj2List.size() > i ? obj2List[i] : new MyObj2__c());
    rowsLevel1.add(theRow);
}

If one list is longer than the others, then the column fields of the other lists must be blank.

To organize all these rows, you use a map of wrapper lists keyed on your category values:

Map<String, List<RowData>> allRows = new Map<String, List<RowData>>();
allRows.add('Level 1', rowsLevel1);

Then you can use nested repeats in your Visualforce page to display all rows grouped by category:

<apex:repeat value="{!allRows}" var="category">
    <apex:repeat value="{!allRows[category]}" var="theRow">
        <apex:column>{!category}</apex:column>
        <apex:column>{!theRow.theCase.Subject}</apex:column>
        <apex:column>{!theRow.obj1.Field1__c}</apex:column>
        <apex:column>{!theRow.obj2.Field2__c}</apex:column>
    </apex:repeat>
</apex:repeat>