[merlight]

I tried to write some untested code for illustration. Careful with dot where colon should be -- control:GetParent()

edit: or look at LAM controls, they too have custom data:
control.panel is the panel it's contained in
control.data is the optionData it was created from

<Control name="EventExplorerRow" virtual="true">
    <Dimensions y="45"/>
    <Controls>
        <Label name="$(parent)Id" font="ZoFontGame" horizontalAlignment="RIGHT">
            <Anchor point="RIGHT" relativePoint="LEFT" offsetX="50"/>
        </Label>
        <Label name="$(parent)Name" font="ZoFontGame">
            <!-- I don't know how, but it's definitely possible to make this clickable,
                 so that you can enable/disable events by cliking on the name (see "ZO_CheckButtonLabel") -->
            <Anchor point="LEFT" relativeTo="$(parent)Id" relativePoint="RIGHT" offsetX="20"/>
        </Label>
    </Controls>
</Control>

function EventExplorer:createRows()
    local function onRowClicked(...)
        self:onRowClicked(...)
    end
    self.rows = {}
    for i = 1, NUM_PAGE_ROWS do
        local row = CreateControlFromVirtual("$(parent)Row", self.pageScrollWindow, "EventExplorerRow", i)
        row.data = {}
        row:SetHandler("OnClicked", onRowClicked)
        table.insert(self.rows, row)
    end
end
 
function EventExplorer:onRowClicked(control, button)
    -- this handler should be usable for both labels and even the parent row control
    -- (which I think will be useful so that cliking in the empty space between labels works)
    local row
    if control.data then
        row = control
    else
        row = control:GetParent()
    end
    local status = self:toggleEventEnabled(row.data.eventId)
    row:SetEnabled(status)
end

-- this method will be used to fill the page with event ids and labels;
-- you'd store all event ids returned from a filter in self.selectedEventIds;
-- after the search you'd fill the 1st page with self:setPage(1);
-- if there are more events than NUM_PAGE_ROWS, and you provide
-- a control for switching to the next page, it can call self:setPage(self.currentPage);
function EventExplorer:setPage(pageNumber)
    local offset = math.min(0, pageNumber - 1) * NUM_PAGE_ROWS
    for i, row in ipairs(self.rows) do
        local eventId = self.selectedEventIds[i + offset]
        local idLabel = row:GetNamedChild("Id")
        local nameLabel = row:GetNamedChild("Name")
        row.data.eventId = eventId
        if eventId then
            idLabel:SetText(tostring(eventId))
            nameLabel:SetText(self:getEventName(eventId))
            nameLabel:SetEnabled(self:isEventEnabled(eventId))
        else
            idLabel:SetText("")
            nameLabel:SetText("")
            nameLabel:SetEnabled(false)
        end
    end
end
 
-- toggleEventEnabled, isEventEnabled will work with an internal table
-- that will keep track of what events you have registered