Nested ListView or Nested Repeater - winjs

Question

I am trying to created a nested repeater or a nested list view using WinJS 4.0, but I am unable to figure out how to bind the data source of the inner listview/repeater.
Here is a sample of what I am trying to do (note that the control could be Repeater, which I would prefer):
HTML:
<div id="myList" data-win-control="WinJS.UI.ListView">
<span data-win-bind="innerText: title"></span>
<div data-win-control="WinJS.UI.ListView">
<span data-win-bind="innerText: name"></span>
</div>
</div>
JS:
var myList = element.querySelector('#myList).winControl;
var myData = [
{
title: "line 1",
items: [
{name: "item 1.1"},
{name: "item 1.2"}
]
},
{
title: "line 2",
items: [
{name: "item 2.1"},
{name: "item 2.2"}
]
}
];
myList.data = new WinJS.Binding.List(myData);
When I try this, nothing renders for the inner list. I have attempted trying to use this answer Nested Repeaters Using Table Tags and this one WinJS: Nested ListViews but I still seem to have the same problem and was hoping it was a little less complicated (like KnockOut).
I know it is mentioned that WinJS doesn't support nested ListViews, but that seems to be a few years ago and I am hoping that is still not the issue.
Update
I was able to get the nested repeater to work correctly, thanks to Kraig's answer. Here is what my code looks like:
HTML:
<div id="myTemplate" data-win-control="WinJS.Binding.Template">
<div
<span>Bucket:</span><span data-win-bind="innerText: name"></span>
<span>Amount:</span><input type="text" data-win-bind="value: amount" />
<button class="removeBucket">X</button>
<div id="bucketItems" data-win-control="WinJS.UI.Repeater"
data-win-options="{template: select('#myTemplate')}"
data-win-bind="winControl.data: lineItems">
</div>
</div>
</div>
<div id="budgetBuckets" data-win-control="WinJS.UI.Repeater"
data-win-options="{data: Data.buckets,template: select('#myTemplate')}">
</div>
JS: (after the "use strict" statement)
WinJS.Namespace.define("Data", {
buckets: new WinJS.Binding.List([
{
name: "A",
amount: 5,
lineItems: new WinJS.Binding.List( [
{ name: 'test item1', amount: 50 },
{ name: 'test item2', amount: 25 }
]
)
}
])
})
*Note that this answers part of my question, however, I would really like to do this all after a repo call and set the repeater data source programmatically. I am going to keep working towards that and if I get it I will post that as the accepted answer.

Answer 1

The HTML Repeater control sample for Windows 8.1 has an example in scenario 6 with a nested Repeater, and in this case the Repeater is created through a Template control. That's a good place to start. (I discuss this sample in Chapter 7 of Programming Windows Store Apps with HTML, CSS, and JavaScript, 2nd Edition, starting on page 372, or 374 for the nested part.)
Should still work with WinJS 4, though I haven't tried it.

Answer 2

Ok, so I have to give much credit to Kraig because he got me on the correct path to getting this worked out and the referenced book Programming Windows Store Apps with HTML, CSS, and JavaScript, 2nd Edition is amazing.
The original issue was a combination of not using templates correctly (using curly braces in the data-win-bind attribute), not structuring my HTML correctly and not setting the child lists as WinJS.Binding.List data source. Below is the final working code structure to created a nested repeater when binding the data from code only:
HTML:
This is the template for the child lists. It looks similar, but I plan on add more things so I wanted it separate instead of recursive as referenced in the book. Note that the inner div after the template control declaration was important for me.
<div id="bucketItemTemplate" data-win-control="WinJS.Binding.Template">
<div>
<span>Description:</span>
<span data-win-bind="innerText: description"></span>
<span>Amount:</span>
<input type="text" data-win-bind="value: amount" />
<button class="removeBucketItem">X</button>
</div>
</div>
This is the main repeater template for the lists. Note that the inner div after the template control declaration was important for me. Another key point was using the "winControl.data" property against the property name of the child lists.
<div id="bucketTemplate" data-win-control="WinJS.Binding.Template">
<div>
<span>Bucket:</span>
<span data-win-bind="innerText: bucket"></span>
<span>Amount:</span>
<input type="text" data-win-bind="value: amount" />
<button class="removeBucket">X</button>
<div id="bucketItems" data-win-control="WinJS.UI.Repeater"
data-win-options="{template: select('#bucketItemTemplate')}"
data-win-bind="winControl.data: lineItems">
</div>
</div>
</div>
This is the main control element for the nested repeater and it is pretty basic.
<div id="budgetBuckets" data-win-control="WinJS.UI.Repeater"
data-win-options="{template: select('#bucketTemplate')}">
</div>
JavaScript:
The JavaScript came down to a few simple steps:
Getting the winControl
var bucketsControl = element.querySelector('#budgetBuckets').winControl;
Looping through the elements and making the child lists into Binding Lists - the data here is made up but could have easily came from the repo:
var bucketsData = selectedBudget.buckets;
for (var i = 0; i < bucketsData.length; i++) {
bucketsData[i].lineItems =
new WinJS.Binding.List([{ description: i, amount: i * 10 }]);
}
Then finally converting the entire data into a Binding list and setting it to the "data" property of the winControl.
bucketsControl.data = new WinJS.Binding.List(bucketsData);
*Note that this is the entire JavaScript file, for clarity.
(function () {
"use strict";
var nav = WinJS.Navigation;
WinJS.UI.Pages.define("/pages/budget/budget.html", {
// This function is called whenever a user navigates to this page. It
// populates the page elements with the app's data.
ready: function (element, options) {
// TODO: Initialize the page here.
var bindableBuckets;
require(['repository'], function (repo) {
//we can setup our save button here
var appBar = document.getElementById('appBarBudget').winControl;
appBar.getCommandById('cmdSave').addEventListener('click', function () {
//do save work
}, false);
repo.getBudgets(nav.state.budgetSelectedIndex).done(function (selectedBudget) {
var budgetContainer = element.querySelector('#budgetContainer');
WinJS.Binding.processAll(budgetContainer, selectedBudget);
var bucketsControl = element.querySelector('#budgetBuckets').winControl;
var bucketsData = selectedBudget.buckets;
for (var i = 0; i < bucketsData.length; i++)
{
bucketsData[i].lineItems = new WinJS.Binding.List([{ description: i, amount: i * 10 }]);
}
bucketsControl.data = new WinJS.Binding.List(bucketsData);
});
});
WinJS.UI.processAll();
}
});
})();