ComboView.ts

class ComboView extends Marionette.ItemView<ComboField>
{
	/**
	 * Constructor logic for ComboView.
	 * @param {ComboField} model The model for the ItemView.
	 */
	constructor(model: ComboField)
	{
		this.ui = {
			control: ".control-field input"
		};

		this.listenTo(model, "change:value", () => this.updateDisplay());

		super({model: model});
	}

	/**
	 * Update the display to reflect the backing value.
	 */
	protected updateDisplay(): void
	{
		// Get the kendo object
		let combobox = (this.ui.control as JQuery).data("kendoComboBox"); // Returns undefined

		let test = (this.ui.control as JQuery).data("test"); // Also undefined

		combobox.select(this.model.value.index);
	}

	/**
	 * Triggered after the view has been rendered
	 * Should do any post-rendering manipulation of el here
	 */
	public onRender(): void
	{
		// Make the field a kendo component
		(this.ui.control as JQuery).kendoComboBox();

		// Try adding another data value
		(this.ui.control as JQuery).data("test", "test");

		this.updateDisplay();
	}
}