Virtual ComboBox

The virtual ComboBox acts like the regular ComboBox, but is based on the framework's virtual infrastructure.

Preview Image

Features

• Mouse and keyboard support.
• Items with plain text and/or icons
• Ellipsis: If the label does not fit into the widget's bounds an ellipsis (”...”) is rendered at the end of the label.
• Supports filtering, sorting, grouping, data binding and custom rendering like the Virtual List.

Mouse and keyboard behavior:

	keyboard	open drop-down	key down; key up;
		close drop-down	esc; enter
	mouse	open drop-down	click on arrow button
		close drop-down	click on item; click outside drop-down
drop-down closed	keyboard	select next	not possible
		select previous	not possible
		select first	not possible
		select last	not possible
	mouse	select next	not possible
		select previous	not possible
drop-down open	keyboard	select next	key down then enter
		select previous	key up then enter
		select first	page up then enter
		select last	page down then enter
	mouse	select next	click on item
		select previous	click on item
		wrap in list	no
		preselect	mouse over; key up; key down
		select drop-down item on open	yes, first item in the list which begins with value

Description

The qx.ui.form.VirtualComboBox is based on the virtual infrastructure. The virtual SelectBox has both a TextField and a Virtual List drop-down. The drop-down can be used to predefine values which the user can select.

Using the virtual infrastructure has considerable advantages when there is a huge amount of model items to render: Widgets are created only for visible items and reused. This saves both creation time and memory.

The virtual ComboBox uses the same qx.ui.list.core.IListDelegate interface as the Virtual List to configure the ComboBox's behavior (item and group renderer configuration, filtering, sorting, grouping, etc.).

Note

At the moment we only support widget based rendering for list and group items, but we are planning to also support HTML based rendering in a future release.

Code Example

Here's an example. We create a simple ComboBox example with 2500 items, sorting the items (ascending) and log each value change.

//create the model data
var rawData = [];
for (var i = 0; i < 2500; i++) {
  rawData[i] = "Item No " + i;
}
var model = qx.data.marshal.Json.createModel(rawData);

//create the SelectBox
var comboBox = new qx.ui.form.VirtualComboBox(model);

//configure the ComboBox's behavior
var delegate = {
  sorter : function(a, b) {
    return a > b ? 1 : a < b ? -1 : 0;
  }
};
comboBox.setDelegate(delegate);

//log value changes
comboBox.addListener("changeValue", function(e) {
  this.debug("Value: " + e.getData());
}, this);

Demos

Here are some links that demonstrate the usage of the widget:

• ComboBox demo

API

Here is a link to the API of the widget:

qx.ui.form.VirtualComboBox