Combobox

A combo box, combo box ( combo box of English ) or combo box is a data field in a graphical user interface (GUI ) of a computer software to make about which the user a selection from preset options or alternatively make your own inputs. The name combobox derives from the fact that they called as a combination of a text box (text box ) and a list box ( drop-down list, list box, drop- down menu ), and combo box, can be considered. In a combo box are therefore optional keystrokes in the text box the combobox impossible or if the selection / change one of the preset list entries. A combo box has an impact at an output field. Combo boxes are not to be confused with a select box or a drop-down list - this usually allow no free user input, the component of the text field that is missing here.

Operation and design

Which entries - as proposals for selection by the user - are displayed at what time in the list of the combo box depends on the particular application. From the implementation details of the combo box into a computer program, it also depends on whether the visible text field is initially empty, or if a default value is displayed. The list itself may initially be empty, and fill later with the numbers or text entered in the text field.

When combined with the TextField listbox is mostly a space-saving, one-line special drop -down listbox, which only shows up when you press the corresponding button. Strictly speaking, this is called a drop-down combo box. A combination of combo box, button (button) and icon is also called Combutcon.

Application Examples

  • Database Applications: For managing an address database, for example, offers a combo box for the address. The default values ​​are ' Mr., Mrs., Company ', in addition, the processor also has however the possibility to enter specially defined styling (about Dr. ).
  • Address bar of a web browser: A typical example of a combobox is the address bar of a web browser. The Internet address can be entered in the text box already visited pages found in the drop-down list from the user space and can with little effort be called again.
  • Web applications: Using Ajax realized auto- completes are realized with a combo box: The user types something into a text box, followed by a list of suggested terms opens, from which the user can choose.
  • Relationships between data objects: If is about to enter in a data entry screen for orders, inter alia, what agents is responsible for processing, a combo box is often used. The ' unfolded ' box shows the names of possible input selection clerk at ( from a corresponding dataset ). After selection (and if the order data is displayed only ) is just the name of the selected agent's visible; whose identifier is stored in the record of the respective order.

Implementation

HTML

Unlike HTML 4 HTML5 provides the ability to define a list:

 

Java

In the Java Swing JComboBox is under the combobox GUI component.

If the JComboBox as a non- editable programmed ( setEditable ( false)), it behaves like a drop-down list box, as well as the AWT Choice component. But not as a separate drop-down list box, but it is a " castrated " JComboBox uses - Sun provides the multiline listbox in Swing JList to.

MS Access

In the graphical development environment of MS Access, the combo box is used ( in the example of 'Job' ) is applied as the element type ' combo box ' and as shown in the graph on the entry form. The developer specifies in this case (for data display from a database ) for the combo box include the following properties: width of the box; Number of lines of the box; Data source for the persons to be displayed; Name of the ID in the dataset PERSON; Name of the foreign key in the database CONTRACT uva

Credentials

  • Graphical User Interface
Computer icon Abstract Window Toolkit
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