# combobox - Create and manipulate combination box widgets

## SYNOPSIS

combobox pathName ?options?

## INHERITANCE

itk::Widget <- LabeledWidget <- Entryfield <- Combobox

## STANDARD OPTIONS

cursor
highlightColor
insertWidth
insertWidth
selectBorderWidth

justify
highlightThickness
insertBackground
insertBorderWidth
textVariable

background
exportSelection
relief
insertOffTime
selectForeground

borderWidth
foreground
width
insertOnTime
selectBackground

See the "options" manual entry for details on the standard options.

## ASSOCIATED OPTIONS

hscrollmode | textBackground | textFont | vscrollmode

See the "scrolledlistbox" manual entry for details on the above inherited options.

show |  |  |

See the "entry" manual entry for details on the above inherited option.

## INHERITED OPTIONS

childSitePos invalid | command textBackground | fixed textFont | focusCommand validate

See the "entryfield" class manual entry for details on the inherited options.

labelBitmap labelPos | labelFont labelText | labelImage labelVariable | labelMargin

See the "labeledwidget" class manual entry for details on the inherited options.

## WIDGET-SPECIFIC OPTIONS

    Name:                   arrowRelief
    Class:                  Relief
    Command-Line Switch:	-arrowrelief

Specifies the relief style to use for a dropdown Combobox's arrow button in a normal (not depressed) state. Acceptable values are raised, sunken, flat, ridge, and groove. Sunken is discouraged as this is the relief used to indicate a depressed state. This option has no effect on simple Comboboxes. The default is raised.

    Name:                   completion
    Class:                  Completion
    Command-Line Switch:	-completion

Boolean given in any of the forms acceptable to Tcl_GetBoolean which determines whether insertions into the entry field, whether from the keyboard or programmatically via the insert method, are automatically completed with the first matching item from the listbox. The default is true.

    Name:                   dropdown
    Class:                  Dropdown
    Command-Line Switch:	-dropdown

Boolean describing the Combobox layout style given in any of the forms acceptable to Tcl_GetBoolean. If true, the Combobox will be a dropdown style widget which displays an entry field and an arrow button which when activated will pop up a scrollable list of items. If false, a simple Combobox style will be used which has an entry field and a scrollable list beneath it which is always visible. Both styles allow an optional label for the entry field area. The default is true.

    Name:                   editable
    Class:                  Editable
    Command-Line Switch:	-editable

Boolean describing whether or not the text entry area is editable by the user. If true the user can add items to the combobox by entering text into the entry area and then pressing Return. If false, the list of items is non-editable and can only be changed by calling the insert or delete methods. (The value in the entry field can still be modified by selecting from the list.) Given in any of the forms acceptable to Tcl_GetBoolean. The default is true.

    Name:                   grab
    Class:                  Grab
    Command-Line Switch:	-grab

This option sets the grab scope for the appearance of the listbox in drop-down comboboxes. It can be either global or local. The default is local.

    Name:                   listHeight
    Class:                  Height
    Command-Line Switch:	-listheight

Height of the listbox specified in any of the forms acceptable to Tk_GetPixels. The default is 150 pixels.

    Name:                   margin
    Class:                  Margin
    Command-Line Switch:	-margin

Specifies the width in pixels between the entry component and the arrow button for a dropdown Combobox given in any of the forms acceptable to Tk_GetPixels. This option has no effect on a simple Combobox. The default is 1.

    Name:                   popupCursor
    Class:                  Cursor
    Command-Line Switch:	-popupcursor

Specifies the cursor to be used for dropdown style listboxes. The value may have any of the forms acceptable to Tk_GetCursor. The default is arrow.

    Name:                   selectionCommand
    Class:                  SelectionCommand
    Command-Line Switch:	-selectioncommand

Specifies a Tcl command procedure which is called when an item in the listbox area is selected. The item will be selected in the list, the listbox will be removed if it is a dropdown Combobox, and the selected item's text will be inserted into the entry field before the -selectioncommand proc is called. The default is {}.

    Name:                   state
    Class:                  State
    Command-Line Switch:	-state

Specifies the overall state of the Combobox megawidget. Can be either normal or disabled. If the Combobox is disabled, no text can be entered into the entry field, no selection can be made in the listbox, and the arrowBtn component is disabled. The default is normal.

    Name:                   unique
    Class:                  Unique
    Command-Line Switch:	-unique

Boolean describing whether or not duplicate items are allowed in the combobox list. If true, then duplicates are not allowed to be inserted. If false, a duplicate entry causes selection of the item. Given in any of the forms acceptable to Tcl_GetBoolean. The default is true.

## DESCRIPTION

The combobox command creates an enhanced entry field widget with an optional associated label and a scrollable list. When an item is selected in the list area of a Combobox, its value is then displayed in the entry field text area. Functionally similar to an Optionmenu, the Combobox adds (optional) list scrolling and (optional) item editing and inserting capabilities.

There are two basic styles of Comboboxes (determined by the -dropdown option): dropdown and simple. The dropdown style adds an arrow button to the right of the entry field which when activated will pop up (and down) the scrolled listbox beneath the entry field. The simple (non-dropdown) Combobox permanently displays the listbox beneath the entry field and has no arrow button. Either style allows an optional entry field label.

## METHODS

The combobox command creates a new Tcl command whose name is pathName. This command may be used to invoke various operations on the widget. It has the following general form:

    pathName option ?arg arg ...?

Option and the args determine the exact behavior of the command. The following commands are possible for Combobox widgets:

## ASSOCIATED METHODS

icursor | scan |  |

See the "entry" manual entries for details on the above associated methods.

curselection xview | index yview | see | size

See the "listbox" manual entries for details on the above associated methods.

getcurselection | justify | sort |

See the "scrolledlistbox" manual entries for details on the above associated methods.

## WIDGET-SPECIFIC METHODS

pathName cget option
  Returns the current value of the configuration option given by option. Option may have any of the values accepted by the combobox command.

pathName clear ?component?
  Clears the contents from one or both components. Valid component values are list, or entry. With no component specified, both are cleared.

pathName configure ?option? ?value option value ...?
  Query or modify the configuration options of the widget. If no option is specified, returns a list describing all of the available options for pathName (see Tk_ConfigureInfo for information on the format of this list). If option is specified with no value, then the command returns a list describing the one named option (this list will be identical to the corresponding sublist of the value returned if no option is specified). If one or more option-value pairs are specified, then the command modifies the given widget option(s) to have the given value(s); in this case the command returns an empty string. Option may have any of the values accepted by the combobox command.

pathName delete component first ?last?
  Delete one or more elements from a given component, list or entry. If a list item to be removed is currently selected (displayed in the entry field area), the entry field will be cleared.

pathName get ?index?
  With no arguments, returns the contents currently in the entry field area. With a single argument, returns the contents of the listbox item at the indicated index.

pathName insert component index element ?element element ...?
  Insert one or more new elements into the given component, list or entry, just before the element given by index.

pathName selection option first ?last?
  Adjust the selection within the listbox component and updates the contents of the entry field component to the value of the selected item. See the "listbox" manual entry for more details on parameter options.

## COMPONENTS

    Name:                   entry
    Class:                  Entry

Text entry area where the current selection is displayed. If the Combobox is editable and its state is normal, the user can edit the contents of this item.

    Name:                   list
    Class:                  Scrolledlistbox

Scrollable list which stores all the items which the user can select from. For dropdown Comboboxes, this component is hidden until the user pops it up by pressing on the arrow button to the right of the entry component. For simple Comboboxes this component is always visible just beneath the entry component.

## DEFAULT BINDINGS

The Combobox generally has the same bindings as its primary component items - the Scrolledlistbox and Entryfield. However it also adds these:

[1] Button-1 mouse press on the arrow key of a dropdown Combobox causes the list to be popped up. If the combobox is non-editable, a Button-1 press on the entry field area will also pop up the list.

[2] Button-1 mouse press anywhere on the display removes a dropdown listbox which has been popped up, unless the keypress is upon one of the Combobox scrollbars which scrolls the list. If it is pressed upon an item in the list area, that item will be selected before the list is removed.

[3] Button-3 mouse press on the arrow key of a dropdown Combobox causes the next item to be selected. Shift-Button-3 causes the previous item to be selected.

[4] Escape keypress removes a dropdown list which has been popped up.

[5] The <space> and <Return> keystrokes select the current item. They also remove the popped up list for dropdown comboboxes.

[6] Up and Down arrow keypresses from the entry field and arrow button component cause the previous and next items in the listbox to be selected respectively. Ctl-P and Ctl-N are similarly mapped for emacs emulation.

[7] Entry field and arrow button component Shift-Up and Shift-Down arrow keys pop up and down the listbox of a dropdown Combobox. The arrow button component also maps <Return> and <space> similarly.

## EXAMPLE

     proc selectCmd {} {
        puts stdout "[.cb2 getcurselection]"
     }

     #
     # Non-editable Dropdown Combobox
     #
     combobox .cb1 -labeltext Month: \\
         -selectioncommand {puts "selected: [.cb1 getcurselection]"} \\
         -editable false -listheight 185 -popupcursor hand1
     .cb1 insert list end Jan Feb Mar Apr May June Jul Aug Sept Oct Nov Dec

     #
     # Editable Dropdown Combobox
     #
     combobox .cb2 -labeltext "Operating System:" -selectioncommand selectCmd
     .cb2 insert list end Linux HP-UX SunOS Solaris Irix
     .cb2 insert entry end L

     pack .cb1 -padx 10 -pady 10 -fill x
     pack .cb2 -padx 10 -pady 10 -fill x

## ORIGINAL AUTHOR

John S. Sigler

## CURRENT MAINTAINER

Mitch Gorman (logain@erols.com)

## KEYWORDS

combobox, entryfield, scrolledlistbox, itk::Widget, entry, listbox, widget, iwidgets