## Combo

### Description

The Combo class implements the Combo object, a drop-down menu (or list-box) with an optional edit field.

The `style` property defines the type of combo box, as follows:

     0 = drop down menu with edit field
     1 = simple list box (always down), with edit field
     2 = drop down list, no edit field

Note: Under MacOS, only style 2 is currently supported. Under Linux, style 1 is not supported.

The `list` property determines the items in the menu/list box part of the control. You can set it either as a character matrix or as a character vector with embedded carriage returns. (If you read it back, it will be returned as a character matrix).

Under Windows amd Linux, the `text` property contains the text of the edit field (which the user may have edited), as a character vector. The `selection` and `seltext` properties contain the selection start/end and selected text in the edit field. Under Windows only, the `limit` property allows you to limit the maximum number of characters in this text.

The `value` property is an integer containing the index into the list of the selected item, in index origin 1. It is an empty vector if there is no selection (you can also write 0 to achieve the same effect).

To provide help text when the user moves the mouse pointer over the control and pauses, you can use the `tooltip` property.

If you need to detect when the user changes the selection, add an `onChange` callback.

### Example

         ’DEMO_Combo;DEMO
    [1]   © Sample function demonstrating use of the Combo object
    [2]   DEMO„'Ś' ŚNEW 'Dialog' Ş DEMO.scale„1
    [3]   DEMO.title„'Combo Example'
    [4]   DEMO.myCombo.New 'Combo' Ş DEMO.myCombo.where„2 1
    [5]   DEMO.myCombo.list„ŚW Ş DEMO.myCombo.value„3
    [6]   © Wait for the user to close the window
    [7]   0 0˝ŚWE DEMO
         ’

### Properties

align anchors aquaadjust autodraw caption children class color data doublebuffered dragsource droptarget enabled events extent font handle limit list maxsize methods minsize name opened order pointer properties scale selection self seltext size sourceformats style tabstop targetformats text tie tooltip units value visible where winptr

### Methods

Click Clienttoscreen Close Create Delete Draw Focus Hide New Open Paint Resize Screentoclient Send Set Show Trigger

### Callbacks

onChange onClick onClose onDblClick onDestroy onDragDrop onDragEnd onDragEnter onDragLeave onDragOver onDragStart onFocus onHide onKeyDown onKeyPress onKeyUp onMouseDown onMouseMove onMouseUp onOpen onSend onShow onUnFocus

Topic: APLX Help : System Classes : List of Classes : Combo

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