ListAdd (Function)

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Ayuda / WLanguage / Funciones WLanguage / Controles, páginas y ventanas / Funciones List Box

List Boxes containing more than 10 000 elements
Visibility/Invisibility of elements in a List Box or Combo Box control
Equivalence
Sorted/Unsorted List Box control
Customizing the elements found in a List Box or Combo Box control
Tabulations: Multi-element List Box control
Adding an element to the browser
Miscellaneous

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ListAdd (Function)

Adds an element to:

a List Box control populated programmatically,
a ListView control populated programmatically,
a Carousel control,
a Combo Box control populated programmatically.

Remarks:

To add an element at a specific position, use ListInsert.
ListAdd can be used on the single-selection and multi-selection List Box controls.
To add an image to a standard List Box control, use gImage.
To add elements to a Combo Box control found in a container column of a Table control, use Content.

Attention: The element will only be added to the page displayed in the browser.. For more details, see Remarks.

Ejemplo

// Add the customer named "Moore" into "LIST_CustomerList"
ListAdd(LIST_CustomerList, "Moore")

// Add the customers named "Clark" and "Smith" into "LIST_CustomerList"
ListAdd(LIST_CustomerList, "Clark" + CR + "Smith")

// Add the "C:\MyImages\CoralReef.JPG" image into the "LSV_Diving" listview control
// The caption of this image will be "Nice coral"
ListAdd(LSV_Diving, "Nice coral", "C:\MyImages\CoralReef.JPG")

// The "COMBO_Title" Combo Box displays personal titles:
// "Mister", "Madam" and "Miss".
// An integer representing a gender will be returned to the language.
ListeAdd(COMBO_Title, "Mister" + gStoredValue("1"))

Sintaxis

<Result> = ListAdd(<Control to use> [, <Element> [, <Path of image to display>]])

<Result>: Boolean

True if the element was added,
False otherwise.
ListAdd returns no result.

<Control to use>: Control name

Name of control to use:
List Box control populated programmatically,
ListView control populated programmatically,
Combo Box control populated programmatically.
If this parameter corresponds to an empty string (""), the element is added to the List Box control (or Combo Box) to which the current event belongs.
The name of the List Box (or Combo Box) control to use must be specified.

<Element>: Optional character string

Element that will be added into the specified control. If this parameter is not specified, an empty row is added into the List Box or Combo Box control.
This parameter can contain:
Carriage Return characters (CR) to add several elements.
tabs (TAB) to obtain a multi-element List Box control (see Notes).
gStoredValue to indicate the value that will be returned when the element is selected.
For a Carousel control, the content of this parameter is displayed in the upper-left corner of the Carousel control.
For a ListView control, this parameter corresponds to the image caption. This parameter can contain Carriage Return characters (CR) to add several elements. In this case:
if <Path of image to display> is not specified, the added elements will be associated with the default image (defined in the "Details" tab of the description window of control).
if <Path of image to display> is specified, only the first element will be added. This element will be associated with the specified image.
The Carriage Return characters (CR) are supported while the tabulations (TAB) are not supported.
To add several consecutive spaces, use non-breaking spaces: Caract(160).

<Path of image to display>: Optional character string

Name and path of image that will be added into a ListView control. You can also use an image memo field or a Image type variable.
This parameter is taken into account for ListView controls displayed in ListView mode only.
If this parameter is not specified, the default image (defined in the "Detail" tab of the control description window) is used..
This parameter is not available.

Observaciones

List Boxes containing more than 10 000 elements

The maximum number of elements contained in a List Box control is limited only by available RAM (theoretical maximum: 2 billion lines). Nevertheless, filling a List Box control with an important number of elements (more than 10 000) affects performance

To add many elements to a List Box control, it is recommended to use a List Box control based on a data file (i.e., a list directly linked to an HFSQL data file).

Visibility/Invisibility of elements in a List Box or Combo Box control

To make an element invisible in a List Box or Combo Box control, use gStoredValue.

Equivalence

The two following syntaxes are equivalent:

ListAdd(<Control name> [<Element>])

and

<Control name>[Index] = <Element>

Sorted/Unsorted List Box control

If the List Box control is sorted, the new element is inserted according to the sort order.
If the List Box control is not sorted, the new element is added at the end of the list.

The control type (sorted or not) is chosen during the control description ("Details" tab).

Use ListAdd rather than ListInsert to add an element to a sorted List Box control.

The element is added at the end of control, no matter whether the List Box control is sorted or not.

Customizing the elements found in a List Box or Combo Box control

To customize the elements in a List Box or Combo Box control (background color, image, design), use Graphic string functions.

Tabulations: Multi-element List Box control

To manage the tabulations in a List Box control (for aligning columns), use the TAB constant. For example:

ListAdd(LIST_Customer, LastName + TAB + FirstName)

In this example, all the first names start at the same position and are aligned one under the other.

Note The first call to the ListAdd function sets the tab position. These positions will be taken as reference for all values added thereafter. Similarly, if values have been typed entered in the editor, the positions of these values are taken as reference. During the first call to ListAdd, we advise you to define the width of columns with Complete. For example, to fix the width of columns found in "CUSTOMERS" to 10 characters:

ListAdd(LIST_Customer, Complete(LastName, 10) + TAB + Complete(FirstName, 10))

Adding an element to the browser

When adding an element in browser code, this element is added to the page displayed in the browser only. In order for this element to be added onto the server, ListAdd must be run on the server.

Calling ListAdd in browser code is useful when using AJAX technology, in "Programmed AJAX" mode (via AJAXExecute or AJAXExecuteAsynchronous).

Reminder In "automatic and immediate AJAX" mode, simply pass the server processing containing the function ListAdd FUNCTION in automatic AJAX mode. That's it! No additional programming is required. For more details, see AJAX.

Miscellaneous

To add elements into a Table control, use TableAdd.
ListAdd can be used on:
- a column of type "Combo Box" in a Table control.
- a "Table" Combo Box control.

Componente: wd300obj.dll

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Versión mínima requerida

Versión 9

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Última modificación: 27/03/2025

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