WtList Function

Controls the characteristics of scrolling list widgets.

Note:

Making piecemeal changes to large lists requires multiple memory allocations and can result in repeated redraws of the list contents as each change is made. To avoid this, write your code so changes are made in bulk using one of the following methods:

WwSetValue: this method always uses bulk changes.

WtList: delete the entire list with the 'DeleteAll' function and update with the 'Add' function

WwListUtils: delete the entire list using the Delete keyword in conjunction with the All keyword and then update the list using the Add keyword.

In general it is much more efficient to delete and replace the entire list in two operations than it is to iteratively remove or replace many individual items in an existing list.

Usage

status = WtList(function, widget[, parameters])

Parameters

function:

'Add' — Add specified item(s) to the list.

'Delete' — Delete specified item(s) from the list.

'DeleteAll' — Delete all items from the list.

'Deselect' — Deselect specified item(s) in the list.

'DeselectAll' — Deselect all items in the list.

'ItemCount' — Number of items in the list.

'Items' — Get items in the list.

'Select' — Select specified item(s) from the list.

'SelectAll' — Select all items from the list.

'SelectedCount' — Number of selected items.

'Selected' — Get selected items.

'Replace' — Replace specified item(s) in the list.

widget — The list widget ID.

parameters:

For 'Add' — (p₁) A string or array of strings; (p₂) a long integer representing the position at which to add the item. The default is the end position.

For 'Delete' — (p₁) A string or array of strings.

For 'Deselect' — (p₁) A string or array of strings.

For 'ItemCount' — (p₁) Number of items in the list (long, output).

For 'Items' — (p₁) Items in the list. Array of strings (output).

For 'Menu' — (p₁) Menu shell ID (long).

For 'Select' — (p₁) A string or array of strings.

For 'SelectedCount' — (p₁) Number of selected items (long, output).

For 'Selected' — (p₁) Selected items. Array of strings (output).

For 'Replace' — (p₁) A string or array of strings; (p₂) position of first items to be replaced.

Keywords

Notify — If specified, a callback is called during Select or Deselect operations.

Discussion

The list utility lets users choose an action from a list of actions. For detailed information on the list utility, see the description of XmList in the OSF/Motif Programmer’s Reference.