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- Overview
- Initializing a List Box control
- Initializing an element
- Populating a List Box control
- Selecting an element in a List Box control
- Selecting a row
- Setting the position on the last element
- Retrieving the element selected in a List Box control
- Retrieving the index of the selected element
- Getting the value of the selected element
- Iterating over the elements of a List Box control
- Properties specific to List Box controls
Handling List Box controls programmatically (prefix syntax)
WINDEV, WEBDEV and WINDEV Mobile allow you to programmatically handle List Box controls. To do so, use the variable of the List Box control in the code. This variable is of type numeric. The variable of the List Box control: - corresponds to the name of the List Box control.
- is initialized with the index of the element selected in the control.
To handle an element of the List Box control, use the following notation: <List Box control> [<Element index>] Initializing a List Box control Initializing an element Remark: To modify an element in a List Box control, use the following syntax: <List Box control>[Index] = <Value> For example:
// Add elements LIST_LIST1.Add("MOORE") LIST_LIST1.Add(Cust_Name) // Modify elements LIST_LIST1[3] = "MOORE"
Populating a List Box control To initialize a List Box control, simply use an iteration loop to initialize all the elements in the control.
Index is int FOR Index = <Start position> TO <End position> <List Box control>.Add(<Value>) END Example:
i is int FOR i = 1 TO 52 LIST_LIST1.Add(NAME[i]) END
Selecting an element in a List Box control Selecting a row To select the element at row <Index>, use: - the direct assignment:
<List Box control> = Index - the <List Box>.SelectPlus function:
<List Box control>.SelectPlus(<Index>)
Setting the position on the last element To set the position on the last element of the List Box control, use: Retrieving the element selected in a List Box control Retrieving the index of the selected element To retrieve the index of the selected element, use one of the following syntaxes: - directly read the element:
Index = <List Box control> - the <List Box>.Select function:
Index = <List Box control>.Select()
Remark: For multi-selection List Box controls, <List Box>.Select is used to retrieve the selected elements. // Retrieve the elements of a multi-selection List Box control Rank is int = 0 Â // selection number Index is int = 0 Â // index of the selected element LOOP Rank = Rank + 1 Index = LIST_LIST1.Select(Rank) IF Index = - 1 THEN BREAK END
Getting the value of the selected element To retrieve the value of selected element, use one of the following syntaxes: - Syntax 1:
Index is int = <List Box control> <Variable> = <List Box control>[Index] - Syntax 2:
<Variable> = <List Box control>[<List Box control>] - Syntax 3: DisplayedValue property (in server code only)
Variable> = <List Box control>[Index].DisplayedValue
Caution: The stored value can be different from the displayed value. To get the stored value corresponding to one of the rows in the List Box control, use the StoredValue property. Iterating over the elements of a List Box control The FOR EACH statement performs different types of iterations on List Box controls: - Iterating over the elements in the control. The following syntax is used:
FOR EACH ROW [<Index> [, <Counter>]] OF <List Box control> ... END where: - <Index>: Optional Integer variable. For each iteration, contains the index of the current row.
- <Counter>: Optional Integer variable. This variable counts the number of iterations.
- Iterate over the selected elements. The following syntax is used:
FOR EACH SELECTED ROW [<Index>, [<Counter>]] OF <List Box control> ... END where: - <Index>: Integer variable. For each iteration, contains the index of the current selected row.
- <Counter>: Optional Integer variable. This variable counts the number of iterations (number of selected rows for example).
Properties specific to List Box controls The following properties are specific to List Box controls: | | All types of List Box controls | HorizontalAlignment | Gets and sets the horizontal alignment of the elements in the List Box control. | LineHeight | Gets and sets the height of the rows in a List Box control. | Memory | Indicates if the specified List Box control is populated programmatically or is based on a data file. | Count | Gets the number of rows in a List Box control. | FillType | Indicates how a control is populated (programmatically, from a data file or from a variable). Applies to Table, List Box, ListView, Combo Box and Looper controls. | DisplayedValue | Gets the value of the current row or the value of a specific row in the List Box control. | StoredValue | Gets the value currently stored when selecting a row in the List Box control. | Empty | Indicates if a List Box control is empty. | List Box control populated programmatically only | InitialContent | Gets the initial content of a List Box control populated programmatically. | Sorted | Indicates if a List Box control populated programmatically is sorted, or sorts the control. | List Box control based on a data file only | BrowsedFile | Gets or sets the data file or query used to display records in List Box controls. | AutoBrowse | Indicates if a List Box control is looped through automatically or programmatically. | DisplayedItem | Gets and sets the item displayed in a List Box control. | StoredItem | Gets and sets the stored item of a List Box control. | BrowsedItem | Gets and sets the item used to automatically loop through List Box controls. |
For a complete list of WLanguage properties that can be used with a List Box control, see Properties associated with List Box controls.
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