ACTIVATE DATALIST

7.8.5,

The ACTIVATE DATALIST statement makes a DATALIST visible and allows the user to interact with it. An optional execution label may be provided to process information if the user selects the DATALIST. The instruction uses the following format:

Where:

label

Optional. A Program Execution Label.

datalist

Required. The name of a previously created DATALIST object variable or a pointer to a DATALIST object.

routine

Optional. A program execution label called when a mouse click occurs within the screen boundaries of the object.

result

Optional. A previously defined Numeric Variable in which the result code as described below is placed upon object selection.

Flags Affected: NONE

Note the following:

1. If the {routine} and {result} operands are not provided, the runtime performs a default action of setting the DATALIST to the selected item.

2. If the {result} operand is specified, it is passed a nine-digit number. The number indicates the item that was selected in the bottom eight digits or a zero when a single click occurs or a two when a double click occurs.

3. If the {result} operand is too small to contain the value, the OVER flag is set upon entry to the {routine}. This flag setting does not occur at the time of the ACTIVATE butat the time the {routine} is called.

4. The {routine} is called as if a CALL instruction was performed. It is only called when an EVENTCHECK or EVENTWAIT is executed.

5. The {routine} is called when an item is selected in the DATALIST.

6. When an operator performs a double click action, the {routine} is called once for each click. The ninth digit of the {result} operand distinguishes between the clicking actions.

7. When the {routine} is complete, a RETURN instruction continues execution at the instruction following the EVENTWAIT or EVENTCHECK. Otherwise, a NORETURN instruction should be executed to clear the return address from the call stack.

8. All other object operations, such as scroll bar manipulation and screen updating, are automatically performed by the runtime.

9. If the DATALIST specified by an ACTIVATE instruction is already active, the old {routine} and {result} operands are replaced with the new {routine} and {result} operands.

10. An object must be CREATEd before it is activated. If this is not done, a runtime error of O105 is generated.

11. If insufficient memory is available to perform the operation, a runtime error O106 is generated.

12. If a FILEPI instruction is active, it is terminated.

See Also: Example Code, ACTIVATE, DEACTIVATE, Object Output Instructions