This function retrieves a check box changed event from the event queue, which is triggered when the user clicks on the check box.
This function must be called to clear event 2 from guiWaitEvent.
Input:
None.
Output:
check_box : SYSHANDLE
The handle to the check box.
checked : BOOL
The new state of the check box
Returns: INT
0
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- Data is ready.
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-1
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- Interface is not open (see guiOpen).
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-6
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- Data is not ready
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-11
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- The GUI API is not supported.
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Declaration:
FUNCTION guiCheckBoxChangeEvent : INT;
VAR_INPUT
check_box : ACCESS SYSHANDLE;
checked : ACCESS BOOL;
END_VAR;
Example:
...
FUNCTION CheckBoxHandler
VAR
rc : INT;
handle : SYSHANDLE;
tag : DINT := 0;
checked : BOOL;
END_VAR;
rc := guiCheckBoxChangeEvent(check_box := handle, checked := checked);
IF rc = 0 THEN
guiGetTag(handle := handle, tag := tag);
IF checked THEN
DebugFmt(message:="Check box with tag \4 was checked", v4 := tag);
ELSE
DebugFmt(message:="Check box with tag \4 was unchecked", v4 := tag);
END_IF;
END_IF;
END_FUNCTION;
...
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