- Vytvoril/a D2000 Dev Team, naposledy zmenil/a D2000 Doc Team dňa sep 29, 2021
ON CHANGE action
ON CHANGE objIdent GOTO ProcName [NONE]
| objtIdent | in | Value identifier (or a group of values). |
| ProcName | in | Procedure name (it must meet the rules for object name). |
A group of values can represent a row, a column or entire object of Structured variable type.
For example:
- the identifier of the second row: SV.Structure[2] (column name is not stated)
- the identifier of the column Int: SV.Structure[0]^Int (the row index is 0)
- the identifier of all values (entire structure): SV.Structure, or SV.Structure[0] (the row index is 0).
The traced value can be identified through HOBJ or VOBJ.
For example:
INT _hbj ... ON CHANGE (_hbj) GOTO ValueChanged
After the action execution, for example:
ON CHANGE Sec GOTO ValueChanged
The procedure ValueChanged is to be called always, when a value change of the object Sec occurs (therefore every second). If the following action is performed within the frame of the script:
ON CHANGE Sec GOTO ValueChanged NONE
calling the procedure ValueChanged is to be terminated during a value change of the object Sec. At the action notation, it is able to state the structure item:
ON CHANGE SV.Structure[2]^Int GOTO ValueChanged
ON CHANGE Sec GOTO ValueChanged
ON CHANGE Sec GOTO ValueChanged1
In this case, the procedures ValueChanged and ValueChanged1 are to be called during a change of the object Sec.
A procedure called on the basis of a value change must be declared in the following way:
PROCEDURE ProcName(ValueType value, ALIAS _referenceToObject, INT _row, INT _column)
Where:
ProcName is the procedure name, that meets the rules for procedure name.
_value is a parameter, to which a new value of the monitored object (or an item during the monitoring of a structure item change).
ValueType determines the type of the parameter _value. If the type is not selected correctly (in regard to a value changed), an invalid value is to be assigned to the parameter.
_referenceToObject is a parameter of ALIAS type. After the procedure start, it is initialized to refer to the object, which changes the value (in case of monitoring an item, ALIAS is referred to the whole structure, not the item).
_row, _column are the parameters of INT type. They make a difference only if the procedure is called by reasons of a value change of a structured variable item. Otherwise they are set to the value of 0. In case of a value change, the parameter _row contains the serial row number and the parameter _column contains the serial column number within the frame of the particular structured variable.
The action is usable only within the frame of the script of an Active picture or an object of Event type with the active option Server Event.
- the object Sec
- the item SV.Structure^Int
- any item in the row Int (SV.Struktura[0]^Int)
to an operator on the desktop of the D2000 HI process.
; Handling changes of values
PROCEDURE ValueChanged(REAL _value, ALIAS _obj, INT _row, INT _col)
; Is a value of the object Sec changed ?
IF _obj\HBJ = Sec\HBJ THEN
MESSAGE "The object Sec changed = " + %IToStr(_value) ON _FROM_HIP
; Is a value of the object SV.Structure changed ?
ELSIF _obj\HBJ = SV.Structure\HBJ THEN
IF _row = 1 & _col = 1 THEN
MESSAGE "The item SV.Structure^Int changed = " + %IToStr(_value) ON _FROM_HIP
ELSE
MESSAGE "In the column SV.Struktura[0]^Int, change of the row = " + %IToStr(_row) ON _FROM_HIP
ENDIF
ENDIF
END ValueChanged
; Initialization part
BEGIN
ON CHANGE Sec GOTO ValueChanged
ON CHANGE SV.Struktura^Int GOTO ValueChanged
ON CHANGE SV.Struktura[0]^Int GOTO ValueChanged
END
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