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4D v19
VP Run offscreen area
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VP Run offscreen area ( parameters ) -> Function result | ||||||||
Parameter | Type | Description | ||||||
parameters | Object |
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Object containing the offscreen area's attributes | |||||
Function result | Mixed |
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.result property of the onEvent object, or Null if does not return a value | |||||
The VP Run offscreen area command creates an offscreen area in memory which can be used to process 4D View Pro area commands and functions.
In parameters object, pass any of the following optional properties. These properties will be available through the This command within the onEvent method and reference the instance:
Property | Type | Description |
area | text | The name of the offscreen area. If omitted or null, a generic name is assigned (e.g., OffscreenArea1). |
onEvent | object (formula) | A callback method that will be launched when the offscreen area is ready. It can be either:
The callback method can be used to access the 4D View Pro object. See 4D View Pro form object variable. |
autoQuit | boolean | True (default value) if the command must stop the formula execution when the On End URL Loading or On URL Loading Error events occur. If false, you must use the CANCEL or ACCEPT commands in the onEvent callback method. |
timeout | real | Maximum time (expressed in seconds) before the area automatically closes if no event is generated. If set to 0, no limitation is applied. Default value: 60 |
result | mixed | Result of the processing (if any) |
<customProperty> | mixed | Any custom attribute to be available in the onEvent callback method. |
The following property is automatically added by the command if necessary:
Property | Type | Description |
timeoutReached | boolean | Added with true value if timeout has been exceeded |
Note: The offscreen area is only available during the execution of the VP Run offscreen area command. It will automatically be destroyed once execution has ended.
The following commands can be used in the callback method:
You want to create an offscreen 4D View Pro area and get the value of a cell:
// OffscreenArea class declaration
Class constructor
C_TEXT($1)
This.filePath:=$1
// This function will be called on each event of the offscreen area
Function onEvent
Case of
:(FORM Event.code=On VP Ready)
VP IMPORT DOCUMENT(This.area;This.filePath)
This.result:=VP Get value(VP Cell(This.area;6;22))
ALERT("The G23 cell contains the value: "+String(This.result))
End case
the OffscreenArea callback method:
$o:=cs.OffscreenArea.new()
$result:=VP Run offscreen area($o)
You want to load a large document offscreen, wait for all calculations to complete evaluating, and export it as a PDF:
//OffscreenArea class declaration
class constructor($pdfPath Text)
This.pdfPath:=$pdfPath
This.autoQuit:=False
This.isWaiting:=False
Function onEvent
Case of
:(FORM Event.code=On VP Ready)
// Document import
VP IMPORT DOCUMENT(This.area;$largeDocument4VP)
This.isWaiting:=True
// Start a timer to verify if all calculations are finished.
// If during this period the "On VP Range Changed" is thrown, the timer will be restarted
// The time must be defined according to the computer configuration.
SET TIMER(60)
:(FORM Event.code=On VP Range Changed)
// End of calculation detected. Restarts the timer
If(This.isWaiting)
SET TIMER(60)
End if
:(FORM Event.code=On Timer)
// To be sure to not restart the timer if you call others 4D View command after this point
This.isWaiting:=False
// Stop the timer
SET TIMER(0)
// Start the PDF export
VP EXPORT DOCUMENT(This.area;This.pdfPath;New object("formula";Formula(ACCEPT)))
:(FORM Event.code=On URL Loading Error)
CANCEL
End case
the OffscreenArea callback method:
$o:=cs.OffscreenArea.new()
$result:=VP Run offscreen area($o)
Product: 4D
Theme: 4D View Pro Language
Number:
905271
Created: 4D v18 R4
4D View Pro Reference ( 4D v19)