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Help / WLanguage / Managing databases / HFSQL / Binding functions
  • Binding between a control and a WLanguage variable or between a control and an item of a data file
  • Updating the items: Special cases
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Stored procedures
Automatically updates:
  • the values of a data file's items in memory with the values from the controls in the window. The data file items bound to the window controls are automatically updated with the values of these controls (even if they are grayed, inactive or invisible).
  • the value of the WLanguage variables with the value of the window controls. The WLanguage variables bound to the window controls are automatically updated with the values of these controls (even if they are grayed, inactive or invisible).
Remarks:
  • ScreenToFile cannot be used to write to the data file: the variables of the data file items can only be updated (i.e variables of the record loaded in memory). To modify the records, use HAdd, HModify, HWrite, etc.
  • WEBDEV - Server codePHP This function is also available for WEBDEV pages. It is equivalent to PageToFile.
  • PHP Only the binding to the items of a data file is supported. Bindings to WLanguage variables are not supported in this version.
Example
// Click the "Add" button
ScreenToFile()
HAdd(Customer)
IF HErrorDuplicates() = True THEN
Error("This number already exists")
END
Syntax
ScreenToFile([<Window> [, <Source>]])
<Window>: Window name
Name of the window that contains the controls. Summary: Called when a control gains focus.
PHP If this parameter is specified, it must correspond to the name of the current page. Otherwise, an error occurs.
<Source>: Optional character string
Name of the source containing the data to update. This source can be:
  • The name of a data file: only the controls bound to the items of the data file are taken into account.
  • The name of a WLanguage variable: only the controls bound to the WLanguage variable are taken into account.
    Remarks:
    • If the name of the variable is enclosed in quotes, the control will be bound to the specified variable.
    • If the name of the variable is not enclosed in quotes, the control will be bound to the variable data (e.g., a variable containing the name of another variable).
If this name is not specified, all the window or page controls that are bound to a data file described in the data model editor or to a WLanguage variable will be taken into account.
Remarks

Binding between a control and a WLanguage variable or between a control and an item of a data file

The binding between a control and a WLanguage variable or between a control and an item of a data file can be determined:
  • In the editor, in the control description window ("Binding" tab).
  • Programmatically, with the DataBinding property.

Updating the items: Special cases

  • To automatically assign the NULL value to an item with ScreenToFile:
    1. Check "NULL supported" for the item in the data model editor.
    2. Select the "NULL if empty" option in the Edit control bound to the item.
  • The items of the data file that are not bound to a control are not updated by ScreenToFile.
  • If multiple controls in the window are bound to the same data file item, ScreenToFile may not update the bound item properly. It is not recommended to bind multiple window controls to the same item.
  • ScreenToFile does not update the items with the values from Image controls. Use the HLinkMemo function.
  • ScreenToFile is not available on views.
  • Binding with "Secure Password" items: The value of the "Password" item cannot be modified until the user changes the value in the control bound to the item.
Component: wd290obj.dll
Minimum version required
  • Version 9
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Last update: 06/05/2023

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