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Help / WLanguage / Managing databases / HFSQL / Binding functions
  • Binding between a control and a WLanguage variable or between a control and a data file item
  • Section updates: 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:
  • The ScreenToFile function cannot be used to write to the data file: only the variables of the data file fields are assigned (i.e. the variables of the record loaded into memory).. To modify the records, use HAdd, HModify, HWrite, etc.
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.
<Source>: Optional character string
Name of the source containing the data to update. This source can be:
  • The name of a data file: only fields linked to this data file are taken into account.
  • The name of a WLanguage variable: only fields linked to this 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 a data file item

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

Section updates: Special cases

  • To automatically assign the NULL value to an item with ScreenToFile:
    1. Check "Support NULL values" in the data file description.
    2. Check "Allow NULL values" for the item in the data model editor.
    3. Check "Return NULL if empty" in the "Details" tab of 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 or page are bound to the same data file item, ScreenToFile may not update the bound item properly. It is not recommended to bind multiple controls of a window or page 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.
  • Link with "Secure password" fields : The value of the "Secure password" field is not modified until the user modifies the value in the field linked to the field.
Business / UI classification: UI Code
Component: wd300obj.dll
Minimum version required
  • Version 9
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Last update: 10/02/2024

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