Context Parameter

This page is for application designers who need to configure functionality in table-actions. It explains how to set context parameters.

Overview

When a user triggers a record-action, table-action, PhixFlow can take into account other values or attributes to decide whether or not to run. These are called context parameters. At the start of a table-action, PhixFlow calculates the context parameters first. This is because they are needed to decide whether or not to run the table-action. This is called action validation.

Use context parameters to identify values:

  • to pass from one screen to another
  • for action validation
  • that determine record-actions
  • to determine what your action will do.
    Examples include:
    • which screen will open after the action completion
    • which updates will take place (using record-action rules)
    • whether or not a task plan will run.

The order of the context parameters is important!

Context parameter values can come from:

  • a field in a form
  • a calculation.
    The source values for the calculation can be
    • a field in a form
    • previous context parameters
  • results obtained from lookups.

You cannot directly refer to a context parameter from another context parameter. However, you can refer to a dollar $-variable that is defined in another context parameter expression. Make sure the dollar variable will be calculated before the current context parameter expression is evaluated. This can be useful to avoid repeating the same calculation. For example, sometimes you need to use a value in both a record-action and screen-rule. 

In the table-action properties → Context Parameters section, the Include Previous Context Parameters adds to the context parameters of your table-action any existing context parameters from the screen. You can overwrite them by including it in your table-action and giving it a new value.

For information about setting a global $-variable using a context parameter, see Using $-variables Throughout an Application.

This properties tab is not available from the repository. It opens from an Table-Action properties → Context Parameters section.

Property Pane Toolbar

For information about the toolbar options, see the Common Properties page, Toolbars and Controls section.

 Properties Tab

Parent Details

If this item is within or belongs to another, its parent name is shown here. See the Parent Details section on the Common Properties page for more details.

Basic Settings

FieldDescription
OrderEnter the order in which context parameters will be evaluated.
NameEnter the name of the context parameter.
Either select an attribute name from the drop-down list, or enter a different name.

Use these values as

Select an option to set these values as:

  • Default Values: the context parameter has a default value, which can be changed.
  • Fixed Values: once set the value cannot be changed.
Expression

Enter the expression for the context parameter. 

Unlike table-action attribute expressions, context parameter expressions can evaluate to a list of values as well as single values.

The context parameter expressions can refer to:

  • data from the screen, form or view from which the table-action was initiated
  • $-variables used in other context parameter expressions on the same table-action.

Use the notation:

  •  to refer to values on a form:
       _prompt.<Form Field Name>   
  • to refer to attributes of selected records:
       <View name or alias>.<Attribute name or alias>   

The expression can include the message functions debug, info, warning, and error, which write messages  to the system console logs. Remember that the error function stops the table-action from completing.

 Audit Tab

Audit Summary

See the Common Properties page, Audit Summary section.

Example Context Parameter

A view called Customers shows a list of customers including the account ID, name and other account details. You want to create a button to open up another screen, containing a view called Invoices, which will show the invoices for the customer selected on the Customers view. To do this:

  1. Add an action button to the Customers view, and configure it to open the screen containing the Invoices view.
  2. Add a context parameter called Account to the table-action, with the context parameter expression set to customers.account_id.
  3. On the background filter of the Invoices view, set the filter to only select those invoices whose account_id is equal to _context.account.

Referring to a Context Parameter

The values returned by the context parameter expressions can be referenced by:

  • the validation expression
  • the filter
  • the maximum and minimum items expressions
  • any table-action attribute expressions
  • any screen opened by this table-action.

The context values are referenced using the syntax:

_context.<context parameter name>

Sections on this page

Learn More

For links to all pages in this topic, see Using Table-Actions.


Terminology changes in progress

As part of the redesign of PhixFlow, we are changing the following terms:

dashboard → screen   
stream → table
stream attributes → attributes
stream item → record
stream set → recordset
stream view → view
stream item action → record-action 
stream action → table-action
driver class → database driver