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Value list provider

Dependent selection lists in combo boxes – e.g. only the contacts of the selected customer.

HOW-TO APPLICATION DEVELOPER STAND: JUL 2026 GILT FUER NUCLOS 4.2026.X

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What is a value list provider?

A value list provider (VLP) dynamically restricts the choices in a combo box / list of values – depending on another selected value. Typical cases: show only the contacts of a selected customer, or only the rooms of a selected building.

Example: contacts per customer.

Step 1: create the data source

Menu: Administration → Data sources → Valuelist Provider. Define a parameter (e.g. intid_kunde) that passes the internal ID of the triggering record.

Handy

If the parameter is named intid, Nuclos automatically uses the INTID of the main record.

The value list provider data source.

Step 2: add the VLP to the layout

In the layout editor attach the value list provider to the target field (here: contact) via the palette. An optional default flag lets you preselect a standard value (e.g. the default address).

Value list provider in the layout.

Step 3: create the layout rule

On the source field (here customer) define a layout rule:

Field	Value
Event	When the value changes
Action type	Update value list
Business object	BO of the target component (only for sub-forms; otherwise empty)
Target component	Combo box whose values are updated
Parameter	Parameter name from the data source

Layout rule „update value list“.

Predefined value list providers

Status: restricts the status field's value list to certain business objects (parameter business objects = internal BO name).
Process: restricts the action field's value list (only on the NuclosProcess field).
Parameters: provides value lists in column definitions of sub-form data (parameter showValue).

System parameters

System parameters in condition/SQL: $username, $mandator, $locale, $searchmode (in single quotes). They must be declared in the VLP under parameters first.

VLP for text attributes

To offer a fixed value list for a text attribute (without a reference, e.g. for „salutation“), choose a combo box in the layout editor with show all attributes ticked, attach a VLP (leave the ID field empty). With value list editable users may also enter their own values.