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Studio Developer Manual / Version 2310

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5.3.5 Model Beans for Custom Components

When creating complex GUI components, it is good practice to provide an abstract model in the form of a bean to back the view. In combination with ValueExpressions this allows an easy dependency tracking between the different widgets of a complex GUI. The best practice here, is to lazy initialize the model bean through a getter method. The bean itself is created there using the call beanFactory.createLocalBean() upon first access:

import Config from "@jangaroo/runtime/Config";
import Panel from "@jangaroo/ext-ts/panel/Panel";
import Bean from "@coremedia/studio-client.client-core/data/Bean";
import beanFactory from "@coremedia/studio-client.client-core/data/beanFactory";

class MyComponent extends Panel {
  #model: Bean;

  constructor(config: Config<MyComponent>) {

  getModel(): Bean {
    if (!this.#model) {
      this.#model = beanFactory._.createLocalBean();
    return this.#model;

  #initModel(config: Config<Panel>): void {
    this.getModel().set("myProperty", config.title);


export default MyComponent;

Example 5.20. Model bean factory method

The model can then be used inside a ValueExpression and be bound to components:

import Config from "@jangaroo/runtime/Config";
import TextField from "@jangaroo/ext-ts/form/field/Text";
import BindPropertyPlugin from "@coremedia/studio-client.ext.ui-components/plugins/BindPropertyPlugin";
import ValueExpressionFactory from "@coremedia/studio-client.client-core/data/ValueExpressionFactory";

// inside items of some container:
Config(TextField, {
  itemId: "...",
  plugins: [
    Config(BindPropertyPlugin, {
      bindTo: ValueExpressionFactory.create("myProperty", this.getModel()),
      bidirectional: true,

Example 5.21. Model bean access

Here a text field is configured to display the value of a property, but of course arbitrary widgets can be used.

In fact, the property is not directly accessed by the plugin, but indirectly through a value expression that, in this case, simply evaluates to a property value. Value expressions will be discussed in the next section.

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