XdevComboBox

The XdevComboBox is a combination of an input field, a button, and a drop-down list, from which the user can select a value. The drop-down list predominantly contains the values contained in a given column in the database table.

The input field of an XdevComboBox is editable by default. The drop-down list entries are automatically re-filtered in accordance with each input. The selected entry is displayed in the XdevComboBox. The XdevComboBox is a form component and can be persisted via the XdevFieldGroup.

Important properties:

• Auto query data - Automatically performs a database query and fills the entity connected to the UI component. Data that can’t be displayed will be lazily loaded (lazy-loading). The XdevLazyEntityContainer will be used as Data Container.

• Connected form - Connects the UI component (master) to the specified XdevFieldGroup (detail). 

• Entity -  Connects the assigned entity to the UI component.

  • Properties - Shows the attributes of the connected entity, specified here, in the UI component e.g. {%company}. You can also display multiple attributes, such as {%company}, {%carmodels}, {%price}. Thus, the potential settings made in the Entity Editor will be overwritten in Settings > Entity caption as well as in Properties > ItemCaptionValue.
  • Data - Instead of the default search strategy of Auto query data, it uses the query method findAll or a custom query method. findAll  transmits the entire query result and uses the  XdevBeanItemContainer as a data container. Lazy loading is not supported.
  • Hierarchy - Only for XdevTree.

• ItemCaptionFromAnnotation - Displays attributes of the connected entity in the UI component. These attributes were globally defined in the Entity Editor in Settings > Entity caption, e.g. {%company}, {%carmodels}, {%price}.

• ItemCaptionValue - Shows the attributes for the connected entity, specified here, in the UI component e.g. {%company}. You can also display multiple attributes, such as {%company}, {%carmodels}, {%price}.  Thus, any potentially set global setting in the Entity Editor will be overwritten in Settings > Entity caption. 

• Master component - Master component connected to the UI.

• PageLength - Displays the specified number of entries.

• ReadOnly 

• Required - The form component is defined as a mandatory field. You need to make a selection from the available options, complete the field, or select the required option.

• RequiredError - An error message that appears when a form component that is defined as a mandatory field is not filled out, selected or no selection has been made.

• ScrollToSelectedItem - When a drop-down list is activated, the system automatically scrolls to the value set in the XdevComboBox.

• TabIndex - Defines the sequence in the tab index. The tab index defines the order of several UI components. These can be selected one by one by pressing the Tab key.

• TextInputAllowed - Allows you to enter values. With each new entry, the drop-down list is automatically re-filtered.

  • FilteringMode - filtering option.
    • null - errors
    • OFF - Does not filter the drop-down list.
    • STARTSWITH - Default setting. Displays all entries that begin with the search term.
    • CONTAINS - Displays all entries that contain the search term.

Important events:

• valueChange - Is triggered after changes to the content, mainly by adding or deleting characters, however only if the UI component loses the focus.

Data binding:

• Data container (model)

  • XdevBeanItemContainer - Standard data container. The allocation is set using the setContainerDataSource method.

    // Generates a new XdevBeanItemContainer 'productList'
    XdevBeanItemContainer<Product> productList = new XdevBeanItemContainer<Product>(Product.class);
     
    // Sets the XdevBeanItemContainer
    comboBox.setContainerDataSource(productList);

  • XdevLazyEntityContainer - RapidClipse exclusively uses this when the property Entity > Auto query data is selected.

Examples:

• Add entries - Manually add entries to the XdevComboBox.

  comboBox.addItem("Eintrag 1");
  comboBox.addItem("Eintrag 2");

  Direct allocation of multiple entries.

  listSelect.addItems("Eintrag 1", "Eintrag 2", "Eintrag 3", "Eintrag 4");

• Selected object - Returns the selected object (entity) - Example: category entity.

  Category Category = comboBox.getSelectedItem();

  or

  Category Category = (Category)comboBox.getValue();

• Remove elements - Removes all the elements from the XdevComboBox.

  comboBox.removeAllItems();

• Select element - Automatic selection of an entry - Example: first entry.

  Collection<?> itemIds = comboBox.getItemIds();
  comboBox.setValue(((List<Category>)itemIds).get(0));

• Reset selection - Sets the selection to the initial state. This triggers a valueChange event.

  comboBox.clear();

• Read random value of the selected object - Example: "Category name"

  String categoryName = comboBox.getSelectedItem().getBean().getCategoryname();

• Read XdevComboBox data - Generates a new XdevBeanContainer productContainer of Product category and assigns this with the getContainerDataSource method to XdevBeanContainer of the XdevComboBox.

  XdevBeanContainer<Product> productContainer = comboBox.getContainerDataSource();

All XdevComboBox Methods 

Note:

• XdevComboBox > Properties > FilteringMode > null leads to error.