Die XdevListSelect ist eine Dropdown-Liste, aus der Anwender einen Wert auswählen können. Auch eine Mehrfachauswahl ist optional möglich. Die Dropdown-Liste enthält meistens die Werte einer Spalte einer Datenbanktabelle.
Die XdevListSelect ist eine Formular-Komponente und kann via XdevFieldGroup persistiert werden.
Wichtige 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.
MultiSelect - Allows multiple selections.
- 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.
Rows - Defines the height of a form component in rows. A row is roughly equal to the height of a character. This setting is only relevant if Toolbox> Height is set to ? (Undefined) or you are using an AbsoluteLayout.
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.
Wichtige Events:
valueChange - Is triggered after changes to the content, mainly by adding or deleting characters, however only if the UI component loses the focus.
Databinding:
- Daten-Container (Model)
XdevBeanItemContainer - Standard Daten-Container. Die Zuweisung erfolgt mit der Methode setContainerDataSource.
// Generates a new XdevBeanItemContainer 'productList' XdevBeanItemContainer<Product> productList = new XdevBeanItemContainer<Product>(Product.class); // Sets the XdevBeanItemContainer listSelect.setContainerDataSource(productList);
- XdevLazyEntityContainer - Wird ausschließlich von RapidClipse verwendet, wenn die Property Entity > Auto query data selektiert ist.
Examples:
Selektierung zurücksetzen - Setzt die Selektierung auf den Ausgangszustand. Dies löst ein valueChange Event aus.
listSelect.clear();
Fokus setzen - Weist dem XdevListSelect den Focus zu. Dies kann ggf. ein focus Event auslösen.
listSelect.focus();
Einträge hinzufügen - Weist dem XdevListSelect manuell Einträge hinzu.
listSelect.addItem("Eintrag 1"); listSelect.addItem("Eintrag 2");Direkte Zuweisung mehrerer Einträge.
listSelect.addItems("Eintrag 1", "Eintrag 2", "Eintrag 3", "Eintrag 4");Selektiertes Objekt - Liefert das selektierte Objekt zurück (Entity) - Beispiel mit Category Entity
BeanItem<Category> selectedItem = listSelect.getSelectedItem(); Category category = selectedItem.getBean();
oder
Category Category = (Category)listSelect.getValue();
oder - Liefert eine Liste aller selektierten Elemente
List<BeanItem<Category>> selectedItems = listSelect.getSelectedItems();
Elemente entfernen - Entfernt alle Elemente aus der XdevListSelect
listSelect.removeAllItems();
Element selektieren - Automatisches Selektieren eines Eintrages - Beispiel: erster Eintrag.
Collection<?> itemIds = listSelect.getItemIds(); listSelect.setValue(((List<Category>)itemIds).get(0));