Combo Box
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The BootstrapComboBox editor combines the functionality of a single-line text editor, button editor, and dropdown list editor. The editor’s dropdown displays a list of items that can be selected by end-users.
Bootstrap Combo Box offers the following features.
Data-Bound and Unbound Modes Support
Editor content can be generated dynamically by binding the editor to a data source, as well as manually populating the control’s item collection. When retrieving items from the data source, item characteristics such as the text, value, and image are obtained from specific data fields. These data fields can be either defined manually using an item’s FieldName property or are obtained automatically, provided that the data fields in the data source are named like the item’s characteristics (Text, ImageURL, Value).
Three Item Loading Modes
The Bootstrap Combo Box control supports three item loading modes.
Loading Mode Description Affected Properties Default All items are loaded to the client side, so all data operations (such as scrolling, filtering) are performed on the client, without generating a round trip to the server. EnableCallbackMode=”False” On-Demand Items are loaded from the server on demand using callbacks. For instance, list items that are not currently displayed within the editor’s dropdown window can be dynamically loaded when an end-user scrolls the list. This callback mode forces the first page load much faster, since only a few items need to be initially loaded. EnableCallbackMode = “True” Dynamic You can manually populate a dropdown list with the required item portions, based on the currently applied filter criteria (the ASPxAutoCompleteBoxBase.IncrementalFilteringMode property value is other then “None”) and the list scrolling performed. EnableCallbackMode=”True” See also: Item Load Modes
Incremental Filtering
You can enable your end-users to filter list items dynamically, based upon the text typed into the editor’s input box on the client side (find-as-you-type filtering). The following filter modes are available.
Loading Mode Description StartsWith The editor is filtered for list items that begin with the search string. Contains The editor is filtered for list items that contain the search string. The found search string is highlighted within items for clarity. You can enable the required filter mode using the ASPxAutoCompleteBoxBase.IncrementalFilteringMode property.
Delayed Filtering
You can define the time interval between the time a user starts typing within the editor’s edit box (the ASPxAutoCompleteBoxBase.IncrementalFilteringDelay property) and the time filtering is applied. Moreover, when the Bootstrap Combo Box editor is in incremental filtering mode, it has the capability to start filtering only after an end-user has typed a specific number of symbols in the editor’s text box (see the ASPxAutoCompleteBoxBase.FilterMinLength property).
Display Formatting
Editor display values can be formatted using the standard formatting mechanism. The ASPxAutoCompleteBoxBase.TextFormatString property allows you to define the pattern used to format the selected item’s text displayed within the editor’s edit box.
Item Images
You can define images for individual items (see the BootstrapListEditItem.IconCssClass property). Images associated with list items are displayed within the editor’s dropdown list. The selected item image can be displayed within the editor’s edit box in addition to the text.
Item Template
The Bootstrap Combo Box control provides the ASPxAutoCompleteBoxBase.ItemTemplate to create a custom layout for its items.
Customizable Button Collection
The Bootstrap Combo Box control provides a collection to maintain its custom edit buttons. Each button exposes a set of properties allowing the button’s appearance and behavior to be defined. The settings of the default button, which invokes the dropdown window when clicked, can be customized as well.
Built-in Validation
The Bootstrap Combo Box control allows you to perform data validation both on the client and server side.
Full-Featured Client-Side API
Bootstrap Combo Box provides you with a comprehensive client-side API. This API is implemented using JavaScript and is exposed using the BootstrapClientComboBox object. The BootstrapClientComboBox object serves as a client-side equivalent of the BootstrapComboBox control.
You can modify the editor behavior using the following methods.
Method Description ASPxClientComboBox.AddItem Adds a new item to the end of the control’s item collection. ASPxClientComboBox.BeginUpdate Prevents the client combobox editor from being rendered until the ASPxClientComboBox.EndUpdate method is called. ASPxClientComboBox.ClearItems Removes all items from the client combo box editor. ASPxClientComboBox.EndUpdate Re-enables editor render operations after a call to the ASPxClientComboBox.BeginUpdate method and forces an immediate re-rendering. ASPxClientComboBox.FindItemByText Returns a combo box item by its text. ASPxClientComboBox.FindItemByValue Returns a combo box item by its value. ASPxClientComboBox.GetItem Returns an item specified by its index within the combo box editor’s item collection. ASPxClientComboBox.GetItemCount Gets the number of items contained in the editor’s item collection. ASPxClientComboBox.GetSelectedIndex Returns the index of the selected item within the combo box editor. ASPxClientComboBox.GetSelectedItem Returns the combo box editor’s selected item. ASPxClientComboBox.GetText Gets the text displayed in the editor’s edit box. ASPxClientComboBox.InsertItem Adds a new item to the control’s items collection at the specified index. ASPxClientComboBox.MakeItemVisible Scrolls the editor’s item list, so that the specified item becomes visible. ASPxClientComboBox.PerformCallback Sends a callback to the server. ASPxClientComboBox.RemoveItem Removes an item specified by its index from the client list editor. ASPxClientComboBox.SetSelectedIndex Sets the combobox editor’s selected item specified by its index. ASPxClientComboBox.SetSelectedItem Sets the list editor’s selected item. ASPxClientComboBox.SetText Specifies the text displayed within the editor’s edit box.