List Editors in Multi-Column Mode
Multi-column mode is in effect only for editors that obtain their items from a data source.
You can use the Columns property to define and customize an editor’s column collection. Use the ASPxComboBox.Columns property for the ASPxComboBox editor, and the ASPxListBox.Columns property for the ASPxListBox editor. The Columns property allows you to get a collection of columns (ListBoxColumnCollection). Each item in the collection is an instance of the ListBoxColumn class.
Use the ListBoxColumn.FieldName property to bind each column editor to a data source field. You can also define a column’s header caption (WebColumnBase.Caption), width (WebColumnBase.Width), visibility state (WebColumnBase.Visible), unique identifier (WebColumnBase.Name) and tooltip text (WebColumnBase.ToolTip).
The ASPxComboBox control’s advanced features, such as incremental filter and item load on demand with callbacks, support multi-column mode. The editor’s edit box displays the selected item as a value with a format based on the ASPxAutoCompleteBoxBase.TextFormatString property’s setting.
When you use list editors in multi-column mode, item values are not saved to the ViewState. To reduce the frequency of page loads (when binding to data), you should use a cache (for example, in the Session).