Tree List

• Nov 27, 2020
• 7 minutes to read

The DevExpress WinForms Tree List is a hybrid control that allows you to display data as a tree, a grid, or a combination of both, regardless of data complexity.

The Tree List can be used in either bound or unbound mode, with full support for data editing and validation. Since it includes grid functionality, you can also sort, filter and search for data, as well as calculate summaries using aggregate functions. Like other DevExpress WinForms controls, the Tree List fully supports DevExpress skins, so that you can customize the appearance of your application.

Refer to the following links for detailed info.

Learn the Basics

This section includes articles that cover essential Tree List control terms and techniques.

• Main Features
  Enumerates all Tree List capabilities in a compact list format.

• Visual Elements
  Demonstrates all UI elements provided by the Tree List control.

Nodes

The Tree List control displays records of the associated data source by means of nodes. Nodes, however, can be much more complex than a number of cells displaying dataset field values. The documents in this section describe the term “node”, and provide information on how to perform operations on nodes. Nodes An overview topic that explains what Tree List nodes are. Using the Nodes Iterator Nodes iterator is an object that allows you to traverse Tree List nodes without writing recursive code manually. Custom Nodes This topic shows how to create custom nodes and use them in your Tree List control.

Columns

The Tree List control displays data by means of nodes and columns. Nodes correspond to individual records, while columns represent data source fields. This section contains description for columns themselves and elements related to the column layout - bands and preview sections. Columns The title columns article. Contains the detailed info on columns, their layout, behavior and appearance settings. Bands Bands are visual and logical groups into which you can arrange columns. You can hide, display and reorder bands along with their child columns. This document describes the band features, how to anchor bands and how to organize them into a hierarchical structure. Preview Sections Preview sections are regions below Tree List records, stretched across the entire node width. These regions are non-editable and designed to display large memo fields or custom data for a given record. TreeView Style You can activate this visual style to imitate the appearance of the standard TreeView control. The TreeView style is supported in single-column and multi-column modes.

Data Binding

This section contains all required info related to binding the Tree List control to various data types, as well as operating in unbound mode. Data Binding Common Concepts In this section you will find general information on data binding concepts, shared among all DevExpess data-aware controls. Tree Generation Algorithm in the Tree List Learn how the Tree List generates its node hierarchy and what requirements the control provides for the data source. Virtual Mode (Dynamic Data Loading) Using Events (Tree List Level) Explains how to load data into a Tree List dynamically using only events (virtual mode). Virtual Mode - Binding to a Hierarchical Business Object (Data Source Level) This topic is dedicated to a particular case of virtual mode where the Tree List is bound to an instance of a custom class. Unbound Mode The overview article dedicated to the Tree List Unbound Mode. Unbound Columns This page covers unbound columns, which help you display custom data within the Tree List control. These columns are not bound to fields in the data source, and data for these columns needs to be provided using expressions or a dedicated event.

Data Editing

Articles in this section demonstrate different data editing approaches supported by the Tree List control. Inplace Editors Learn how to embed DevExpress editors into your Tree List data cells. Obtaining and Setting Cell Values Explains how to get and set cell values. Assigning Editors to Columns Illustrates how to implement the most typical scenario where cells that belong to the same column use the same in-place editors. Assigning Editors to Individual Cells This topic illustrates how to assign different editors to different cells in the same column. Showing and Hiding Editors Learn how to ‘teach’ your Tree List to respond to activating and closing in-place editors. The topic also provides info on displaying and closing cell editors manually.

Sorting

Topics in this section provide information about sorting Tree List data against specific columns. TreeList Sorting Specifics Contains technical info related to sorting. Sorting at Runtime Illustrates how end-users can sort data at runtime. Sorting via Code Enumerates methods and properties that allow you to sort Tree List data programmatically. Custom Sorting Learn how to implement custom sorting algorithms for individual columns.

Filtering

Data filtering is an essential requirement for most software applications. The Tree List Suite is packed with numerous filtering features, so that you can deliver a solution that best meets your customer’s requirements. Microsoft Excel Style Filter Dropdowns The simplest end-user filtering tasks can be accomplished using Filter Dropdown Lists. These lists mimic the filtering UI implemented in Microsoft Excel. Automatic Filtering Row The Auto Filter Row is a row, displayed above all other nodes, which allows end users to filter data by entering filter values within its cells. Advanced Filter Editor Dialog With this dialog, you will be able to build filter criteria of any complexity - create any number of conditions and combine them in any manner using any logical operator. Filtering in Code Filtering using an event allows you to create a filter of any complexity, and hide any nodes you want from the screen.

Summaries

The Tree List control provides a summary feature for calculating the value of an aggregate function over column values. This section lists the available summary types and describes methods of formatting the displayed summary. It also contains a brief description of end-user capabilities for configuring and using summaries. Summary Types Enumerates various summary types available in the Tree List control. Total Summaries This topic describes how to implement total summaries calculated against all or only root nodes. Group Summaries Contains information related with setting up group summaries, calculated for each group of nodes that have the same parent. Custom Summaries This topic illustrates how to implement custom aggregate functions. Formatting Summary Values Learn how to format a summary’s text and change the appearance of summary values.

Formatting Cell Values

The Tree List gives you the ability to format column values in display mode (when in-place editors are not active). This section lists which members can be used to format values, provides links to the documents that describe the formatting mechanism and provides task-based examples. Formatting Approaches Briefly describes formatting approaches available for the Tree List control. Members that Support the Formatting Mechanism Enumerates properties that affect cell formats. Format Specifiers Format specifiers are symbols that specify the way data is formatted during its conversion to a string. This topic describes frequently used standard and custom format specifiers used to format numeric and date/time values. Composite Formatting The Composite Formatting feature allows you to add custom text to the output formatted string. Custom Formatting The Custom Formatting feature allows you to format values that are neither numeric nor date/time and implement complex formatting of numeric or date/time values.

Drag-and-Drop Nodes

Users can drag nodes within a TreeList or between a TreeList and other controls. Refer to the following article for more details: Drag-and-Drop Tree List Nodes.

Other Concepts

Focus, Selection and Navigation In this section, you’ll find information on focus navigation and node selection. Appearances and Look And Feel Contains info on customizing the look and feel of the Tree List control and its elements.

Miscellaneous

• Design-Time Features
  This section covers the design-time features of the Tree List control.

• Context Menus
  The Tree List provides context menus for its elements that contain most used commands. There are context menus for column headers, group summary footers and the total summary footer. This section contains information on these menus and shows how to extend their capabilities.

• Printing the Tree List control
  Learn how to print the Tree List control using the DevExpress Printing library.

• Export and Import Data
  This topic describes the control’s export and import capabilities and limitations.

• End User Capabilities
  Topics in this section describe the operations available to end-users of the Tree List control.