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Advanced TreeView for .NET

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4.91/5 (178 votes)
10 Jul 20064 min read 1.3M   33.8K   532   304
The TreeViewAdv control is designed to replace the standard .NET TreeView. It can do the same things, plus a number of advanced features like multi-selection or multi-column view.

TreeViewAdv in Multi-Column mode

Introduction

Working on several different projects, I was needed to display and edit hierarchical data. Of course, the first thing you will do is to use the standard .NET TreeView control. It works pretty well if you only need basic features. But learning this control to do something more complex is not an easy job. I could not find an alternative TreeView control which is free and fully meets my needs, so finally I decided to write my own.

The architecture of this control comes mainly from the Java Swing component, with some modifications. These are the key features of the TreeViewAdv control:

  • Model-View architecture - Will be covered in a separate section of this article.
  • Multiselection - Maybe the first limitation which you will find in the standard TreeView is that it’s not possible to select more then one node.
  • Unlimited number of controls for each node - You can display three icons + a CheckBox + two Labels.
  • Multicolumns - You can split the TreeView into several columns.
  • Load on Demand - Lazy load of child nodes.
  • Drag & Drop highlighting - Dynamically highlight the drop position.
  • 100% pure .NET code - No WinAPI is used in this control.

The following screenshots illustrate the TreeViewAdv features:

Drag&Drop highlighting

Multiselection

Using ComboBox to edit node

Model-View Architecture

I really like the Model-View pattern, and decided to use it in this control. The main idea of this pattern is to split the model (business object) from its visualization (control). If the model changes, it notifies the view by firing corresponding events. The view asks the model for details, if needed, and displays the changes. The model is described by ITreeModelInterface:

C#
public interface ITreeModel
{
    IEnumerable GetChildren(TreePath treePath);
    bool IsLeaf(TreePath treePath);

    event EventHandler<TreeModelEventArgs> NodesChanged; 
    event EventHandler<TreeModelEventArgs> NodesInserted;
    event EventHandler<TreeModelEventArgs> NodesRemoved; 
    event EventHandler<TreePathEventArgs> StructureChanged;
}

It’s very simple, and you need to implement only two methods. GetChildren should return the list of child nodes of the specified parent (empty for root nodes). IsLeaf method tells TreeView whether it should try to read child nodes of the specified parent. If you wish TreeView to dynamically track model changes, you need to use one of several events of the ITreeModel interface. The most common is the StructureChanged event, which cause the TreeView to fully refresh the specified node (or empty, for the whole model). For example, see the default implementation of the ITreeModel interface – the TreeModel class.

To specify the exact node in the model, TreePath class is used. It stores the path from the root to the node, in the FullPath property.

C#
public class TreePath
{
    public object[] FullPath{ get; }
    public object LastNode{ get; }
    public object FirstNode{ get; }
}

Using TreeView

In the source code, you can find two examples of how to use TreeViewAdv. The simplest way is to use TreeModel. All you need is to populate it with data and display it in the view:

C#
_model = new TreeModel();
_model.Nodes.Add(new Node("Root"));
_tree.Model = _model;

The Node class, which is used in TreeModel, contains only the ‘Text’ and ‘IsChecked’ properties. If you need additional properties, you can create an ancestor of the Node class and use it in TreeModel.

But to use the full power of the TreeViewAdv, you should create your own realization of the ITreeModel interface. See the folder browser presented in the source code, for an example.

Customizing TreeView

There are a number of properties which help to customize the look and behavior of the TreeView. The main ones are:

  • Model - Assign your model to this property to display it.
  • NodeControls - The collection of controls which will be used to visualize the model. You should provide at least one NodeControl in order to see the model.
  • LoadOnDemand - Read all child nodes at start-up or when the parent node expands.
  • SelectionMode - Single (no multi-selection), Multi, MultiSameParent (children of only one node can be selected).
  • UseColumns - Display data in columns or not.
  • Columns - The collection of columns. For each column, you can specify its header, width and alignment.

NodeControls

The standard TreeView can display only one icon, CheckBox, and Label for each node. In TreeViewAdv, you can use any number of NodeControl. All controls must inherit from the ‘NodeControl’ abstract class. Inherited classes should contain the code to draw the control and the code to respond on user actions – mouse and keyboard events.

NodeControl

This is the class diagram of all NodeControls provided by the library:

Class diagram

The BindableControl class provides a ‘DataPropertyName’ which is used in the control to read and write data to the node. All that you need is to specify the name of the property of your class.

Terms and Conditions

The TreeViewAdv control is provided as free software with open source code. You can use it in your applications if the original copyright is kept.

The latest version of TreeViewAdv is always available here. Please feel free to add your comments and suggestions in the forum there.

License

This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


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Comments and Discussions

 
QuestionHow to install the treeview Pin
Member 950484425-Apr-13 22:21
Member 950484425-Apr-13 22:21 
AnswerRe: How to install the treeview Pin
Ch4m3l30n17-Jun-13 13:30
Ch4m3l30n17-Jun-13 13:30 
BugGetting Error while working in combo box Pin
suresh111019837-Apr-13 21:36
suresh111019837-Apr-13 21:36 
Question2 different label for one node Pin
Member 986945021-Mar-13 22:51
Member 986945021-Mar-13 22:51 
QuestionMove Up & down functionality Pin
Ram Shelke16-Mar-13 23:23
Ram Shelke16-Mar-13 23:23 
AnswerRe: Move Up & down functionality Pin
William Winner18-Mar-13 2:42
William Winner18-Mar-13 2:42 
QuestionTreeview binding in database Pin
WebMaster19-Dec-12 0:39
WebMaster19-Dec-12 0:39 
QuestionAdd Node after a node Pin
PapyRef29-Nov-12 11:07
professionalPapyRef29-Nov-12 11:07 
I want to add node after a node on right button mouse click.
Is it possible ? How can I do that ?

C#
private void treeViewCmd_NodeMouseClick(object sender, TreeNodeAdvMouseEventArgs e)
        {
            if (e.Button == MouseButtons.Right)
            {
// How can I a node after this node click ?
            }
        }

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Suggestion[My vote of 2] Lack of examples... Pin
Niyazi Yarar23-Nov-12 12:25
Niyazi Yarar23-Nov-12 12:25 
GeneralMy vote of 5 Pin
Simon_12-Nov-12 6:52
Simon_12-Nov-12 6:52 
QuestionExpand Node Pin
Kenneth Psaila5-Oct-12 1:45
Kenneth Psaila5-Oct-12 1:45 
QuestionShow/Hide TreeNode Pin
mccallug3-Oct-12 6:14
mccallug3-Oct-12 6:14 
QuestionScrolling bug Pin
are_all_nicks_taken_or_what18-Sep-12 5:07
are_all_nicks_taken_or_what18-Sep-12 5:07 
NewsRe: Scrolling bug Pin
Niyazi Yarar24-Sep-12 3:44
Niyazi Yarar24-Sep-12 3:44 
QuestionHangs in FindModel() Pin
are_all_nicks_taken_or_what18-Sep-12 4:56
are_all_nicks_taken_or_what18-Sep-12 4:56 
AnswerRe: Hangs in FindModel() Pin
are_all_nicks_taken_or_what18-Sep-12 5:03
are_all_nicks_taken_or_what18-Sep-12 5:03 
QuestionCPOL license terms Pin
Barbara Evans14-Aug-12 23:18
Barbara Evans14-Aug-12 23:18 
QuestionRefreshing a node with out collapsing the tree Pin
David Koenig12-Jul-12 20:12
David Koenig12-Jul-12 20:12 
AnswerSet the Startup Project to SampleApp to avoid exception "Assembly doesn't contain any UserControl types." Pin
David Deley6-Jul-12 19:01
David Deley6-Jul-12 19:01 
QuestionVertical Column Headers Pin
MatthysDT6-Jul-12 0:24
MatthysDT6-Jul-12 0:24 
QuestionExport to CSV or Excel Pin
ksanghavi21-Jun-12 10:39
ksanghavi21-Jun-12 10:39 
QuestionSynchronize scrolling? Pin
denciaq31-May-12 20:57
denciaq31-May-12 20:57 
AnswerRe: Synchronize scrolling? Pin
Murdahl23-Jul-13 1:06
Murdahl23-Jul-13 1:06 
GeneralMy vote of 5 Pin
korolevsa14-Apr-12 3:26
korolevsa14-Apr-12 3:26 
QuestionTrouble Downloading Pin
Jason Gauthier10-Apr-12 11:10
Jason Gauthier10-Apr-12 11:10 

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