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TriStateTreeview in VB.NET

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19 Jan 20062 min read 180.1K   2.3K   40   39
A VB.NET implementation of a treeview with 3-state checkboxes using state image list

Introduction

The TreeView with checkboxes implemented in the .NET Framework (property TreeView.CheckBoxes = True) allows only 2 states (TreeNode.Checked = True or False). The implementation presented here:

  • Allows to use the state image list that is not directly available in the .NET Framework implementation.

  • Allows 3 states (4 including the state none) for a node: checked, unchecked, indeterminate.

  • Implements the logic to set the proper state of parents and children when the user changes the state of a node: it selects all children when the parent is selected, and set the state of the parent(s) to checked, unchecked or indeterminate depending on the number of children selected (all, none, etc.).

I have seen other TriState implementations in the C# section but they use the image list, not the state image list, for checkboxes and therefore doesn't allow to have icons and checkboxes for nodes at the same time.

Using the code

I have derived a TriStateTreeView class from the base TreeView class. This new class needs an additional state image list with icons for the 4 states: none, unchecked, checked, indeterminate (in this order).

The state image list is passed in the constructor:

VB.NET
m_ctlTriStateTreeView = New TriStateTreeView(Me.StateImageList)

A new enum type is provided to specify the state of a node:

VB.NET
Friend Enum CheckBoxState
   None = 0
   Unchecked = 1
   Checked = 2
   Indeterminate = 3
End Enum

To add nodes to the treeview, you can use the AddTreeNode helper function of the TriStateTreeView class:


VB.NET
objTreeNodeRoot = m_ctlTriStateTreeView.AddTreeNode( _
   m_ctlTriStateTreeView.Nodes, "My Computer", _
   IMG_COMPUTER, CheckBoxState.None)

To get the state of a node you use the GetTreeNodeState function of the TriStateTreeView class:


VB.NET
Friend Function GetTreeNodeState(ByVal objTreeNode As _
   TreeNode) As CheckBoxState

To set the state of a node you use the SetTreeNodeState function of the TriStateTreeView class:


VB.NET
Friend Sub SetTreeNodeState(ByVal objTreeNode As _
    TreeNode, ByVal eCheckBoxState As CheckBoxState)

Points of Interest

The code intercepts the MouseUp and KeyUp events to change the state of a node (when clicking with the mouse or pressing space). Also, the code prevents expanding or collapsing a node double-clicking on the state image.

History

  • 27-April-2004: Initial version.

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



Comments and Discussions

 
GeneralRe: Check Boxes not showing up in my project Pin
crazytom27-Jan-08 8:27
crazytom27-Jan-08 8:27 
GeneralRe: Check Boxes not showing up in my project Pin
khendric5-Mar-08 3:32
khendric5-Mar-08 3:32 
QuestionProblems with this class Pin
jonmach17-Nov-07 1:05
jonmach17-Nov-07 1:05 
AnswerRe: Problems with this class Pin
jonmach17-Nov-07 8:18
jonmach17-Nov-07 8:18 
AnswerRe: Problems with this class Pin
madmax824-Aug-10 3:02
madmax824-Aug-10 3:02 
Generalpocket pc project Pin
rabosa20-Jun-07 23:58
professionalrabosa20-Jun-07 23:58 
GeneralBeforeCheck Issue Pin
thierry_anthony13-Apr-07 7:30
thierry_anthony13-Apr-07 7:30 
GeneralPopule windows root [modified] Pin
mpdesign11-Feb-07 13:48
mpdesign11-Feb-07 13:48 
QuestionTreeview state problem Pin
Achintya Jha25-Oct-06 5:49
Achintya Jha25-Oct-06 5:49 
AnswerRe: Treeview state problem Pin
priman_p27-Sep-09 21:31
priman_p27-Sep-09 21:31 
GeneralLoadOnDemand does not work Pin
devnet24718-Feb-06 23:35
devnet24718-Feb-06 23:35 
GeneralVery nice however... Pin
vbinfo31-Jan-06 4:56
vbinfo31-Jan-06 4:56 
GeneralRe: Very nice however... Pin
Carlos J. Quintero31-Jan-06 5:17
Carlos J. Quintero31-Jan-06 5:17 
GeneralRe: Very nice however... Pin
devnet24713-Feb-06 12:31
devnet24713-Feb-06 12:31 
GeneralRe: Very nice however... Pin
Newton Burgos5-Aug-06 16:54
Newton Burgos5-Aug-06 16:54 
GeneralGreat Job Pin
Paul Conrad24-Jan-06 16:54
professionalPaul Conrad24-Jan-06 16:54 
GeneralMissing exe/dll Pin
Jonas Beckeman18-Jan-06 11:17
Jonas Beckeman18-Jan-06 11:17 
GeneralRe: Missing exe/dll Pin
Carlos J. Quintero18-Jan-06 22:24
Carlos J. Quintero18-Jan-06 22:24 
GeneralGreat !! Pin
jeromesubs18-Aug-05 5:04
jeromesubs18-Aug-05 5:04 
Questionhow to do it in asp.net? Pin
steven_wong23-May-05 16:42
steven_wong23-May-05 16:42 
GeneralExcellent - but needed C++! Pin
skonopa28-Feb-05 9:34
skonopa28-Feb-05 9:34 
GeneralRe: Excellent - but needed C++! Pin
skonopa1-Mar-05 12:42
skonopa1-Mar-05 12:42 
GeneralRe: Excellent - but needed C++! Pin
Atlantys20-May-05 8:49
Atlantys20-May-05 8:49 
GeneralExpand and Check problem Pin
Patrick Mc.30-Nov-04 9:27
sussPatrick Mc.30-Nov-04 9:27 
GeneralThis is Great Pin
vblackaby21-Sep-04 7:50
vblackaby21-Sep-04 7:50 

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