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ComboBoxTree

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4.32/5 (22 votes)
2 Feb 20042 min read 154.8K   3.7K   66   33
A treeview control that drops down much like a combobox.

Sample Image

Introduction

The ComboBoxTree control expands on Gevik Babakhani's DropDown Treeview control. Nearly 85% of the code has been rewritten. This updated control provides the following enhancements:

  • Treeview can be sized beyond the width of its parents and the form.
  • The sizing grip functionality is more consistent with standard Windows sizing grips.
  • Node selection populates the box when it is a root node, the SelectionSeparator property assigns the separator (i.e. a SelectionSeperator that is a period '.' would generate something like: Node0.subnode1.subnode2.rootnode).
  • Better design-time support including the standard treeview WYSIWYG editor.
  • The selected node box is editable and accessible as a property - however there is no validation on this value when set manually.
  • Simplified, by using regions and less method calls.

Please feel free to post comments, questions or criticism. This is my first Windows control, so feedback is appreciated.

Background

I needed a control for a project that required multiple treeviews but had very limited form space. When I found Gevik's DropDown TreeView, I was relieved to find what I was looking for but soon ran into problems that required attention and hours of code updating.

Originally, I didn't intend to redistribute the updated control, but I wanted to give back as a way of saying thanks. Thanks goes out to The Code Project and the original author - thanks Gevik Babakhani ;-)

To use the control, simply add the ComboBoxTree.dll file to your toolbox and drop the control onto your form. The control should provide most of the treeview functionality you require.

Points of Interest

I was able to get around the "sizing beyond parent" problem by adding the treeview to its own borderless form. My next problem involved making the sizing grip work correctly. I was able to get this going by calculating the offset of the mouse within the sizing grip along with the absolute mouse position and the location of the form containing the treeview. My final big problem was the sizing grip when scroll bars showed. Disabling scroll bars wasn't a solution so my only alternative was to add a margin of space on the bottom and right-hand side. A bit different but definitely functional!

History

  • 01/26/04 Version 1.0 submitted.
  • 02/02/04 Version 1.2 submitted, changes include:
    • Text property is now overridden.
    • AbsoluteChildrenSelectableOnly property option now available, users can now select end nodes only or all nodes.
    • Public ValidateText method now available to validate manually entered text.
    • SelectionSeparator now called BranchSeparater.
    • Minor toolbox category changes.

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

 
GeneralI modified your project and update my GITHUB Pin
jash.liao26-Jul-18 20:59
jash.liao26-Jul-18 20:59 
BugSize Bug Pin
Member 1145332622-Dec-15 1:55
Member 1145332622-Dec-15 1:55 
QuestionNo NodeSelectEventHandler event? Pin
locketine17-Dec-12 14:07
locketine17-Dec-12 14:07 
AnswerRe: No NodeSelectEventHandler event? Pin
Member 1145332622-Dec-15 2:16
Member 1145332622-Dec-15 2:16 
QuestionCan't change size Pin
MVictorL18-Nov-12 22:09
MVictorL18-Nov-12 22:09 
AnswerRe: Can't change size Pin
jash.liao29-Jul-18 15:18
jash.liao29-Jul-18 15:18 
QuestionHandling the Enter key Pin
Member 390355925-Oct-12 10:55
Member 390355925-Oct-12 10:55 
I want to be able to select a node with the enter key. How would I do that?
AnswerRe: Handling the Enter key Pin
jash.liao29-Jul-18 15:17
jash.liao29-Jul-18 15:17 
QuestionHow to show image of the selected tree item in combobox Pin
Rui Frazao9-Jun-10 6:07
Rui Frazao9-Jun-10 6:07 
GeneralCheckbox With Every Node Pin
Farid_Bilal26-Feb-09 20:58
Farid_Bilal26-Feb-09 20:58 
QuestionHow to populate tree with data from datatable ? Pin
marcelo2312-Jul-08 3:49
marcelo2312-Jul-08 3:49 
QuestionHow can i get DropDownStyle like combobox? Pin
Mansoor Mehmood10-Apr-08 3:07
Mansoor Mehmood10-Apr-08 3:07 
GeneralBranchSeparator as String, DropDownHeight, ... Pin
fraveu27-Sep-07 9:53
fraveu27-Sep-07 9:53 
GeneralRe: BranchSeparator as String, DropDownHeight, ... Pin
fraveu27-Sep-07 9:55
fraveu27-Sep-07 9:55 
GeneralFlatStyle System Pin
jake07223-Aug-07 10:30
jake07223-Aug-07 10:30 
GeneralRe: FlatStyle System Pin
LAcike@sk30-Jun-08 23:40
LAcike@sk30-Jun-08 23:40 
GeneralAfterSelect event Pin
mayank_max4-Jun-07 6:50
mayank_max4-Jun-07 6:50 
GeneralRe: AfterSelect event Pin
mayank_max4-Jun-07 9:07
mayank_max4-Jun-07 9:07 
GeneralRe: AfterSelect event Pin
mayank_max4-Jun-07 9:13
mayank_max4-Jun-07 9:13 
GeneralRe: AfterSelect event Pin
JossGP11-Oct-07 23:41
JossGP11-Oct-07 23:41 
QuestionHow to sort the ComboBoxTree Pin
satisht23-May-07 20:18
satisht23-May-07 20:18 
GeneralNeed this in VB.net [modified] - no longer needed Pin
Vortran9-Oct-06 10:51
Vortran9-Oct-06 10:51 
GeneralBug Deteced !! Pin
H1berto Ferreira3-Jan-06 1:44
H1berto Ferreira3-Jan-06 1:44 
Generalform lostfocus problem Pin
TurboWang10-Mar-04 14:50
TurboWang10-Mar-04 14:50 
GeneralRe: form lostfocus problem Pin
Gabe Anguiano12-Mar-04 9:59
Gabe Anguiano12-Mar-04 9:59 

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