An MSForms (all VBA) treeview

Pages in this article

  1. Features
  2. How To Use
  3. Examples

Features

Performance

Realistically a VBA form with all the controls we need for each node can’t be expected to match that of the compiled original. Even so we are surprised at what has been possible, albeit with considerable tuning and refining. Light testing suggests 1000 to 2000 nodes is quite feasible even in a typical five year old laptop, depending on the configuration of the treeview.

Cosmetics

The original has a wide variety of features and functionality. We have tried to replicate most of these, and added a few features of our own.

Checkboxes

The common controls treeview has a checkboxes option so you can check nodes. We ensured our treeview has that too.

A picture says more than a thousand words, so:

Checkboxes are possible and work
Checkboxes are possible and work!

Expand/collapse boxes or icons

By default we draw a rectangle with a plus or minus characters as text to mimic the expand/collapse boxes. You can also opt for expand/collapse icons. We have bundled XP and Win7 style expander icons in the demo form or you can customize your own as you wish:

 Expander icons are provided
Icons as expand/collapse buttons

Lines

The treeview from the common controls lib always shows lines to indicate the structure. With ours it is optional to show lines. The choice might be for aesthetic reasons, however a very large treeview will load significantly faster without lines so that might be an overriding consideration.

Choose whether or not to show lines
Choose whether or not to show lines

Icons

Again, let's just look at the picture!

Icons can be added
You can add icons too!

If you are familiar with the ImageList control we have incorporated a similar approach. You can store your images in a (hidden) frame and pass a reference to the frame, just as you would pass a reference to an ImageList to the common controls treeview. However your icon images could be stored anywhere. As long as you can retrieve a “StdPicture” handle for each icon and add it to a “collection” that’s all we need.

Label formatting

Label formatting is available to you with code as simple as:

cNode.Bold = True
cNode.BackColor = RGB(255, 255, 220)    ' pale yellow
cNode.ForeColor = RGB(180, 0, 0)    ' dark red

Make sure you do not use code like:

cNode.Control.BackColor = RGB(255, 255, 220)    ' pale yellow

When you are building the set of nodes, the controls of the treeview have not yet been created (this is done when .Refresh is called). Using the properties the node class itself exposes ensures those are applied when the nodes are created. Only once the treeview is fully initialised and refreshed you can access the properties of the cNode.Control.

In addition, the treeview will automatically pick up the default font settings of its parent (frame) control, so controlling appearance of the treeview starts as easy as setting properties of the frame you'll use to host the treeview. I'll explain this on the next page.

Functionality

We've already implemented quite some functionality. Here is what you can do "out of the box":

Function
Description

Collapsing and expanding

Clicking the expand/collapse buttons does as advertised: it expands or collapses the tree.

Navigation using mouse and keyboard

Navigation using mouse and keyboard works just like in the "old" treeview. Right and left arrow expand or collapse, up and down arrow move up or down the tree. Page-up and down just work.

Editing nodes

You can use F2 to edit a node. Double-clicking a node also puts it in edit mode. This option can be enabled or disabled by setting a property value.

Drag and drop

We're working on that.

Copying, moving (cutting) and pasting

Copy and move functions are built in, you can copy or move single nodes or entire branches. You can do that silently but we have also made it easy for you to trap user actions on the selected node, eg Ctrl-c, Ctrl-x, Ctrl-v. You can include your own code to validate the intended actions, eg only allow copy between similar levels, then instigate the copy or move.

Sort

An efficient sort routine has been devised especially for this treeview. Currently it only operates at a given node level, however options for sort order and text/binary are included.

Properties

There is quite a number of properties you can change. To give you an idea, some are listed below. There are more properties and methods, which are documented in the Excel download.

Property
Description
Remarks

Full Width

True: Node caption widths extend beyond the width of the treeview, makes for clear highlighting of the selected node and if backcolor's are applied.

False: label widths are 'autosized' to the text
If node icons are used an additional image control is created for use with 'full width'

A large tree using node icons will load faster if 'full width' is not applied.

NarratorReaderControl

To make sure the treeview works well with Windows Narrator and hence addresses the needs of the visually impaired, we've added this option as of version 26.5 (set to True by default). Set to True to make sure the active node is picked up by screen reader software.

Checkboxes

True: show checkboxes.
Press spacekey or click to change the value.

The check change event is trapped in the form, and the info label updated.

Allow Editing

User can manually edit the node.
Double click or press F2 on a selected node.

Key Enter to apply the edit or Esc to abort.

Show Lines

Whether or not to show lines may be a matter of aesthetics or needs depending on the tree.
Try experimenting with different indentation widths (see the spin button).

In a large tree start-up time will be considerably faster if lines are not shown.

Root button

True: the entire tree can be collapsed to the Root.
False: the tree can only be collapsed to the first level.

Expander icons

The expander buttons can be Labels with +/- characters toggled, or pairs of icons.
If icons are used the images must be available in the workbook, on a sheet or as in the demo hidden on the form.

The demo includes pseudo WinXP and Win7 Explorer type expander icons, but you can use any icons of your choice, or no icons.

Indentation

Default is 15 points

NodeHeight

The treeview already automatically adjusts its Node height to the Font size or checkbox size or Icon size, whichever is the larger.

It's probably best not to adjust Node height.

Font size

The font size and other default label properties are adopted from the parent frame.

Change at design time only.

RootNodes

The root nodes of the tree

Nodes

All Nodes of your tree

Methods

Method
Description
Remarks

ActivateNode

Activate a node based on the key.

Copy

Copies the node put on the 'clipboard'

Move

Move source node + children to destination node.

NodesClear

Equivalent to Treeview.Nodes.Clear.

NodeRemove

Remove Node, its children and grandchildren.

Refresh

Adds and displays all the controls for the Treeview for the first time. ALso displays and repositions node controls as required.

SetTreeExpansionLevel

Updates the expanded properties according to lLevel.
Called recursively.

TerminateTree

Removes the treeview from memory.
Must be called before your userform goes out of scope.

ScrollToView

Ensures the node passed to the method is scrolled into view.

Events

Currently we have made available a limited set of events:

Event
Descrription

Click event

Fires when you click any node.

Node check event

Fires when you click the checkbox of a node.

After label edit event

Fires after editing a label.

Key down event

Fires when you press a key. The demoform included in the sample project shows how to implement copy and paste.

Mouse events

All mouse events are pushed through using a single MouseEvents event.

Add your own events

It isn't hard to add your own events, e.g. it takes three steps to add a new event for a specific element of the tree:

  1. Add event to the clsNode class for the piece of the tree you need an event for, by using the dropdowns at the top of the code window. Make sure it then calls a Friend sub in the clsTreeView class.
  2. Add an Event declaration to the clsTreeView class (like shown above) and a friend sub that raises that event when called from clsNode.
  3. Add an event handler to your userform.

Next: using this treeview in your VBA project.

 


 


Comments

Showing last 8 comments of 78 in total (Show All Comments):

 


Comment by: Peter Thornton (27-9-2021 10:33:00) deeplink to this comment

Hi Mark,

You can adapt the code to include the double click event if you follow the comments starting under if you follow the comments starting under 'Event Click', near the top of clsTreeview. Then it's fairly straightforward to include the code to toggle expand/collapse in the event, either in your project or within the treeview classes.

FYI the pro version includes an optional property 'DblClickExpand' which does exactly what you ask, also the full range of events and much else.


Comment by: Mark C (8-10-2021 02:17:00) deeplink to this comment

Hi Peter,

Thank you for the instruction. :)

I notice there might be a bug with modal popup form.
With demo access file you provided,
1. creat frm01, set as pop up form, and modal mode as true
2. add a button on frm01, simply use it add code "DoCmd.OpenForm "frmDemo"
3. Open frm01 and click the button to open frmDemo; close frmDemo, and the whole access program will be minimized. It should just close frmDemo and leave frm01 on screen.
4. To advoid it, set frm01 modal mode as false; Or just delete subTreeView control from frmdemo.
I dont' know what is causing the problem. Could you have a check?

Thanks,


Comment by: Peter Thornton (8-10-2021 12:09:00) deeplink to this comment

Hi Mark,

I can reproduce what you describe, I'm not sure why that occurs either.

However this does not seem to occur with the 'pro' treeview, so it might be related to how the 'userform' is handled which is much improved in the pro version.

You are the first person in 8 years to notice this:)


Comment by: john bourne (8-1-2024 17:24:00) deeplink to this comment

I am using this in an application and it has fulfilled all my requirements.

Is there any print function/report?


Comment by: Jan Karel Pieterse (9-1-2024 10:10:00) deeplink to this comment

Hi John,

I'm afraid you will have to write your own printing routine :-)


Comment by: Steve (16-5-2024 00:03:00) deeplink to this comment

I would like to be able to turn off the checkboxes for certain levels of the tree. For example, I'd like checkboxes only for the lowest children. Is it possible to do this?


Comment by: Jan Karel Pieterse (16-5-2024 15:48:00) deeplink to this comment

Hi Steve,

You would have to modify the classes in the project to make that happen I'm afraid. Currently checkboxes are "all or nothing"


Comment by: Peter Thornton (20-5-2024 14:29:00) deeplink to this comment

Steve, FYI the Pro-Treeview has the option to apply checkboxes selectively. For example only show checkboxes on 'leaf' nodes, if that's what you mean by "...only for the lowest children".


Have a question, comment or suggestion? Then please use this form.

If your question is not directly related to this web page, but rather a more general "How do I do this" Excel question, then I advise you to ask your question here: www.eileenslounge.com.




To post VBA code in your comment, use [VB] tags, like this: [VB]Code goes here[/VB].