[AccessD] Tina's Treeview example

Wow, Drew!  Okay, I think I love it.  Now, I need to walk my way through 
all the code to make sure I understand it.  Thanks a bunch!
Tina

Drew Wutka wrote:
> Ok, the sample is at http://www.marlow.com/treeview.zip
>
>  
>
> In the database, there are three tables (to keep it simple).  tblSkills,
> tblVolunteers and tblVolunteerSkills.
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>  
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> The first two tables are ID and Name (SkillID and VolunteerID).  The
> third table has both id's and SkillLevel.
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>  
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> I put a few skills and two volunteers, Bob and Larry.
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>  
>
> There is one form, frmVolunteerSkills.
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> It has a Combobox (Combo2...sorry, should have renamed it, but was in a
> rush).  It displays the volunteers (with the bound column being the ID).
>
>  
>
> On the Onclick event, it runs a function 'BuildTreeView' and put's it's
> value (the volunteer ID) in the intVolunteerID argument.
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>  
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> That function opens a recordset from the skills table and creates the
> Nodes.
>
>  
>
> Ok, Before I continue, a few things to know about treeviews.  Treeviews
> are a control based around nodes.  Nodes can either be Root Nodes or
> Child Nodes.  You can also display check boxes or even pictures for each
> node.  On top of that, node 'labels' can also be edited (if you want),
> so you can even allow someone to change the text of something. If you
> want an example of how you could allow your user to edit the name of a
> skill from the treeview, let me know.  It takes a little bit of playing
> around with a treeview and it's node objects to get used to them, but
> once you do, it is a very powerful interface tool.
>
>  
>
> Back to BuildTreeView.  It builds a root node for each skill, and sets
> it's key to "ID:x" (x being whatever ID the Skill is).  It then builds
> three child nodes with the key of "ID:x:y" where y is 1 through 3 (the
> skill level).
>
>  
>
> It then opens another recordset from the tblVolunteerSkills, based on
> the VolunteerID.  It runs through that recordset 'checking' the nodes
> that are applicable (the root node (skill) and the child node (skill
> level), and as you can see in the code, it does this by using the values
> from the table being put in the ID:x and ID:x:y format. (It also expands
> any skill 'root node' that is selected already)
>
>  
>
> Now, the treeview itself is handling the data entry, it's doing this in
> tvwSkills_NodeCheck (so it does stuff whenever you 'check' a node).
> Kind of hard to write out what the logic is doing, but here's the gist,
> when you click on a root node (a skill), if you don't have a skill level
> selected, it really does nothing (I have commented out code where I was
> trying to uncheck the node then....wasn't working, and again, this was a
> quick and dirty example, there should be a way to uncheck the node, the
> problem is, stepping through the code, it would uncheck it, but when the
> code finished, the node rechecked itself....odd....).  But if it IS
> checked, so the user is 'unchecking' a skill, it unchecks it's child
> nodes (the skill levels), and deletes the appropriate record in
> tblVolunteerSkills. 
>
>  
>
> If you check a skill level, it unchecks any other skill level (so if
> skill level 1 for Cooking is checked, and the user checks skill Level 2
> for cooking, Skill Level 1 for cooking unchecks itself, so it gives the
> illusion of only being able to check one skill level....like a radio
> button option box would...), it then tries to 'update'
> tblVolunteerSkills and if no records return from that, it 'inserts' the
> appropriate record.  It also 'checks' it's parent root node.  
>
>  
>
> If you uncheck a skill level, it unchecks it's parent, and deletes the
> appropriate record from tblVolunteerSkills.
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>  
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> Like I said, this is a quick and dirty example, but it should show what
> you can do with a treeview, and should also satisfy your 'click happy'
> end user! ;)
>
>  
>
> Drew
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>
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