[AccessD] Drew - Help on TreeView Please

 >I will use a 'natural' key of sorts, which makes the node key more meaningful (and useful in later 
code).

OMG don't tell me you are going unbound at the same time!

;)

John W. Colby
www.ColbyConsulting.com


Drew Wutka wrote:
> No problem.  I just sent you the fix off list.  Correcting this
> particular error showed two more issues which I fixed too.  
> 
> Ironically, the issue wasn't technically a treeview issue.  However it
> did relate to how I personally use treeviews (so my example used this
> method).  The nodes of a treeview have to have a unique key. So if you
> have ten thousand nodes, each node 'key' must have unique to the other
> 9,999 nodes.  With a table, you would use an Autonumber, however, with a
> treeview branching out, I will use a 'natural' key of sorts, which makes
> the node key more meaningful (and useful in later code).
> 
> For example, let's take names:
> 
> 1  Bob
> 2  Dave
> 3  Tina
> 4  Drew
> 
> The numbers being the ID (autonumber field) from a table.  If we were to
> make a set of 'root' or top level nodes with these names, I would use
> the following as the key for that node(without the quotes): 'ID:1'
> (which would be for the 'Bob' node, 'ID:3' for the Tina node, etc.
> 
> Now if I want to include children nodes to the top level nodes, let's
> have a table of pets:
> 
> 1  Dog(s)
> 2  Cat(s)
> 3  Fish
> 4  Birds
> 5  Other
> 
> This data would be recorded in a PersonID PetID table, like this:
> 
> 1  1
> 1  3
> 4  2
> 4  3
> 
> So I would set the children nodes, to use the following Key (without the
> quotes) 'ID:1:1' or 'ID:4:3'
> 
> So the data above would look like this in a treeview (and I will put the
> node keys in parenthesis)
> 
> Bob (ID:1)
> --Dog(s)(ID:1:1)
> --Fish(ID:1:3:)
> Dave (ID:2)
> Tina (ID:3)
> Drew (ID:4)
> --Cat(s) (ID:4:2)
> --Fish  (ID:4:3)
> 
> The advantage of using 'natural' keys like this in a node, is that you
> can interact with a node in a few ways (clicking, dragging, etc.) and
> when you do so, you will have a node object, WITH a Key.  So by making
> the key relevant to what the node actually represents (while maintaining
> it's uniqueness) we can actually infer at least two critical pieces of
> information by Split()ing the Key property into an Array().  One, in
> this case, we know that if the Ubound of the split is 2, it's a top
> level node, and thus a Person, if it's 3, then it's a 'pet' node.  In
> VB, where I typically use Treeviews, it's very easy to have dynamic
> popup menus, so this ability of determining what type of node is being
> 'right clicked' allows me to popup different 'defined' menus.  The other
> piece of information is the key value to retrieve data (or set data) in
> the original tables.
> 
> I didn't put all this in the offlist email, but I figured I'd explain it
> a bit in case anyone is playing around with Treeviews.
> 
> Drew
> 
> -----Original Message-----
> From: accessd-bounces at databaseadvisors.com
> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Tina Norris
> Fields
> Sent: Monday, August 31, 2009 3:36 PM
> To: Access Developers discussion and problem solving
> Subject: Re: [AccessD] Drew - Help on TreeView Please
> 
> Thanks, I've sent it to you off-list via YouSendIt.  I really appreciate
> 
> your help.
> T
> 
> Drew Wutka wrote:
>> Sure, send it too me.  I'll look at it when I get the chance.
>>
>> Drew
>>
>> -----Original Message-----
>> From: accessd-bounces at databaseadvisors.com
>> [mailto:accessd-bounces at databaseadvisors.com] On Behalf Of Tina Norris
>> Fields
>> Sent: Monday, August 31, 2009 8:32 AM
>> To: Access Developers discussion and problem solving
>> Subject: [AccessD] Drew - Help on TreeView Please
>>
>> Hi Drew,
>>
>> After running into a number of frustrations working on the TreeView, I
> 
>> set it aside for a few months.  Now, I've come back to working on it. 
>>
>> Thanks very much for the example database you made.  It works
> perfectly,
>> so I used your code as a basis to build a practice database. 
>>
>> I am running into a runtime error  
>> "Run-time error '-2147217904(80040e10)':
>> No value given for one or more required parameters."
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