RE: Hierarchal data and tree views

Trent L. Taylor — Mon, 30 Oct 2006 14:52:41 GMT

TreeViews are a wonderful tool in .NET and we use them all over the place...however, though there are similarities between each use, the TreeView is always a little bit different, thus making it a little more difficult to have a hard and fast standard.

Here are some of the standards that we follow though. The best advice is to create recursive methods that build each of the nodes.

Private Sub LoadTree()
'-- Establish Locals
Dim loNode As TreeNode

'-- Clear the tree
MyTreeView.Nodes.Clear()

'-- Cycle through all of the parent records
If MyBO.MoveFirst()
Do
'-- Create the new root node
loNode = New TreeNode(MyBO.MyTitleField)

'-- Load any children nodes
LoadChildNodes(MyBO, loNode)
Loop While MyBO.MoveNext()
End If
End SUb

Private Sub LoadChildNodes(Byval ParentBO As BusinessLayer, Byval ParentNode As TreeNode)
'-- Establish Locals
Dim loNode As TreeNode
Dim loChildBO As New MyChildBO

'-- Load the child records
loChildBO.FillByParentPrimaryKey(ParentBO.PrimaryKey)

'-- Cycle through the child nodes
If loChildBO.MoveFirst()
Do
'-- Create the node
loNode = New TreeNode(loChildBO.TitleField)

'-- Add to parent nodes
ParentNode.Nodes.Add(loNode)

'-- Check for child nodes
If loChildBO.HasChildRecords Then
LoadChildNodes(loChildBO, loNode)
End If
Loop While loChildBO.MoveNext()
End If

'-- Clean Up
loChildBO.Dispose()
End Sub

Also, we generally create a class and store it in the tag property of each node so that when it is clicked we know exactly what to do. You can see a simple example of this in the samples that were installed with the framework. I think it is called Explorer Form Sample.

Hierarchal data and tree views

Greg McGuffey — Mon, 30 Oct 2006 14:38:20 GMT

I'm not sure if this is the best place for this question or in the BusinessObjects section...

I have several hierarchal data structures and would like to present them in a tree view. Some of these structures are from within a single table and some span multiple tables. I looking for any suggestions, guidelines on the best way to do this. I'm assuming that in any case I'm likely going to be getting a DataTable from a BO and manually building the tree, but maybe there is a better way.

So, the two types of hierarchies are:

1. parent child within a single table
2. parent child within a single table and with children within another table

So, how best to implement this sort of thing?

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RE: Hierarchal data and tree views

Hierarchal data and tree views