Populate TreeView object in ASP.NET - asp.net

Question

I am new to TreeView in asp.net so any help regarding populating nodes would be great.
I have a DataTable that gets populated by a SQLAdapter. It contains:
-House- -Region- -Division-
Aurora House Arizona Central
Copper Hills Arizona Central
Arbor House DFW Central
Angelina House Timberland West
I want to know how to place data or create a TreeView that would look similar to this:
Selection
Corporate
Division
Region
House(s)
I have spent a lot of time researching about how to do this and I just cant wrap my head around it I dont know if its my data that it is in DataTable that makes it harder to do.
This is all going to be based on if the user has access to that particular Corporate/Division/Region/House so it I would like to have TreeView for admin show everything but for others show only what they have access to.
I dont think that is going to be a problem as long as I get the SQL that populates the Data Table correct. My concern also is the duplicate Regions/Divisions how do I also have them only appear once and not multiple times?
Thank you for all your help.
Nick

Answer 1

Basically, you'd ideally like to have an object (well, collection) that mimics the hierarchy that you want to present with the treeview.
I'm assuming the list that comes from the database is as you presented it in your question, and I'm assuming that "Selection" column contains
Maybe you can use Linq to create such hierarchical collection. Or maybe you don't even need to create that collection - maybe you can just go ahead and start building the treeview as you iterate your data records using - for example - linq and some looping.
There may be some more elegant ways, but something like this should work:
var selections = dt.Select(r => Convert.ToString(r["Selection"])).Distinct().ToList();
foreach (string selection in selections)
{
// create treeview node here; add to treeview
object selectionNode = null; // change type to treeview node type
var corporateList = dt.Where(r => Convert.ToString(r["Selection"]) == selection).Select(r => Convert.ToString(r["Corporate"])).Distinct().ToList();
foreach (string corporate in corporateList)
{
// create treeview node here; add it as a child to selectionNode
object corporateNode = null; // change type to tv node
var divisions = dt.Where(r => Convert.ToString(r["Selection"]) == selection && Convert.ToString(r["Corporate"]) == corporate).Select(r => Convert.ToString(r["Division"])).Distinct().ToList();
foreach (string div in divisions)
{
// create treeview node here; add it as a child to corporateNode
}
}
}

Answer 2

You can dynamically create a TreeView Control like this:
using (var db = new FORMS())
{
//Get Chapters from selected form
var query = from b in db.CHAPTERS
select b;
//Create treeview hierarchy
foreach (var rootItem in query)
{
TreeNode myNode = new TreeNode(rootItem.titulo, rootItem.id.ToString());
var childQuery = from b in db.SECTIONS
where b.idChapter = rootItem.id
select b;
//Add childs
foreach (var childItem in childQuery)
{
TreeNode myChildNode = new TreeNode(childItem.titulo, childItem.id.ToString());
myNode.ChildNodes.Add(myChildNode);
}
ChapterTreeView.Nodes.Add(myNode);
}
}
In this case I only have two levels for my TreeView Control, but you can nest as many as you want.