TTreeView programatically reaching subitems based on parents [SOLVED]

[vargatam77]

Hey again. I thought TTreeView will be a good object for this but obviously it is not... I need to create a multilevel visual list, just like ttreeview, except I would need to access nth parent's nth child's nth child, which in a world of a multilevel TListItems would be friggin easy, except TListView has a FLAT itemlist so TListView.Item[2].Items[1].Items[0] is not the 3rd parents sendond child's first child. ohh how easy it would be. Any out of the box solution for this without threading thorough the tree manually?
Cheers

[Khrys]

You can access child nodes in a non-flattened way using TTreeNodes.TopLvlItems.
TTreeView.Items.TopLvlItems[2].Items.TopLvlItems[1].Items.TopLvlItems[0]  does what you expect, although it's pretty verbose.

[vargatam77]

Ahh, well, as long as it works.. its perfect, thanks. I have even seen toplvlitems but i though it is about top level. silly me of course on every level the toplevel is that level thanks again

[wp]

If I understand the question correctly I'd implement NthChild and NthParent as node methods using a class helper:

Code: Pascal  [Select][+][-]

1. type
2.   TTreeNodeHelper = class helper for TTreeNode
3.   public
4.     function NthParent(N: Integer): TTreeNode;
5.     function NthChild(N: Integer): TTreeNode;
6.     function NthSibling(N: Integer): TTreeNode;
7.   end;
8.  
9. function TTreeNodeHelper.NthChild(N: Integer): TTreeNode;
10. var
11.   i: Integer;
12. begin
13.   Result := Self;
14.   if Result <> nil then
15.     for i := 1 to N do
16.       if Result.HasChildren then
17.         Result := Result.GetFirstChild
18.       else
19.       begin
20.         Result := nil;
21.         exit;
22.       end;
23. end;
24.  
25. function TTreeNodeHelper.NthParent(N: Integer): TTreeNode;
26. var
27.   i: Integer;
28. begin
29.   Result := Self;
30.   if Result <> nil then
31.     for i := 1 to N do
32.       if Result.Parent <> nil then
33.         Result := Result.Parent
34.       else
35.       begin
36.         Result := nil;
37.         exit;
38.       end;
39. end;
40.  
41. function NthSibling(N: Integer): TTreeNode;
42. var
43.   i: Integer;
44. begin
45.   Result := Self;
46.   if result <> nil then
47.     for i := 1 to N do
48.       if Result.GetNextSibling <> nil then
49.         Result := Result.GetNextSibling
50.       else
51.       begin
52.         Result := nil;
53.         exit;
54.       end;
55. end;

Then you can find the 3rd parent's 2nd child's 1st child by successive calls:

Code: Pascal  [Select][+][-]

1. function TForm1.ButtonClick(Sender: TObject);
2. begin
3.   TreeView1.Selected := TreeView1.Selected.NthParent(3).NthChild(2).NthChild(1);
4. end;

This combination, however, is rather trivial because going towards the root by 3 generations then back by 2 and then 1 generation, always via the first sibling, ends at the starting node... Maybe I am misunderstanding something. Therefore I also added a NthSibling method.

See a sample project in the attachment

[vargatam77]

If I understand the question correctly I'd implement NthChild and NthParent as node methods using a class helper:

See a sample project in the attachment

Thanks but toplvlitems have solved the issue. I simply needed to be able to access elements of a level by their index within their own respective level. for example, i query alsa for audio devices available, i save them, i will only know their indexes on the level of cards. then i iterate through their profiles, again i will only know which card has which profiles etc. to find one i need to be able to see each level separately like 2nd card's 3rd profile. this works well with toplvlitems, so no need for any further manual implementation... thanks anyway, i still appreciate trying to help me.