Author: Tomas Rutkauskas

How to check if a TTreeView is fully expanded or collapsed

Answer:
1   
2   function IsTreeviewFullyExpanded(tv: TTreeview): Boolean;
3   var
4     node: TTreenode;
5   begin
6     Assert(Assigned(tv));
7     if tv.items.count > 0 then
8     begin
9       node := tv.Items[0];
10      Result := true;
11      while Result and Assigned(node) do
12      begin
13        Result := node.Expanded or not node.HasChildren;
14        node := node.GetNext;
15      end;
16    end
17    else
18      Result := false
19  end;
20  
21  function IsTreeviewFullyCollapsed(tv: TTreeview): Boolean;
22  var
23    node: TTreenode;
24  begin
25    Assert(Assigned(tv));
26    if tv.items.count > 0 then
27    begin
28      node := tv.Items[0];
29      Result := true;
30      while Result and Assigned(node) do
31      begin
32        Result := not (node.Expanded and node.HasChildren);
33        node := node.GetNext;
34      end;
35    end
36    else
37      Result := false
38  end;