How to auto expand all TTreeView nodes?

问题:

I want to expand tree on main form when application starts. How i can do it? I cant find corresponding property. C++ builder 2009.

回答1:

You simply need to call FullExpand() on the tree view.

回答2:

When adding treenode make its expanded property to true

you will find a property for the treeNode Object, set it yo true before add to list of nodes.

and also you can find a method for the treeView called ExpandAll

My Regards

---

try this code

//this will expand all nodes of Level and their parents
procedure ExpandTree(Tree: TTreeView; Level: integer);

  procedure ExpandParents(Node: TTreeNode);
  var
    aNode : TTreeNode;
  begin
    aNode := Node.Parent;
    while aNode <> nil do begin
      if not aNode.Expanded then
        aNode.Expand(false);
      aNode := aNode.Parent;
    end;
  end;

var
  aNode : TTreeNode;
begin
  if Tree.Items.Count > 0 then begin
    aNode := Tree.Items[0];

    while aNode <> nil do begin
      if aNode.Level = Level then begin
        aNode.Expand(false);
        ExpandParents(aNode);
      end;
      aNode := aNode.GetNext;
    end;
  end;
end;

//this will expand the Node and it's parents
procedure ExpandNode(Node: TTreeNode);
var
  aNode : TTreeNode;
begin
  Node.Expand(false);

  aNode := Node.Parent;
  while aNode <> nil do begin
    if not aNode.Expanded then
      aNode.Expand(false);
    aNode := aNode.Parent;
  end;
end;

and see the reference http://www.delphipages.com/forum/showthread.php?t=159148

My Regards

回答3:

There a number of Ways of doing this. The easiest would be

TreeView1.FullExpand;

as in the accepted answer - Alternatively

if TreeView1.items.GetFirstNode <> nil then
  TreeView1.items.GetFirstNode.Expand(True);

or

if TreeView1.items[0] <> nil then
  TreeView1.items[0].Expand(True);

The Expand method on a TTreeNode is useful if you want to fully expand from a particular node that is not the root node.