TTreeView

Code:

{type

  {: Callback to use to copy the data of a treenode when the

    node itself is copied by CopySubtree.

  @param oldnode is the old node

  @param newnode is the new node

  @Desc Use a callback of this type to implement your own algorithm

    for a node copy. The default just uses the Assign method, which

    produces a shallow copy of the nodes Data property. }

  TCopyDataProc = procedure(oldnode, newnode : TTreenode);

{: The default operation is to do a shallow copy of the node, via

Assign. }

procedure DefaultCopyDataProc(oldnode, newnode : TTreenode);

begin

  newnode.Assign(oldnode);

end;

{-- CopySubtree

-------------------------------------------------------}

{: Copies the source node with all child nodes to the target treeview.

@Param sourcenode is the node to copy

@Param target is the treeview to insert the copied nodes into

@Param targetnode is the node to insert the copy under, can be nil to

make the copy a top-level node.

@Param CopyProc is the (optional) callback to use to copy a node.

If Nil is passed for this parameter theDefaultCopyDataProc will be

used.

@Precondition  sourcenode <> nil, target <> nil, targetnode is either

nil or a node of target

@Raises Exception if targetnode happens to be in the subtree rooted in

sourcenode. Handling that special case is rather complicated, so we

simply refuse to do it at the moment.

}{ Created 2003-04-09 by P. Below -----------------------------------------------------------------------

}

procedure CopySubtree(sourcenode : TTreenode; target : TTreeview;

  targetnode : TTreenode; CopyProc : TCopyDataProc = nil);

var

  anchor : TTreenode;

  child : TTreenode;

begin { CopySubtree }

  Assert(Assigned(sourcenode),

    'CopySubtree:sourcenode cannot be nil');

  Assert(Assigned(target),

    'CopySubtree: target treeview cannot be nil');

  Assert((targetnode = nil) or (targetnode.TreeView = target),

    'CopySubtree: targetnode has to be a node in the target treeview.');

  if (sourcenode.TreeView = target) and

    (targetnode.HasAsParent(sourcenode) or (sourcenode =

    targetnode)) then

    raise Exception.Create('CopySubtree cannot copy a subtree to one of the ' +

      'subtrees nodes.');

  if not Assigned(CopyProc) then

    CopyProc := DefaultCopyDataProc;

  anchor := target.Items.AddChild(targetnode, sourcenode.Text);

  CopyProc(sourcenode, anchor);

  child := sourcenode.GetFirstChild;

  while Assigned(child) do

   begin

    CopySubtree(child, target, anchor, CopyProc);

    child := child.getNextSibling;

  end; { While }

end; { CopySubtree }

procedure TForm1.Button1Click(Sender : TObject);

begin

  if assigned(treeview1.selected) then

    CopySubtree(treeview1.selected, treeview2, nil);

end;