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;