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#110: How can I increase a performance of standard TTreeView/TListView?

If you uses the TTreeView and/or TListView from Win32 page of default component palette, then you must know that if you have the large amount nodes, you have a very bad performance...

Of course, at same moment you'll try to find a some other third-party component that allow to work with your very large data but I want to give you the few hints which allows to increase a performance without any third-party components. Only using of optimized code.

Tip1:
if you need add a lot of nodes in same time (for example, after button click to load the 10000 nodes in tree from some source) then you must call:

yourTreeView.Items.BeginUpdate;
<your code for append of nodes>
yourTreeView.Items.EndUpdate;

This constuction will disable a repainting when you append the nodes - it's save a lot of time!

Tip2:
if you uses the some navigation by nodes, you must use the GetFirst and GetNext methods instead Items[i] using!

For example,

for i := 0 to yourTreeView.Items.Count-1 do
begin
  node := yourTreeView.Items[i];
  <process a node>
end;

For example, in own warehouse system I have a treeview with 5000 nodes which I load from Oracle8i resultset. After applying of these tips, the time of execution of procedure with append was decreased from 4-5 minutes to 15-20 seconds! Trust me:-)

I don't sure but I think that it's a bad work of Borland when team developed the envelope for Win's treeview/listview. But maybe I'm wrong.

PS: of course, if you have a very-very large data with few billions of nodes or after applying of tips above all the same you have a bad performance, you must use the virtual mode of control or really select the other third-party control. But I suggest to change the your inteface logic - to navigate thru few billions of nodes in same time is very hard task for user! Not only for you:-)

Published: December 28, 2000

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