Question

I tried to use a TListView component to display rather large data lists (like 4000 rows large), and creating the list is incredibly slow – it takes something like 2-3 secs, which makes the UI all laggy and close to unusable.

I fill the TListView.Items inside a BeginUpdate/EndUpdate block, with only preallocated strings – I mean : I build a list of all strings to store (which takes no humanly noticeable time), then I put them in the TListView.

I wish to display the TListView’s content in vsReport mode with several columns.

The code looks like this :

MyList.Items.BeginUpdate;
for i := 0 to MyCount - 1 do
begin
  ListItem := MyList.Items.Add;
  ListItem.Caption := StrCaptions[i];
  ListItem.SubItems.Add(StrSubItems1[i]);
  ListItem.SubItems.Add(StrSubItems2[i]);
end;
MyList.Items.EndUpdate;

Is there some other hack I missed in the TListView component’s logic ? or should I just forget about using this component for performances ?

Answer 1

You can use listview in virtual mode. Have a look at the virtuallistview.dpr demo.