Andrus,

I didn't get that from the help topic on the assign of RowCount... obviously it's doing something if it takes 8 seconds. Is it a linear or exponential time? How long do 10, 100, 1000, 10000 and 100000 rows take?

As far as faster goes do you really a million virtual rows at once? Can you just actually allocate them in blocks of say 1000 as you need?

>Your question is based on the wrong assumtotions.
>DataGridView VirtualMode is designed to *show* one screenful from large *virtual* data efficiently.
>OnCellValueNeeded is called whenever data is required.
>RowCount assignment line does *not* create day objects.
>
>Task Manager shows that this code does not require any measurable about of RAM if running.
>Here is better samle to reproduce this issue: