I have a weird performance issue with my ModalExtender using MS Ajax Toolkit, when I postback back to show the modal it takes near 10 seconds for it appear when my Gridview has about 1600 rows. If I page my Gridview to about 10 rows per page, the performance is acceptable, about a second to show..
Is this behavior normal? The speed is being affected by the amount of data displayed on my page.. Has anyone experienced this, if so what was your solution?
::edit:: When I postback I’m not rebinding to the gridview.
I’m willing to bet that the problem is that your GridView, with 1600 rows, is posting back a large ViewState. Check the size of the ViewState in your page source.
You can also use Fiddler (an HTTP proxy) to check the amount and content of data returned to the server.