I had a DataGrid server control designed on one of my webpage that listed all item in one page, which worked ok, no problem. However, it started acting funny when I added paging feature. It worked no problem on the first set of pages, for exampe, the first 10 pages as default, and showed the first set of pages again when accessing the second set like 11-20. All property settings in DataGrid was correct and the trigger event was also set up as it is supposed to. Spent hours to try to find and defind what the problem is and finally looked into the settings in Web.Config file. Aha...that is why it happend. The value of sessionState was set as “Off”, which turns off the session state while the paging in DataGrid needs to save the data in local, so the proper setting for sessionState in order to get paging in DataGrid working is “InProc”. Once it's been reversed, everything started working as it is supposed to.
comment: the problem is due to some kind of lacking the basic knowledge of ASP.Net, which tells me that I should sit and read more books or documents about these basic sense. :)