Hi Xuemei,
Searching our Direct Trac database for instances of this error does show a few. The problem occurred for two reason. First one is multithreaded situations where there are calls into the grid that are not protected by grid.InvokeRequired checks. So, if you are using multithreads, you need to make sure there are no unprotected calls in the grid from a thread other than the thread that created the grid. Second one is GridRangeInfo.InternalCells() method. This GridRangeInfo.InternalCells() method problem has been resolved in Essential Version v3.2 and above, can you please try in any one of our latest version? There has been a change in the GridRangeInfo class to avoid an exception:
// From 3.2 release notes
*Added a check for top < 0 || left < 0 in GridRangeInfo.InternalCells to avoid exception being thrown.
Here is the modified GridRangeInfo.cs where we added a check for top < 0 || left < 0 in GridRangeInfo.InternalCells to avoid exception being thrown.
Best regards,
Haneef