More information.

I made InitialDataBindDepth = 1 (instead of  0). This seems to stabilise the grid again, although I still get the error shown int he attached screen shot occasionally.

After testing I found that if I WAITED for the ajax animation to clear when expanding or collapsing a band, everything was fine. If however i clicked the linkto reverse my action before the grid had finished whatever internal operations were in progress - I get the error.

This is different again, but it seems that something is off when dealing with a lot of data and a complex display (and impatient users!) and it causes a variety of errors.

I upgrade my system to the most recent patch for 2010.1, and the problem is now quite consistent - it happens the SECOND time any band is opened, and every time after that. none of my server side code runs the second+ times, so i asume its pulling the data from a cache somewhere, and losing something in the process...

Is there some way I can force the grid to re-fetch the data for a child band each time its expanded to attempt to pin this down some more?

Apologies for the delay.

The issue is still ongoing. I cn preproduce it within the Visual Studio IDE - simply open and close a band as few as 2 times can trigger the first error reported ont he thread.

I've attached a screenshot of what a typical pagelooks like when a band is opened. the dispalyd one will crash the second time I attempt to open it (I can go and open other bands and come back to it and it will still crash)

i've attached the code for the form, however its part os a LARGE system.key points:

- I'm using object data sources (internally stored procedures retrieve data and populate objects)

- Most of the fields are nullable, particularly string, date and the percentage values

- there are a number of dropdown editors being used in each band. Each one consists of Key/description lists (using my own object type).

- I am using the server rowinitialise event to customise the formatting of one column according to the data present. Each row in each band can have unique formatting for this column.