I have seen posting for this error message couple of times but really there was no explaination or solutions. So i am posting this problem of mine.

I have a wingrid with multiple columns and i have pair of columns with parent child behaviour.In the same grounds as State and City. But the requirement for me is parent child population of columns should work in both directions and also i should allow users to pick empty or blank in both the columns. By both directions i mean if i pick North Carolina as "STATE" then i will get the filter list of cities in "CITY" column.I would have list of all states(including blank) in first column and list of all cities(including blank) in second column and if i pick Charlotte as city then "STATE" will be picked as North Carolina for you in "STATE" column.

I was able to get it work by implementing code in AfterCellListCloseUp and AfterCellUpdate events. But I have problem when i choose an item from any one of drop down list and then select blank, i get the following error "Unable to update the data value: Value in the editor is not valid" and this error doesnt get invoked by any of the events i use when a value in cell is changed.So i trapped this exception in Error event of the grid and handled it amicably but it leads to another problem where the whole grid freezes and i am not able to scroll unless i go back and repick an item other than blank from the dorp down list.

Any suggestions and solutions is greatly appreciated.

Thanks in advance