How to cascading combboxes inside Datagridview

Hi all,

Using C# ,how can i build 3 comboboxes for example to display Country - City - School cascadingly converting datagridview column type to combobox , On form design i can bind all comboboxes successfuly but when i try that using datagridview it does not display real data (or you can say cascaded and filtred data), I think you may understand my problem i tryed to search but i could not finally resolve my problem so here i need clearful solution code for this problem.

Thanks.