The problem is now, that the error-symbol (and the error text) is not displayed (in the cell). Cancel the cell looses the focus and error-symbol is displayed.How can I achieve that the cell remains in edit mode and the error-symbol is displayed too?
You can validate data by handling the Cell Validating event, which is raised by the Data Grid View when the current cell changes.
Could you strip only a part of your code and send it as a small example to allow us looking into this issue?
In order to be able to send us your project, you have to open a new support ticket.
I have tested the Row Validated event once again and it is thrown as expected when Rad Grid View loses focus.
I used Q3 2010 SP1 (2010.3.10.1215) version for my tests.