>>>Select all works, as does unselect all because those cases are handled as checkbox events. I am now dealing with a scenario where if a user selects too many items I clear all selections programmatically and prompt for fewer selections, just cannot figure out how to clear the checkbox of the 'tick'.
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>>Is your Checkbox column bound to the data? If yes, how and then you update the underlying data?
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>Our checkbox column is bound to a boolean column that is added to the datatable at runtime. We just loop through the table setting the column as appropriate.

I'm not sure I get it. Can you show some code?

In my case I have Approved field in the SQL Server table. I want to be able to Select All/Unselect All and I also want automatic update behind the scenes when I click on the checkbox in a grid.