there are examples of adding textboxes and checkboxes in the cell of the grid
have a look at these demos:
http://demo.aspnetawesome.com/GridSpreadsheetDemo
http://demo.aspnetawesome.com/GridCheckboxesDemo
http://demo.aspnetawesome.com/GridDemo/CustomFormat
also, if you want something like inline editing have a look at this demo:
http://demo.aspnetawesome.com/GridNestingDemo#In-nest-editing-grid
have a look at these demos:
http://demo.aspnetawesome.com/GridSpreadsheetDemo
http://demo.aspnetawesome.com/GridCheckboxesDemo
http://demo.aspnetawesome.com/GridDemo/CustomFormat
also, if you want something like inline editing have a look at this demo:
http://demo.aspnetawesome.com/GridNestingDemo#In-nest-editing-grid