Hi Shirley,
Thank you for posting your query to us.
Resize the column by user.
By default GridDataBoundGrid allows you to resize the column by dragging the column header at run time. Please refer the video:
http://www.syncfusion.com/support/user/uploads/videocolumn_1e4d7710.zipIf I misunderstood your requirement please explain me in detail.
Regard,
Jisha