You can merge the duplicate cells (based on the value) for the particular column of Grid by using ‘dataBound’ event. At the same time, you can also merge the duplicate cells for particular column while exporting by using the
excelQueryCellInfo event for Excel/CSV and
pdfQueryCellInfo event for PDF exporting.
In the below demo, the duplicate cells are merged for the
OrderID column in Grid view and its exporting.