how to Change the value(s) of a particular column in dataset or datatble returned

To Change the value(s) of a particular column in dataset or datatble in asp.net

For Each row As DataRow In Excelds.Tables(0).Rows
   Dim dtvView As DataView = ds.Tables(0).DefaultView
   dtvView.Item(RowNo).Row.Item("Desc") = "BlaBla.."
   ds.Tables(0).AcceptChanges()
   RowNo += 1
Next