Compare values in datatable using asp.net

I want to test to see if the time in date changes.  If it does i want to write out a blank line.   I can write out a blank line just fine but I need to know how to compare the timein values to see if they change each time.

Thank you


dim query
query="select eh.recordid, firstname + ' ' +  lastname as name, timein, timeout, description from employeehours as eh inner join employeelist as el on eh.employeeid = el.employeeid inner join masterjobcodelist as mjc on eh.jobcode = mjc.jobcode where firstname = 'Justine' and lastname = 'Cleary' and timein  > CONVERT(datetime, '" & strCurrentdate & "', 102) order by timein "
                 
 Dim da As SqlDataAdapter = New SqlDataAdapter(query, objconn)
dim Tbl = new DataTable()
da.Fill(Tbl)
Tbl.columns.add("columnNames")
dim i
dim cou as integer = Tbl.Rows.count()
dim objRow as datarow
'Get the time in date
                                       
while i <> cou
   ' Adding rows
   objRow = Tbl.newrow()
   'objRow("columnNames") = ...
   Tbl.rows.add(objRow)
   i = i + 1
end while

dgAddressBook.DataSource = Tbl        
dgAddressBook.DataBind()