Right Bonnie, I hate to admit it, but you are right. It works without the newrow. Thanks.

>Hey Marc,
>
>You don't need to do a .NewRow() before you do the .ImportRow().
>
>~~Bonnie
>
>
>>Hey Bonnie,
>>
>>You're right. You do need to issue a odt.newrow though before you odt.importrow, becasue the latter does not add rows.
>>
>>Thank you very much for your help.
>>
>>This seems to work as expected:
>>
>>

>>
>>    Public Sub testDatarows()
>>        Dim oDt As New DataTable
>>        oDt.Columns.Add("Field1", GetType(String))
>>        oDt.Columns.Add("Field2", GetType(String))
>>        oDt.Columns.Add("Field3", GetType(String))
>>        Dim odr As DataRow = oDt.NewRow
>>        odr("Field1") = "value 1"
>>        odr("Field2") = "value 2"
>>        odr("Field3") = "value 3"
>>        oDt.Rows.Add(odr)
>>        oDt.NewRow()
>>        oDt.ImportRow(odr)
>>        oDt(oDt.Rows.Count - 1)("Field3") = "value 4"
>>        For Each odr In oDt.Rows
>>            Debug.Print(odr("Field1") & "- " & odr("field2") & "-" & odr("Field3"))
>>        Next
>>    End Sub
>>

>>
>>>Hi Marc,
>>>
>>>The only thing that will allow you to do a similar kind of thing is the DataTable.ImportRow() method. Depending on how much you have to do this sort of thing, it may or may not be helpful. It would work something like this:
>>>
>>>

>>>    Public Sub testDatarows()
>>>        Dim oDt As New DataTable
>>>        oDt.Columns.Add("Field1", GetType(String))
>>>        oDt.Columns.Add("Field2", GetType(String))
>>>        oDt.Columns.Add("Field3", GetType(String))
>>>        Dim odr As DataRow = oDt.NewRow
>>>        odr("Field1") = "value 1"
>>>        odr("Field2") = "value 2"
>>>        odr("Field3") = "value 3"
>>>        oDt.Rows.Add(odr)
>>>
>>>        ' will add a new row
>>>        oDt.ImportRow(odr)
>>>        ' then change the newly added row
>>>        oDt.Rows(dt.Rows.Count-1).Items("Field3") = "value 4"
>>>
>>>        For Each odr In oDt.Rows
>>>            Debug.Print(odr("Field1") & "- " & odr("field2") & "-" & odr("Field3"))
>>>        Next
>>>    End Sub
>>>

>>>
>>>~~Bonnie
>>>
>>>
>>>
>>>>Consider the following code
>>>>

>>>>    Public Sub testDatarows()
>>>>        Dim oDt As New DataTable
>>>>        oDt.Columns.Add("Field1", GetType(String))
>>>>        oDt.Columns.Add("Field2", GetType(String))
>>>>        oDt.Columns.Add("Field3", GetType(String))
>>>>        Dim odr As DataRow = oDt.NewRow
>>>>        odr("Field1") = "value 1"
>>>>        odr("Field2") = "value 2"
>>>>        odr("Field3") = "value 3"
>>>>        oDt.Rows.Add(odr)
>>>>        odr("Field3") = "value 4"
>>>>        oDt.Rows.Add(odr)
>>>>        For Each odr In oDt.Rows
>>>>            Debug.Print(odr("Field1") & "- " & odr("field2") & "-" & odr("Field3"))
>>>>        Next
>>>>    End Sub
>>>>

>>>>It breaks at the second
>>>>

>>>>oDt.Rows.Add(odr)
>>>>

>>>>
>>>>throwing an exception : {"This row already belongs to this table."}
>>>>
>>>>Is there a way around this besides issuing a new
>>>>

>>>> odr = oDt.NewRow
>>>>

>>>>
>>>>and copy and pasting the assignments of the two first fields?