Append 1 DataTable to another

[Doug Bell]

Hi,
Is there a more efficient way to append the rows of a DataTable to a second
DataTable that has the same structure?

Currently I am using a For Next loop:

Dim drSource, drTarget as DataRow
For Each drSource in MySourceDataTable
drTarget =MyTargetDataTable.Rows.NewRow
drTarget = drSource
MyTargetDataTable.Rows.Add(drTarget )
Next dr

Thanks
Doug

 

[Jay B. Harlow [MVP - Outlook]]

Doug,
You can simplify your routine by using ImportRow instead of Rows.Add.

Something like:

For Each drSource As DataRow in MySourceDataTable
MyTargetDataTable.ImportRow(drSource)
Next dr

Note: A potential problem with your code:

drTarget =MyTargetDataTable.Rows.NewRow

Creates a new data row.

drTarget = drSource

Discards the newly created row in favor of the existing row.

Review the on-line help for differences between ImportRow & NewRow.

Hope this helps
Jay

 

[Doug Bell]

Thanks Jay,

That is much better.

It does, however, still need to loop through each row. Is there any way to
do a bulk import of the new rows?

Doug

 

[Cor Ligthert]

Dough,

Have a look at the datatable copy
http://msdn.microsoft.com/library/d...ml/frlrfsystemdatadatatableclasscopytopic.asp

However you cannot use this to append datarows. See for that the answer from
Jay.

I hope this helps?

Cor

 

[Jay B. Harlow [MVP - Outlook]]

Doug,
No, as Cor stated you can use DataTable.Copy to create an entire copy of a
DataTable (structure & data).

For a complete explanation of advanced features of Datasets, such as copying
& importing, I would strongly recommend you read David Sceppa's book
"Microsoft ADO.NET - Core Reference" from MS Press. As it is a good tutorial
on ADO.NET as well as a good desk reference once you know ADO.NET.

Hope this helps
Jay

 

[Doug Bell]

Jay,
Thanks for the tip, I will see if I can find that Book.

I have a Evangelos Petroutsos book that has helped quite a bit. We have
moved development to Dot Net but "we" did not factor in any get up to speed
time and I have found it a challenge but can see it is going to be very
worthwhile.

Current small project was meant to be deployed by the end of November! A
graph of progress would look like a yoyo.

Again thanks for you assistance.

Doug