delete row from dataview

[Sam]

Hi,

As I loop through a dataview's records, I delete datarow based on a
condition. However I don't want to commit those deletions until the
loop ends. With a datatable, i would just set row.delete() and call
AcceptChanges when the loop ends. But how can I do that with a dataview
?

Thank you

[Cor Ligthert [MVP]]

Sam,

Don't mix up the words Delete and Remove in AdoNet.

Delete marks a datarow as to be Removed by an acceptchanges or an DA.Update.
Remove removes a datarow from a DataTable.

I am not sure what you are doing, because it seems strange to me, however
you will have a solution with this.
If you do by instance this.

DataTable.Accep tChanges 'assuming that al other rowstates can be set to this
drv(0).Delete
DataTable.Accep tChanges

Than the first row that fullfils the rowfilter will be removed.

Which is than the same as
DataTable.rows. remove(drv(0).r ow)

I hope this helps,

Cor

"Sam" <sa************ *@googlemail.co m> schreef in bericht
news:11******** **************@ i40g2000cwc.goo glegroups.com.. .

Hi,

As I loop through a dataview's records, I delete datarow based on a
condition. However I don't want to commit those deletions until the
loop ends. With a datatable, i would just set row.delete() and call
AcceptChanges when the loop ends. But how can I do that with a dataview
?

Thank you

[Sam]

Cor,
Thanks for replying.
I'm sorry but I don't understand your example. Maybe I haven't
explained properly what I want to do.
Watch this:

For each row as datarowview in myDataView

if my condition is met then
mark row to be removed
end if

Next

commit changes here, meaning remove the rows from myDataView.

Now, I've come up with a solution, which is to convert the dataview to
a datatable using ToTable function. Then I can use .Delete and
AcceptChanges on this datatable, and then reassign the datattable to be
the source for my dataview. I know it's a bit ackward but it's the best
I could come up with. Do you have a better solution ?

Sam

[Virgil]

Hi Sam,

If I understand your question correctly, you want to iterate through
the rows in a view, delete some of them (conditionally) , then commit
those deletes. Hopefully the code below solves your question.

Dim Row As DataRowView

For Each Row In View
If Condition = True Then
Row.Delete()
End If
Next
View.Table.Acce ptChanges()

[Cor Ligthert [MVP]]

Sam,

Sorry I forgot to answer that part, I was meaning something as Virgil wrote
however than extended with the RejectChanges if it not should be done.

http://msdn2.microsoft.com/en-us/lib...ctchanges.aspx

Be aware that you do before the AcceptChanges forever an update if that is
necessary, because your changes are by the AcceptChanges not anymore
recognisable.

I hope this helps,

Cor

"Sam" <sa************ *@googlemail.co m> schreef in bericht
news:11******** **************@ e56g2000cwe.goo glegroups.com.. .

Cor,
Thanks for replying.
I'm sorry but I don't understand your example. Maybe I haven't
explained properly what I want to do.
Watch this:

For each row as datarowview in myDataView

if my condition is met then
mark row to be removed
end if

Next

commit changes here, meaning remove the rows from myDataView.

Now, I've come up with a solution, which is to convert the dataview to
a datatable using ToTable function. Then I can use .Delete and
AcceptChanges on this datatable, and then reassign the datattable to be
the source for my dataview. I know it's a bit ackward but it's the best
I could come up with. Do you have a better solution ?

Sam

[Sam]

Hi,

Thank to both of you for helping me out.
Here's my code, base on what I had, mixed with Virgil's sample:

For Each row As DataRowView In dvOrig
'how many times to we have the QueryGroupId in the table
drResult = dvOrig.FindRows (row("QueryGrou pId"))
'if it appears more than once then add it to dtDest and
'delete it from dtOrig
If Not drResult.Length > 1 Then
row.Delete()
End If
Next

The issue occurs on the 3rd shot in the loop as it raises the
exception: There is no row at position 3 in the view.
This is because the row was marked as Delete, and now it tries to use
FindRows.
How can I get around this ?

[Cor Ligthert [MVP]]

Sam,

This in one of the good examples why you should do deleting in a collection
forever down to top.
(I did not look that well at the sample of Virgil)

For i as integer = mycollection.co unt-1 to 0 step -1
'the code
Next

Cor

"Sam" <sa************ *@googlemail.co m> schreef in bericht
news:11******** *************@i 40g2000cwc.goog legroups.com...

Hi,

Thank to both of you for helping me out.
Here's my code, base on what I had, mixed with Virgil's sample:

For Each row As DataRowView In dvOrig
'how many times to we have the QueryGroupId in the table
drResult = dvOrig.FindRows (row("QueryGrou pId"))
'if it appears more than once then add it to dtDest and
'delete it from dtOrig
If Not drResult.Length > 1 Then
row.Delete()
End If
Next

The issue occurs on the 3rd shot in the loop as it raises the
exception: There is no row at position 3 in the view.
This is because the row was marked as Delete, and now it tries to use
FindRows.
How can I get around this ?

[Sam]

Yes!!!!!!!!!!
Thank you so much Cor, it works !

Just one more question if you don't mind ! Before I delete the row, I
want to add it to another dataview. How can I do that, I can't figure
it out... Here's my code so far:

Dim drResult As DataRowView()
dvOrig.Sort = "QueryGroup Id"

For i As Integer = dvOrig.Count - 1 To 0 Step -1
drResult = dvOrig.FindRows (dvOrig(i).Item ("QueryGroupId" ))

If Not drResult.Length > 1 Then
'HERE I WANT TO ADD THE ROW TO ANOTHER DATAVIEW, WHICH
HAS THE SAME
'COLUMNS (SAME STRUCTURE) AS dvOrig.
dvOrig.Item(i). Delete()
End If
Next
dvOrig.Table.Ac ceptChanges()

[Cor Ligthert [MVP]]

Sam,

As I thought does there go something wrong,

A dataview is a view on a table. To delete it from a view, you only have to
change the part that is in the rowfilter from that.

Now you are removing the rows completely from your table. From your message
I understand now that, that is not the purpose.

So as sample

dim dv1 as new dataview(mytabl e)
dim dv2 as new dataview(mytabl e)

dv1.rowfilter = "City = 1)"
dv2.rowfilter = "City = 2)"

Now you have not to delete in your loop however something as

for i as integer = dv1.count -1 to 0
drv("City") = "2"
next

I hope this helps,

Cor


"Sa
m" <sa************ *@googlemail.co m> schreef in bericht
news:11******** *************@i 39g2000cwa.goog legroups.com...

Yes!!!!!!!!!!
Thank you so much Cor, it works !

Just one more question if you don't mind ! Before I delete the row, I
want to add it to another dataview. How can I do that, I can't figure
it out... Here's my code so far:

Dim drResult As DataRowView()
dvOrig.Sort = "QueryGroup Id"

For i As Integer = dvOrig.Count - 1 To 0 Step -1
drResult = dvOrig.FindRows (dvOrig(i).Item ("QueryGroupId" ))

If Not drResult.Length > 1 Then
'HERE I WANT TO ADD THE ROW TO ANOTHER DATAVIEW, WHICH
HAS THE SAME
'COLUMNS (SAME STRUCTURE) AS dvOrig.
dvOrig.Item(i). Delete()
End If
Next
dvOrig.Table.Ac ceptChanges()

[Sam]

This is not that simple. Here's what I'm trying to achieve.

I have two dataviews with same structure. They both have a field named
'QueryGroupId'. In dvDest, all the records have QueryGroupId = NULL. In
dvOrig, there are records which have the same QueryGroupId.

I'm trying to delete records from dvOrig where the QueryGroupId is
unique, that is, it does not appear more than once. But before I delete
this record, I want to move it to dvDest.

Therefore I can't use rowfilter, unless you know a way to get the
records that were rejected by the filter ?
Does it make it clearer ?