[RESOLVED] [02/03] Adding a row in a datatable

[deien]

Hello Everyone!
I have a datatable that contains rows of data.
In what index exactly this command:

idt_DataTable.Rows.Add(lrw_NewRow)

adds a row into a datatable?

Because I tried to access each and every row of the datatable after i issue this command but it seems that the newly added row is not in it. How is this possible?

Please help me.. Thank you so much.

[jmcilhinney]

It doesn't insert it. If you want to insert it then you'd use the Insert method. The Add method simply adds the new item to the end of the collection, as the Add method of any and all collections do. That means its index will be idt_DataTable.Rows.Count-1.

[robertx]

This procedure inserts an array of objects into a specified row index. You will need to ensure that the length of the passed array is the same as the number of columns in your data table and that the values are validated to the columns' data types.

Public Sub InsertRowIntoDataTable(ByVal myDataTable As DataTable, ByVal objValues As Object(), _
                ByVal iIndex As Integer)

        Dim myRowItem As DataRow
        Dim i As Integer

        myRowItem = myDataTable.NewRow

        For i = 0 To objValues.GetUpperBound(0)
            myRowItem(i) = objValues(i)
        Next i

        myDataTable.Rows.InsertAt(myRowItem, iIndex)

    End Sub

[deien]

Thanks a lot guys for you help.
But if you don't mind, i still have another question to ask.

In deleting a row in a datatable.
How come that this code:

icls_DBManagement.idt_DataTable.Rows(ii_RowIndex).Delete()

and even this one:

icls_DBManagement.idt_DataTable.Rows.RemoveAt(ii_RowIndex)

does not remove the row in the datatable?
Because everytime that I add/insert a row to the index where the said row that i expect to be deleted, I get this exception msg:
"This row already belongs to this table."

Thanks.

[jmcilhinney]

That error message has nothing whatsoever to do with whether or not a row has been deleted. That error message is telling you that the DataRow object that you're trying to Add has already been added. You can't add the same row twice. When I say "the same row" I mean the same DataRow object, not two different DataRows with the same data.

Now, let's look at the code you posted. There is a BIG difference between deleting a DataRow in a DataTable and removing it. When you remove a row from a DataTable it is simply taken out, like it was never added in the first place. That has no effect whatsoever on the database so there's no way the corresponding record is going to be deleted from the database.

When you delete a row it is still in the Datatable but it is flagged as Deleted. When you then save the changes back to the database the corresponding record will be identified because it will have the same ID and it will be deleted. At that point the row will be implicitly removed from the DataTable as it's no longer required.

[deien]

Hey! Your so cool men! You really helped me out there! Thanks a lot..