Drag n Drop DataRow from DataGridView to another

Thanks Sancler, it seems to work quite well.

One niggle I have is after a row has been selected and moved from dgvA, if I want to select another row, I have to click the dgvA twice before it selects the row. I've never noticed this behaviour before.

I've tried putting dgvA.Focus() in the dgvA_MouseEnter event but it doesn't help.
Any ideas?

>>
Any ideas?
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I'm sorry, right at the moment, no.  I might, with time to test more extensively than I've got at the moment, come up with something.  But that will be a few hours away.

Roger

I'm afraid this looks like (another) design problem with the DataGridView itself.  It appears to be a consequence simply of the _firing_ of the DragDrop event of the other DataGridView, rather than arising from any of the code in that event's sub.  You can see this by commenting out, in my original code, the whole of the code in the dgv_DragDrop sub, just leaving the signature and end

    Private Sub dgv_DragDrop(ByVal sender As Object, ByVal e As System.Windows.Forms.DragEventArgs) Handles dgvA.DragDrop, dgvB.DragDrop
        'Dim thisDGV As DataGridView = CType(sender, DataGridView)
        'Dim Source As DataGridView = e.Data.GetData("System.Windows.Forms.DataGridView", True)
        'If Source Is thisDGV Then Exit Sub

        'Dim sourceTable As DataTable = CType(Source.DataSource, DataTable)
        'Dim targetTable As DataTable = CType(thisDGV.DataSource, DataTable)

        'Dim RowsToMove As New List(Of DataRow)
        'For Each dvgr As DataGridViewRow In Source.SelectedRows
        '    RowsToMove.Add(CType(dvgr.DataBoundItem, DataRowView).Row)
        'Next
        'For Each dr As DataRow In RowsToMove
        '    Dim targetRow As DataRow = targetTable.NewRow
        '    targetRow(0) = dr(0)
        '    targetRow(1) = dr(1)
        '    targetTable.Rows.InsertAt(targetRow, 0)
        '    sourceTable.Rows.Remove(dr)
        'Next
    End Sub

If you now drag row/s from dgvA and "drop" them on dgvB nothing will happen, because the code is no longer operative.  But you will still get the phenomenon that, when you return to dgvA, you have to click twice to "activate" it.

It looks to me like a "confused focus" problem: there's some discussion of related issues in these threads

http://www.experts-exchange.com:80/Programming/Languages/C_Sharp/Q_22709068.html

and

http://www.experts-exchange.com/Programming/Languages/C_Sharp/Q_22709066.html

I am not saying there isn't a way around it but, if there is, I haven't been able to find it.  Sorry.

Roger

Thanks Roger, it's maybe something I can live with.

I'm trying to get this working in my application, but don't quite understand what's happening.
I have a book on VB2005 which I forgot to look at about the Drag & Drop, so that's clear now.

What I don't understand is what's happening with the datagridview.
How does it collect the data?

I'm having trouble knowing what code I don't need from your original code.

What I want to do, is not copy the entire row to the second dgv, but only the contents of certain fields .
For example,
in dgvA, I could have the following:
Date, Amount, AnotherDate, AnotherAmount, Total

but I want to copy only:
AnotherDate, AnotherAmount, Total
into the second dgv (also bound) - and hopefully it will handle the identity column...

As both DGVs are bound, it's best (or even necessary) to make any changes in the datasource/s.  Once those are changed, the changes are immediately reflected in the relevant DGVs.  So, whilst it LOOKS like data is being moved or copied from DGV to DGV, what is actually happening is that the DGVs are just being used as the user-interface mechanism to indicate to our code what changes need making in the datatables.

The code that actually makes the changes is in the dgv_DragDrop sub.  In the demo, it's _moving_ rows.  If, as seems to be the case, you want to _copy_ rows, then you will need to modify it a bit.  In particular, you won't want this line

            sourceTable.Rows.Remove(dr)

and - because it was the ultimate _removal_ of rows that made a separate array necessary - the code could be simplified in other ways.  But it will do no harm to leave those other bits as they are.

Only moving/copying _some_ fields is handled by this bit

        For Each dr As DataRow In RowsToMove
            Dim targetRow As DataRow = targetTable.NewRow
            targetRow(0) = dr(0)
            targetRow(1) = dr(1)
            targetTable.Rows.InsertAt(targetRow, 0)
            sourceTable.Rows.Remove(dr)
        Next

The first line within the loop creates a new row for the target datatable.  Then values - only those that we want - are copied into it from the row from the source datatable.  In the demo, one of the tables had two fields and the other three: only two were moved.  In the scenario you describe, it sounds as though you would put

            Dim targetRow As DataRow = targetTable.NewRow
            targetRow("AnotherDate") = dr("AnotherDate")
            targetRow("AnotherAmount") = dr("AnotherAmount")
            targetRow("Total") = dr("Total")
            targetTable.Rows.InsertAt(targetRow, 0)

or the relevant column numbers from the two tables (which may be different) e.g.

            targetRow(0) = dr(2)

I can't say for certain about the identity column, because I don't know the details of your data set-up.  But you might want to use

            targetTable.Rows.Add(targetRow)

rather than

            targetTable.Rows.InsertAt(targetRow, 0)

.InsertAt was used in the original demo for a specific reason, which will probably not apply in your case.  And .Add is better where indenties are being automatically assigned.

Roger

Thanks for clearing that up Roger.

Cracked it at last!
Identity column increments as expected too.

It doesn't seem to matter whether I use .Add or .InsertAt - they both work ok, but will use .Add as you suggest.

I'm really glad I re-activated my account on EE now. "Speak" to you again I'm sure...

Andrew.