[RESOLVED] DataGridView cancel new row addition and move to last row of grid

[Mark@SF]

I have been struggling with two DataGridView issues. My DataGridView is bound to a DataTable via a BindingSource.

The first issue that I am having trouble with is moving the selected cell after I cancel an edit. I am trying to do this at the end of the below code listing ("If flgCancel Then..."). What happens is the highlighted cell remains at the row/column of the cell with the cancelled edit.

I use the CellValidating event of the DataGridView as follows:

    Private Sub dgvActions_CellValidating(ByVal sender As Object, ByVal e As System.Windows.Forms.DataGridViewCellValidatingEventArgs) Handles dgvActions.CellValidating

        'https://msdn.microsoft.com/en-us/library/ykdxa0bc.aspx#Y400
        'http://stackoverflow.com/questions/20756463/restoring-previous-cell-value-in-c-sharp-data

        'dgvActions.CancelEdit() '...clear any errors associated with the cell
        'dgvActions.EndEdit()    '...the MSDN documentation is incorrect and the public overload of CancelEdit does not exit edit mode and to do so we need to follow it with EndEdit

        'https://social.msdn.microsoft.com/Forums/en-US/84c06fbe-5c55-42b0-bc2d-6096c2720b4d/datagridviewcanceledit-doesnt?forum=winformsdatacontrols

        Dim strMethodName = New System.Diagnostics.StackTrace().GetFrame(0).GetMethod().Name    '...this procedure's name

        Dim flgDebug As Boolean = False   '...debug/test purposes only
        Dim flgCancel As Boolean = False

        Try
            If dgvActions.Columns(e.ColumnIndex).Name = "ActionName" Then
                If String.IsNullOrEmpty(e.FormattedValue.ToString()) Then
                    If MessageBox.Show("Action cannot not be blank, empty, or a zero-length string (ZLS)." & vbCrLf & vbCrLf & _
                                    "Cancel edits or retry editing?", "Action", MessageBoxButtons.RetryCancel, MessageBoxIcon.Warning) = Windows.Forms.DialogResult.Cancel Then
                        flgCancel = True
                    Else
                        e.Cancel = True
                        dgvActions.CurrentRow.Cells("ActionName").Selected = True
                        If Not IsNothing(dgvActions.Rows(e.RowIndex).Cells("ActionName").Tag) Then
                            dgvActions.Rows(e.RowIndex).Cells("ActionName").Value = dgvActions.Rows(e.RowIndex).Cells("ActionName").Tag
                        End If
                    End If
                End If

            ElseIf dgvActions.Columns(e.ColumnIndex).Name = "FinishDate" Then
                If e.FormattedValue.ToString() <> "" Then
                    If Not IsDate(e.FormattedValue.ToString()) Then
                        If MessageBox.Show("Finish date is not a valid date." & vbCrLf & vbCrLf & _
                                    "Cancel edits or retry editing?", "Action", MessageBoxButtons.RetryCancel, MessageBoxIcon.Warning) = Windows.Forms.DialogResult.Cancel Then
                            flgCancel = True
                        Else
                            e.Cancel = True
                            dgvActions.CurrentRow.Cells("FinishDate").Selected = True
                            If Not IsNothing(dgvActions.Rows(e.RowIndex).Cells("FinishDate").Tag) Then
                                dgvActions.Rows(e.RowIndex).Cells("FinishDate").Value = dgvActions.Rows(e.RowIndex).Cells("FinishDate").Tag
                            End If
                        End If
                    End If
                End If
            End If

            If flgCancel Then
                Dim priorRowIndex As Integer = e.RowIndex - 1
                dgvActions.CancelEdit() '...clear any errors associated with the cell
                dgvActions.EndEdit()    '...the MSDN documentation is incorrect and the public overload of CancelEdit does not exit edit mode and to do so we need to follow it with EndEdit
                dgvActions.Rows(priorRowIndex).Cells(e.ColumnIndex).Selected = True
                bsActions.Position = priorRowIndex
                _FormDirty = IsBindingSourceDirty(bsActions)
                btnSave.Enabled = _FormDirty
                btnCancel.Enabled = _FormDirty
            End If

        Catch ex As Exception
            MessageBox.Show(ex.GetType.ToString & vbCrLf & vbCrLf & ex.Message & " (err=" & Err.Number & ")", strMethodName, MessageBoxButtons.OK, MessageBoxIcon.Error)

        End Try

    End Sub

The second issue that I'm having trouble figuring out is when cancelling an edit to a new row in the grid, the above code does not move up to the last existing row in the grid, and then the BindingSource.AddingNew event fires. What I want to do when cancelling the edits to a new row is put the focus back on an existing row and stop trying to add any more new rows. How do I prevent the AddingNew event from firing in this scenario?

What should I do to make this happen? Appreciate any advice...thanks!

[jmcilhinney]

I haven't read all that code but I suspect that some of it at least doesn't belong in the CellValidating event handler. The purpose of that event is to allow you to validate the contents of the cell that the user is trying to leave. If you're doing anything beyond that then you're misusing the event. You are supposed to test the contents of the cell and set e.Cancel to True if it's not valid, which will prevent the cell losing focus. That's it, that's all. If you want to do anything more than that then you should look at the CellValidated and/or CellLeave events.

[Mark@SF]

Thank you, JMC. Appreciate all your help!