Drag and drop rows in a datagridview

Private fromIndex As Integer
    Private dragIndex As Integer
    Private dragRect As Rectangle

    Private Sub DataGridView1_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs) Handles DataGridView1.DragDrop
        Dim p As Point = DataGridView1.PointToClient(New Point(e.X, e.Y))
        dragIndex = DataGridView1.HitTest(p.X, p.Y).RowIndex
        If (e.Effect = DragDropEffects.Move) Then
            Dim dragRow As DataGridViewRow = CType(e.Data.GetData(GetType(DataGridViewRow)), DataGridViewRow)
            If dragIndex < 0 Then dragIndex = DataGridView1.RowCount - 1
            'If dragIndex < DataGridView1.RowCount Then dragIndex = DataGridView1.RowCount - 1
            DataGridView1.Rows.RemoveAt(fromIndex)
            DataGridView1.Rows.Insert(dragIndex, dragRow)
        End If
    End Sub

    Private Sub DataGridView1_DragOver(ByVal sender As Object,
                                   ByVal e As DragEventArgs) _
                                   Handles DataGridView1.DragOver
        e.Effect = DragDropEffects.Move
    End Sub
    Private Sub DataGridView1_MouseDown(ByVal sender As Object,
                                    ByVal e As MouseEventArgs) _
                                    Handles DataGridView1.MouseDown
        fromIndex = DataGridView1.HitTest(e.X, e.Y).RowIndex
        If fromIndex > -1 Then
            Dim dragSize As Size = SystemInformation.DragSize
            dragRect = New Rectangle(New Point(e.X - (dragSize.Width / 2),
                                       e.Y - (dragSize.Height / 2)),
                             dragSize)
        Else
            dragRect = Rectangle.Empty
        End If
    End Sub

    Private Sub DataGridView1_MouseMove(ByVal sender As Object,
                                    ByVal e As MouseEventArgs) _
                                    Handles DataGridView1.MouseMove
        If (e.Button And MouseButtons.Left) = MouseButtons.Left Then
            If (dragRect <> Rectangle.Empty _
    AndAlso Not dragRect.Contains(e.X, e.Y)) Then
                DataGridView1.DoDragDrop(DataGridView1.Rows(fromIndex),
                               DragDropEffects.Move)
            End If
        End If
    End Sub