Private Sub DGV_DragDrop(ByVal sender As Object, ByVal e As DragEventArgs)
 
    Dim ptc As Point = DGV.PointToClient(New Point(e.X, e.Y))
    Dim index As Int32 = DGV.HitTest(ptc.X, ptc.Y).RowIndex
    If e.Effect = DragDropEffects.Move Then
        Dim RowToMove As DataGridViewRow = DirectCast(e.Data.GetData(GetType( _
          DataGridViewRow)), DataGridViewRow)
        DGV.Rows.RemoveAt(mdrIndex)
        DGV.Rows.Insert(index, RowToMove)
        DGV.Rows(index).Selected = True
    End If
 
    For i As Integer = 0 To DGV.Rows.Count - 1
        If i <> index Then
            DGV.Rows.Selected = False
        End If
    Next
 
End Sub

Gruß
Christoph