// print two grids into an existing PrintDocument
private void button1_Click(object sender, EventArgs e)
{
  using (var dlg = new PrintPreviewDialog())
  {
    dlg.Document = this.printDocument1;
    dlg.ShowDialog(this);
  }
}
// event handlers for the PrintDocument object on the form
PrintDocumentGridRenderer _g1, _g2;
void printDocument1_BeginPrint(object sender, System.Drawing.Printing.PrintEventArgs e)
{
// create and configure grid renderer for the first grid
_g1 = new PrintDocumentGridRenderer(c1FlexGrid1);
_g1.Options = PrintGridFlags.FitToPageWidth | PrintGridFlags.ExtendLastCol;
// create and configure grid renderer for the second grid
_g2 = new PrintDocumentGridRenderer(c1FlexGrid2);
_g2.Options = PrintGridFlags.FitToPageWidth | PrintGridFlags.ExtendLastCol;
}
void printDocument1_PrintPage(object sender, System.Drawing.Printing.PrintPageEventArgs e)
{
// render first grid
if (_g1.CurrentPage < _g1.PageCount)
{
_g1.PrintPage(e);
e.HasMorePages = true;
}
// render second grid
else if (_g2.CurrentPage < _g2.PageCount)
{
_g2.PrintPage(e);
e.HasMorePages = _g2.CurrentPage < _g2.PageCount;
}
}