private void gridView1_PrintInitialize(object sender, DevExpress.XtraGrid.Views.Base.PrintInitializeEventArgs e) {
  PrintingSystemBase pb = e.PrintingSystem as PrintingSystemBase;
  pb.PageSettings.PaperKind = System.Drawing.Printing.PaperKind.Legal;
  pb.PageSettings.Landscape = true;
}

private void preview(GridControl grid) {
  if (!grid.IsPrintingAvailable) {
    MessageBox.Show("The 'XtraPrinting' library is not found", "Error");
    return;
  }
  grid.ShowRibbonPrintPreview();
}

private void btnPrint_Click(object sender, EventArgs e) {
  preview(dtMembers);
}