PageBreak Property (XLRow)
Gets or sets whether there will be a forced page break after this row.
The code below inserts forced page breaks at every 10th row on a sheet, and clears the breaks at all other rows.
C1.C1Excel.XLSheet sheet = c1XLBook1.Sheets[0];
for (int r = 0; r < sheet.Rows.Count; r++)
{
sheet.Rows[r].PageBreak = (r > 0 && r % 10 == 0);
}