ASP.NET

public DataTable GetPage(int page, int pageSize, DataTable table)
    {
        if (page < 1 || pageSize < 1)
            throw new Exception("Illegal paging values");

        if (table.Rows.Count < 1)
            throw new Exception("Invalid table");

        int fromRow = page * pageSize - pageSize;
        int toRow = fromRow + pageSize;

        DataTable dt = new DataTable();

        for (int i = fromRow; i < toRow; i++)
        {
            dt.Rows.Add(table.Rows[i]);
        }

        return dt;
    }