public string LogSring()
{
int buynum = SessionOrders.Count(a => a.type == "buy");
int sellnum = SessionOrders.Count(a => a.type == "sell");
var list = SessionOrders.OrderByDescending(a => a.price);
StringBuilder sb_orders = new StringBuilder();
sb_orders.AppendLine();
foreach (var item in list)
{
sb_orders.AppendLine(string.Format("{0} Price:{1}，Amount:{2}，ID:{3}", item.type == "buy" ? "+B" : "-S", item.price, item.amount, item.order_id));
}
return($"Buy Count:{buynum}，Sell Count:{sellnum}. {sb_orders.ToString()}");
}
