我遇到了一些 linq 编译查询的性能问题。
using (var txn = new TransactionScope(TransactionScopeOption.Required, new TransactionOptions { IsolationLevel = System.Transactions.IsolationLevel.ReadUncommitted }))
{
DateTime dealcheck = new DateTime(1753, 2, 2);
Func<DealDataClassesDataContext, string, IQueryable<DealsDetails>> DD =
CompiledQuery.Compile<DealDataClassesDataContext, string, IQueryable<DealsDetails>>
((DealDataClassesDataContext nw, string sCity) =>
from D in nw.Deals
where D.Address == City && (D.DealTime >= DateTime.Now || D.DealTime == dealcheck) && PriceMax >= D.DealPrice && D.DealPrice >= PriceMin && DisCountMax >= D.SavingsRate && D.SavingsRate >= DiscountMin && (D.DealTime >= DateTime.Now.AddDays(TimeMin) && D.DealTime <= DateTime.Now.AddDays(TimeMax) || D.DealTime == dealcheck)
select new DealsDetails(
lst,
D.DealId,
D.DealHeadline,
D.DealCategory,
D.BuyPrice,
D.DealPrice,
D.SavingsRate,
D.SavingAmount,
D.RelatedWebsite,
D.Address,
string.Empty,
D.DealImage,
string.Empty,
string.Empty,
D.Time, D.CurrentTime, D.DealTime,
D.Location, string.Empty, string.Empty, D.Latitude, D.Longitude, D.Islocal, D.VendorMail, D.MerchantInfo, D.Review, D.HowItWork, D.DealUrl
));
string jString = "";
//int a = q(DealDbContext1, "London").Count();
using (DealDataClassesDataContext db = new DealDataClassesDataContext())
{
IQueryable<DealsDetails> DDD = DD.Invoke(DealDbContext, "London");
if (lstSite.Count > 0 && lstSite[0] != "AllDeals")
{
DDD = DDD.Where(D => D.RelatedWebsite.Split(',').Where(x => lstSite.Contains(x)).Any()); //.Where(row => row.Category.ToList().Where(x => lst.Contains(x)).Any()).ToList();
}
if (lst.Count > 0)
{
DDD = DDD.Where(D => D.Categories.Split(',').Where(x => lst.Contains(x)).Any()); //.Where(row => row.Category.ToList().Where(x => lst.Contains(x)).Any()).ToList();
}
if (sortby == "Time" && orderby == "Asc")
{
DDD = (from d in DDD orderby d.Time ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else if (sortby == "Time" && orderby == "Desc")
{
DDD = (from d in DDD orderby d.Time descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else if (sortby == "Price" && orderby == "Asc")
{
DDD = (from d in DDD orderby d.DealPrice ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else if (sortby == "Price" && orderby == "Desc")
{
DDD = (from d in DDD orderby d.DealPrice descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else if (sortby == "Percent" && orderby == "Asc")
{
DDD = (from d in DDD orderby d.SavingsRate ascending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else if (sortby == "Percent" && orderby == "Desc")
{
DDD = (from d in DDD orderby d.SavingsRate descending select d).Skip((Page - 1) * PageSize).Take(PageSize);
}
else
{
DDD = DDD.Skip((Page - 1) * PageSize).Take(PageSize);
}
string Currency = "$";
foreach (DealsDetails item in DDD)
{
//Creating Html String Here
}
return jString;
我在这里附上了我的整个代码，请检查这是什么问题，它需要很长时间才能响应 20 秒左右。
主要是 foreach 循环耗时超过 17 秒。
请让我知道如何编译此查询。
提前致谢。