小编Kar*_*hik的帖子

案例1: 我在两个上下文中通过ToList()方法加入了两个不同的DB Context.

案例2: 并尝试加入第一个Db Context ToList()和第二个AsQueryable().

两者都适合我.我想知道的是那些关于性能和功能的加入之间的区别.哪一个更好 ？

var users = (from usr in dbContext.User.AsNoTracking()
                  select new
                  {
                     usr.UserId,
                     usr.UserName
                  }).ToList();

 var logInfo= (from log in dbContext1.LogInfo.AsNoTracking()
               select new
               {
                   log.UserId,
                   log.LogInformation
               }).AsQueryable();

 var finalQuery= (from usr in users
                  join log in logInfo on usr.UserId equals log.UserId
                  select new
                  {
                     usr.UserName,
                     log.LogInformation
                  }.ToList();

这是我用过的LINQ查询

var result = (from price in inventoryDb.Pricing.AsNoTracking()               
              where price.Quantity > 0m
              select new
              {
                 TagNo = price.TagNo,
                 SellingRate = price.SellingRate,
                 Quantity = price.Quantity           
              }).ToList();

基于Quantity我需要在列表中生成重复项的值.

输出:

result = [0]{TagNo="100", SellingRate=1500.00, Quantity=1}
         [1]{TagNo="101", SellingRate=1600.00, Quantity=2}

预期结果:

result = [0]{TagNo="100", SellingRate=1500.00}
         [1]{TagNo="101", SellingRate=1600.00}
         [2]{TagNo="101", SellingRate=1600.00}