C# LINQ选择每行取1

如何在linq中只返回1行的列中选择take 1。因为当我放置.Take（1）时，只会显示一行结果，但我希望有两行结果，并且具有不同的条目

我想说清楚，这就是我的意思

在c#中，这是我的疑问

using (PharmacyDBEntities entities = new PharmacyDBEntities())
        {
            var positem = (from a in entities.POSEntries.Take(1)
                          where a.Invoice.AccountID == authLogin.userid && a.Invoice.InvoiceStatusID == 1
                          select new
                          {
                              a.Item.ItemCode,
                              a.Item.Name,
                              Quantity = (from b in entities.POSEntries where b.Invoice.AccountID == authLogin.userid && b.Invoice.InvoiceStatusID == 1 select b).Count(),
                              a.Item.SellingPrice
                          }).ToList();
            gcItemList.DataSource = positem;
        }

结果呢

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有什么建议吗？会对我有很大帮助的。谢谢

Take仅返回前n个元素。我认为您需要尝试使用该方法。

那么，您想要Distinct（）而不是Take（1）？大致如下：

var positem = (from a in entities.POSEntries
    where a.Invoice.AccountID == authLogin.userid && a.Invoice.InvoiceStatusID == 1
                      select new
                      {
                          a.Item.ItemCode,
                          a.Item.Name,
                          Quantity = (from b in entities.POSEntries where b.Invoice.AccountID == authLogin.userid && b.Invoice.InvoiceStatusID == 1 select b).Count(),
                          a.Item.SellingPrice
                      }).Distinct().ToList();

---

您可以使用Linq

GroupBy

var positem = entities.POSEntries.Where( a=> a.Invoice.AccountID == authLogin.userid && a.Invoice.InvoiceStatusID == 1)
               .GroupBy(x=>x.Item.ItemCode).Select(g=> new {
                              g.Key,
                              g.First().Item.Name,
                              Quantity = g.Count(),
                              g.First().Item.SellingPrice
                          }).ToList();