LINQ为了通过聚集在选择{}

本文介绍了LINQ为了通过聚集在选择{}的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

这里有一个我的工作：

var fStep = from insp in sq.Inspections where insp.TestTimeStamp > dStartTime && insp.TestTimeStamp < dEndTime && insp.Model == "EP" && insp.TestResults != "P" group insp by new { insp.TestResults, insp.FailStep } into grp select new { FailedCount = (grp.Key.TestResults == "F" ? grp.Count() : 0), CancelCount = (grp.Key.TestResults == "C" ? grp.Count() : 0), grp.Key.TestResults, grp.Key.FailStep, PercentFailed = Convert.ToDecimal(1.0 * grp.Count() /tcount*100) } ;

我想排序依据在选择投影领域的一个或多个。

I would like to orderby one or more of the fields in the select projection.

推荐答案

最简单的变化可能是使用查询延续：

The simplest change is probably to use a query continuation:

var fStep = from insp in sq.Inspections where insp.TestTimeStamp > dStartTime && insp.TestTimeStamp < dEndTime && insp.Model == "EP" && insp.TestResults != "P" group insp by new { insp.TestResults, insp.FailStep } into grp select new { FailedCount = (grp.Key.TestResults == "F" ? grp.Count() : 0), CancelCount = (grp.Key.TestResults == "C" ? grp.Count() : 0), grp.Key.TestResults, grp.Key.FailStep, PercentFailed = Convert.ToDecimal(1.0 * grp.Count() /tcount*100) } into selection orderby selection.FailedCount, selection.CancelCount select selection;

这主要是相当于用让，说实话 - 真正的区别是，让引入了的新的的范围变量，而查询延续有效地启动一系列变量的新天地 - 你不能后参考 GRP 位在进入选择例如

That's mostly equivalent to using "let", to be honest - the real difference is that let introduces a new range variable, whereas a query continuation effectively starts a new scope of range variables - you couldn't refer to grp within the bit after into selection for example.

这是值得注意的是，这是的究竟的一样使用两个语句：

It's worth noting that this is exactly the same as using two statements:

var unordered = from insp in sq.Inspections where insp.TestTimeStamp > dStartTime && insp.TestTimeStamp < dEndTime && insp.Model == "EP" && insp.TestResults != "P" group insp by new { insp.TestResults, insp.FailStep } into grp select new { FailedCount = (grp.Key.TestResults == "F" ? grp.Count() : 0), CancelCount = (grp.Key.TestResults == "C" ? grp.Count() : 0), grp.Key.TestResults, grp.Key.FailStep, PercentFailed = Convert.ToDecimal(1.0 * grp.Count() /tcount*100) }; var fStep = from selection in unordered orderby selection.FailedCount, selection.CancelCount select selection;