如何将linq查询转换为非查询表达式？

Question

我用EF6，我有这样的LINQ到实体查询：

from s in SensorObservationEntities.SensorsMeasures 
      group s by s.SensorUnitId into g 
      let latest = g.OrderByDescending(s => s.MeasureDate).FirstOrDefault() 
      select latest 

我怎么能它convet非查询表达式？

Answer 1

如果要将此转换为方法的语法版本，你能做到这一步一步来。我想先在结束并通过工作开始：

1. select到Select定义源：

   .Select(g => g.OrderByDescending(s => s.MeasureDate).FirstOrDefault()); 
   

2. group为GroupBy：

   .GroupBy(s => s.SensorUnitId) 
   .Select(g => g.OrderByDescending(s => s.MeasureDate).FirstOrDefault()); 
   

3. from的来源

   SensorObservationEntities.SensorsMeasures 
   .GroupBy(s => s.SensorUnitId) 
   .Select(g => g.OrderByDescending(s => s.MeasureDate).FirstOrDefault()); 
   

Answer 2

你的意思是方法的语法：

SensorObservationEntities.SensorsMeasures.GroupBy(g => g.SensorUnitId) 
      .Select(y => y.OrderByDescending(x => x.MeasureDate).FirstOrDefault());