如何转换通用列表<匿名类型>到通用列表< Classname&gt ;? [英] How to convert Generic List<anonymous type > to Generic List <Classname>?

问题描述

我有一个数据库，每'n'秒插入一次CPU使用率，我的任务是从数据库中获取最新的CPU条目.我想显示数据库tat中属于特定服务器的最新CPU条目，并将结果保存到通用列表中.

I have a database, where the CPU usage is inserted for every 'n' seconds and my task is to get the latest CPU entry from the database. I would like to display the latest CPU entry from the database tat belongs to the particular server , and I would like to save the result into a generic list.

我尝试过的，

    string match = "ServerX"

    List<UsageCPU> cpus = (from a in db.UsageCPUs
                          where a.ServerID.Contains(match)
                          group a by a.ServerID into b
                          orderby b.Key
                          select new { ServerID = b.Key, 
                          Usage = b.FirstOrDefault() }).ToList();

，我想遍历结果cpus以执行其他步骤.

and I would like to loop through the result cpus to perform further other steps.

但出现以下错误

无法隐式转换类型 'System.Collections.Generic.List< AnonymousType#1>' "System.Collections.Generic.List< FNC_RAQIT_HM_UI.UsageCPU>".

Cannot implicitly convert type 'System.Collections.Generic.List<AnonymousType#1>' to 'System.Collections.Generic.List<FNC_RAQIT_HM_UI.UsageCPU>'.

编辑

更新 来自Satpal的以下查询对我有用..但是使用var

UPDATE The following query from Satpal worked for me.. but using var

   var cpus = (from a in db.UsageCPUs
                    where a.ServerID.Contains(match)
                    group a by a.ServerID into b
                    orderby b.Key
                    select new
                    {
                        ServerID = b.Key,
                        Usage = b.FirstOrDefault().Usage
                    }).ToList();

        foreach (var item in cpus)
        {
           if(bla bla..)
        }

请帮忙！

推荐答案

使用

List<UsageCPU> cpus = (from a in db.UsageCPUs
                      where a.ServerID.Contains(match)
                      group a by a.ServerID into b
                      orderby b.Key
                      select new UsageCPU  //Added UsageCPU  
                      { 
                          ServerID = b.Key, 
                          Usage = b.FirstOrDefault().Usage 
                      }).ToList();

根据错误更新

无法在LINQ to Entities查询中构造实体

The entity cannot be constructed in a LINQ to Entities query

List<UsageCPU> cpus = (from a in db.UsageCPUs
                      where a.ServerID.Contains(match)
                      group a by a.ServerID into b
                      orderby b.Key
                      select new 
                      { 
                          ServerID = b.Key, 
                          Usage = b.FirstOrDefault().Usage
                      })
                    .AsEnumerable()
                    .Select(x => new UsageCPU  
                    {
                       ServerID ,
                       Usage            
                    }).ToList();

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