在c＃中通过linq查询查找记录 [英] Find a record through linq query in c#

问题描述

亲爱的朋友，这些是我的实体

Dear friend these are my entities

public class FileInformation : Entity
        {            
            
            public string FileName { get; set; }            
            public string FilePath { get; set; }            
            public string Clientid { get; set; }
            public List<ChangeInformation> ChangeInformations { get; set; }
            public FileInformation()
            {
                this.ChangeInformations = new List<ChangeInformation>();
            }
        }
        public class ChangeInformation 
        {
                        
            public string FileName { get; set; }            
            public string OldFileName { get; set; }            
            public long FileSize { get; set; }            
            public DateTime ModifiedDate { get; set; }            
            public string HashValue { get; set; }
            public string DeviceID { get; set; }            
            public DateTime CreationDate { get; set; }            
            public string Status { get; set; }
            public ChangeInformation()
            {

            }
        } 

< br $> b $ b

如何找到所有删除了更改信息状态的文件？



什么我试过了：



i试过以下查询

var files = finfo.Where（n => n.ChangeInformations .Where（x => x.Status ==Deleted）;

how i can find all the files whose status in change information are deleted ?

What I have tried:

i have tried following query
var files = finfo.Where(n => n.ChangeInformations.Where(x=>x.Status=="Deleted");

推荐答案

Where子句是 Func< tinput，bool> 。这意味着返回必须是布尔值。 n.ChangeInformations.Where（x => x.Status ==Deleted）如果任何项符合条件，则应使用Any返回布尔值：

A Where clause is Func<tinput,bool>. That means that the return must be a boolean. n.ChangeInformations.Where(x=>x.Status=="Deleted") is not a boolean. You should use Any which will return a boolean if any items match the criteria:

var files = finfo.Where(n => n.ChangeInformations.Any(x=>x.Status=="Deleted"));

这个地方告诉你这是怎么做的



C＃中的101个LINQ样本 [ ^ ]

This place show you how do this

101 LINQ Samples in C#[^]

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