linq not in用法 LINQ中的"Not In"用法类似于SQL中的NOT IN。它用于筛选不包含在指定集合中的元素。 以下是使用"Not In"的简单示例: ```csharp //创建一个包含一些数字的集合 List<int> numbers = new List<int> { 1, 2, 3, 4, 5 }; //创建一个包含要排除的数字的集合 List<int> exclude...
in the FileCompare class.// The query executes immediately because it returns a bool.boolareIdentical = list1.SequenceEqual(list2, myFileCompare);if(areIdentical ==true) { Console.WriteLine("the two folders are the same"); }else{ Console.WriteLine("The two folders are not the...
(v.FullName); } var queryList2Only = (from file in list2 select file) .Except(list1, myFileCompare); Console.WriteLine(); Console.WriteLine($"The following files are in list2 but not list1 (total number = {queryList2Only.Count()}:"); foreach (var v in queryList2Only...
List<int> numbers = [ 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 ]; // The query variables can also be implicitly typed by using var // Query #1. IEnumerable<int> filteringQuery = from num in numbers where num is < 3 or > 7 select num; // Query #2. IEnumerable<int> orderingQuery...
from c in db.Customers select c.ContactName; 注意:这个语句只是一个声明或者一个描述,并没有真正把数据取出来,只有当你需要该数据的时候,它才会执行这个语句,这就是延迟加载(deferred loading)。如果,在声明的时候就返回的结果集是对象的集合。你可以使用ToList() 或ToArray()方法把查询结果先进行保存,然后再...
var czy1 = (from a in dbContext.usergl_czy join bb in dbContext.class_class on a.bm equals bb.child into bbs from b in bbs.DefaultIfEmpty() where a.czybm == "9999" select new { user = a, part = b }).ToList(); 对应的sql为: ...
For Each makeFlag In productsList Console.WriteLine(makeFlag) Next End Using 不支持引用非标量变量不支持在查询中引用非标量变量(如实体)。 在此类查询执行时,会引发 NotSupportedException 异常,并显示以下消息:“无法创建类型为‘EntityType’的常量值。 此上下文中仅支持基元类...
List<int> ages = new List<int> { 21, 46, 46, 55, 17, 21, 55, 55 }; IEnumerable<int> distinctAges = ages.Distinct(); Console.WriteLine("Distinct ages:"); foreach (int age in distinctAges) { Console.WriteLine(age); } /* This code produces the following output: Distinct ages: ...
(x=>x.Name.LocalName=="summary").Value,Href=entry.Elements().SingleOrDefault(x=>x.Name.LocalName=="link").Attribute("href").Value,Author=entry.Elements().SingleOrDefault(x=>x.Name.LocalName=="author").Elements().SingleOrDefault(x=>x.Name.LocalName=="name").Value};_list.AddRange(...
C# Linq Subquery (NOT IN) C# LINQ: How to select multiple field and return list C# Question: LINQ Select statement all records ... c# sql delete command call an oracle function from c# Can I get a value or null from an Entity query? Can I specify the parent ID column to use for...