//将包含1,5条件的数据筛选出来,相当于sql里的in用法:select * from 表 where user_type in (1,5) list= list.Where(a => "1,5".Contains(a.user_type)).ToList(); //此处等同于上面 list= list.Where(a => a.user_type == "1" || a.user_type == "5").ToList(); //另一种形式,...
var columnQuery = from line in strs let elements = line.Split(',') select Convert.ToInt32(elements[examNum]); // Execute the query and cache the results to improve // performance. This is helpful only with very large files. var results = columnQuery.ToList(); // Perform...
string ids = ",2,3,4,5,"; var list = context.TestTables.Where(a => ids.Contains(a.IDSearched)).ToList(); 上面语句运行时,LINQ To Entities会将其翻译为如下SQL语句: SELECT [Extent1].[RID] AS [RID], [Extent1].[NAME] AS [NAME], [Extent1].[ROWDATE] AS [ROWDATE], [Extent1]...
Array' does not contain a definition for 'Select' and no extension method 'Select' accepting a first argument of type 'System.Array' could be found (are you missing a using directive or an assembly reference?) C# Console App - Can't retrieve SOAP 1.2 response from Web Service C# Console...
您可以使用 Enumerable.ToList 或Enumerable.ToArray 方法來強制 任何 查詢立即執行。 立即執行可讓您重複使用查詢結果,而不是查詢宣告。 結果會擷取一次,然後儲存以供日後使用。 下列查詢會傳回來源陣列中偶數的計數: C# 複製 var evenNumQuery = from num in numbers where (num % 2) == 0 select num; ...
{88, 94, 65, 91}} Dim arrList As New ArrayList() arrList.Add(student1) arrList.Add(student2) arrList.Add(student3) arrList.Add(student4) ' Use an explicit type for non-generic collections Dim query = From student As Student In arrList Where student.Scores(0) >...
薪水大于17000的用户集合,投影存储他们的姓名和职业*/List<User>salary_list=salaryList.Where(u=>u.salary>17000).Select(g=>newUser(){name=g.name,occupation=g.occupation}).ToList();/*取上面两个集合的交集为结果集*/List<User>result_list=user_list.Intersect(salary_list,newCompareUser()).ToList...
List<int> numQuery2 = (fromnuminnumberswhere(num %2)==0selectnum).ToList();// or like this:// numQuery3 is still an int[]varnumQuery3 = (fromnuminnumberswhere(num %2)==0selectnum).ToArray(); 此外,还可以通过在紧跟查询表达式之后的位置放置一个foreach循环来强制执行查询。 但是,通过...
List<int> numQuery2 = (fromnuminnumberswhere(num %2)==0selectnum).ToList();// or like this:// numQuery3 is still an int[]varnumQuery3 = (fromnuminnumberswhere(num %2)==0selectnum).ToArray(); 此外,还可以通过在紧跟查询表达式之后的位置放置一个foreach循环来强制执行查询。 但是,通过...
from ccinJoinCC.DefaultIfEmpty()selectnew{CustomerName=cusetomer.name,phone=cc!=null?cc.Phone:null}; 1.2 右链接 代码语言:javascript 代码运行次数:0 运行 AI代码解释 staticList<Customer>GetCustomer()//客户{List<Customer>list=newList<Customer>();list.Add(newCustomer{id=1,name="刘德华",email="...