Linq操作ArrayList
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2023-11-13 16:50:10
ArrayList实现了System.Collections空间下的IEnumerable接口,这个接口是非泛型的。如果要使用LINQ,必须声明枚举变量的类型,依赖Cast查询运算符转换枚举类型。 using System; using System.Collections; using Syste ......
arraylist实现了system.collections空间下的ienumerable接口,这个接口是非泛型的。如果要使用linq,必须声明枚举变量的类型,依赖cast查询运算符转换枚举类型。
using system; using system.collections; using system.collections.generic; using system.data; using system.io; using system.linq; namespace consoleapp4 { class program { static void main(string[] args) { var arraylist = getarraylist(); //查询表达式 var query = from student student in arraylist where student.scores[0] > 95 select student; //方法调用 var query2 = arraylist.cast<student>().where(x => x.scores[0] > 95); } static arraylist getarraylist() { arraylist arrlist = new arraylist { new student { firstname = "svetlana", lastname = "omelchenko", scores = new int[] { 98, 92, 81, 60 } }, new student { firstname = "claire", lastname = "o’donnell", scores = new int[] { 75, 84, 91, 39 } }, new student { firstname = "claire", lastname = "o’donnell", scores = new int[] { 75, 84, 91, 39 } },new student { firstname = "cesar", lastname = "garcia", scores = new int[] { 97, 89, 85, 82 } }}; return arrlist; } } public class student { public string firstname { get; set; } public string lastname { get; set; } public int[] scores { get; set; } } }