我要评论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; }
}
}
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