C# 判斷list類型中某字段是否存在相同值

新建model

public class Student

{

    public int ID { get; set; }

    public string Name { get; set; }

    public string  Class  {get; set; }  

}

新建list

List<Student> stu = new List<Student>();

判斷name是否重復 /////// 判斷name與class是否都重復

bool isRepeat = stu.GroupBy(i => i.Name).Any(g => g.Count() > 1);

bool isRepeat = stu.GroupBy(i => new { m.Name, m.Class}).Any(g => g.Count() > 1);

isRepeat 為true 存在重復，false 不存在