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类
属性我真是一个初学者,遇到过这个问题,我解决不了甚至花小时后搜索互联网。我不明白为什么堆栈对象Grades始终为空,每次运行应用程序时,都会抛出“System.NullReferenceException”异常。当我将鼠标悬停在我的鼠标上档次,它说:“场‘Student.Grades’从未分配,将永远有它的默认值空”。我也不能使用“{get; set;}”来访问这个属性。那么谁能告诉我为什么?非常感谢!(第一次要求对堆栈溢出问题,遗憾的坏格式)C#不能建立一个堆栈<T>在C#中
class Student : Person
{
public int studentID { get; set; }
public static int nextID;
public Stack<int> Grades;
public Student(string firstName, string lastName, DateTime birthDate,
string address1, string address2, string city, string state,
string zip, string country)
{
FirstName = firstName;
LastName = lastName;
BirthDate = birthDate;
Address1 = address1;
Address2 = address2;
City = city;
State = state;
Zip = zip;
Country = country;
//track the number of students enrolled
studentID = nextID;
nextID++;
}
}