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屬性我真是一個初學者,遇到過這個問題,我解決不了甚至花小時後搜索互聯網。我不明白爲什麼堆棧對象Grades始終爲空,每次運行應用程序時,都會拋出「System.NullReferenceException」異常。當我將鼠標懸停在我的鼠標上檔次,它說:「場‘Student.Grades’從未分配,將永遠有它的默認值空」。我也不能使用「{get; set;}」來訪問這個屬性。那麼誰能告訴我爲什麼?非常感謝!(第一次要求對堆棧溢出問題,遺憾的壞格式)C#不能建立一個堆棧<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++;
}
}