引用類型對象沒有得到更新，但返回更新的對象

Question

我正在將「引用類型」傳遞給函數「BY VAL」。在函數中，我試圖修改foreach循環中的引用類型。

然後當涉及到調用者，我通過的對象 沒有得到更新。 但返回更新的對象。

我給出了下面這個問題的例子。

有人可以幫助我，爲什麼它會發生這樣的花費幾分鐘嗎？

下面是方法GetStudents（），FilterStudents（）， 班，學生，老師，SSCClass，

SSCClass - 包含教師陣列。 老師 - 包含學生數組。

public void GetStudents() 
    { 

     Student[] sscStudentsOne = new Student[] { new Student { V_SId = 1, V_SName = "Kumar" }, new Student { V_SId = 2, V_SName = "Varun" }, new Student { V_SId = 3, V_SName = "Murthy" } }; 

     Student[] sscStudentsTwo = new Student[] { new Student { V_SId = 4, V_SName = "Sathya" }, new Student { V_SId = 5, V_SName = "Krishna" }, new Student { V_SId = 6, V_SName = "Bindu" } }; 


     Teacher[] sscTeachers = new Teacher[] { new Teacher { V_tId = 1, V_tName = "Jyothi", V_Students = sscStudentsOne }, new Teacher { V_tId = 2, V_tName = "Srinivas", V_Students = sscStudentsTwo } }; 

     SSCClass objSSCClass = new SSCClass(); 
     objSSCClass.V_sscTeachers = sscTeachers; 

     SSCClass objSSCClassFiltered = FilterStudents(objSSCClass); 
     // Problem :- 
     // in objSSCClass Kumar is getting removed but Sathya from second teachere is not getting removed. 
     // in objSSCClassFiltered Kumar and Sathya are Getting removed as we did. 
     // We need objSSCClass object to be updated successfully .. as we can not return this to caller method in my project. 

    } 
    public SSCClass FilterStudents(SSCClass objSSCClasstobeFiltered) 
    { 

     foreach (Teacher item in objSSCClasstobeFiltered.V_sscTeachers) 
     { 

      // here a method will be called and does the below 
      // removes Students based on some criteria 
      // Say, 
      // Remove Student Kumar from first teacher. 
      // Remove Student Sathya from second teacher 

     } 

     // after filtering Students return the SSC Class object 

     return objSSCClasstobeFiltered; 
    } 

    public class Student 
    { 

     int v_sId; 

     public int V_SId 
     { 
      get { return v_sId; } 
      set { v_sId = value; } 
     } 

     string v_SName; 

     public string V_SName 
     { 
      get { return v_SName; } 
      set { v_SName = value; } 
     } 
    } 

    public class Teacher 
    { 

     int v_tId; 

     public int V_tId 
     { 
      get { return v_tId; } 
      set { v_tId = value; } 
     } 


     string v_tName; 

     public string V_tName 
     { 
      get { return v_tName; } 
      set { v_tName = value; } 
     } 


     Student[] v_Students; 

     public Student[] V_Students 
     { 
      get { return v_Students; } 
      set { v_Students = value; } 
     } 
    } 


    public class SSCClass 
    { 
     Teacher[] v_sscTeachers; 

     public Teacher[] V_sscTeachers 
     { 
      get { return v_sscTeachers; } 
      set { v_sscTeachers = value; } 
     } 

    } 

Answer 1

無法更新Foreach參考，使一個新的，然後更新它：

與您遇到麻煩，因爲我自己

Foreach (Student s in student_list) 
{... 
    S s2 = s; 
    s2 = newval; 
...}