Csharp/CSharp Tutorial/struct/Box Unbox

Box and unbox a struct

<source lang="csharp">using System; struct EMPLOYEE {

 public string name;
 public short deptID;
 public EMPLOYEE(string n, short d)
 {
   name = n;
   deptID = d;
 }

} class MainClass {

 public static void Main(string[] args) {
   EMPLOYEE fred = new EMPLOYEE("s",1);
   fred.name = "F";
   object stanInBox = fred;
 
   UnboxThisEmployee(stanInBox);
 }
 public static void UnboxThisEmployee(object o)
 {
   EMPLOYEE temp = (EMPLOYEE)o;
   Console.WriteLine(temp.name);
 }
 

}</source>

F

Box a struct, change its value and unbox it

<source lang="csharp">public interface IModifyMyStruct {

  int X
  {
     get;
     set;
  }

} public struct MyStruct : IModifyMyStruct {

  public int x;
  public int X
  {
     get
     {
        return x;
     }
     set
     {
        x = value;
     }
  }
  public override string ToString()
  {
     return x.ToString();
  }

} public class MainClass {

  static void Main()
  {
     MyStruct myval = new MyStruct();
     myval.x = 123;
     object obj = myval;
     System.Console.WriteLine( "{0}", obj.ToString() );
     IModifyMyStruct iface = (IModifyMyStruct) obj;
     iface.X = 456;
     System.Console.WriteLine( "{0}", obj.ToString() );
     MyStruct newval = (MyStruct) obj;
     System.Console.WriteLine( "{0}", newval.ToString() );
  }

}</source>

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456

Box struct to call its implemented interface

<source lang="csharp">public interface IDisplay {

  void Print();

} public struct MyStruct : IDisplay {

  public int x;
  public void Print()
  {
     System.Console.WriteLine( "{0}", x );
  }

} public class MainClass {

  static void Main()
  {
     MyStruct myval = new MyStruct();
     myval.x = 123;
     // no boxing
     myval.Print();
     // must box the value
     IDisplay printer = myval;
     printer.Print();
  }

}</source>

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