Pass the link via vs pass reference by value - C #

Question

Hi,

I get the difference between passing by value and passing by reference. But passing the link (e.g. an array) by ref and passing the array by value is something that I cannot understand. How can you pass a link by link?

     int[] myArray = {1,2,3};
     PassByVal(myArray);
     PassByRef(ref myArray);

     PassByVal(int[] array)
     {    array = new int[] {7,8,9};   // will not work }

     PassByRef(ref int[] array)
     {    array = new int[] {10,11,12}; }  // will work

Answer 1

I suggest you check this link . It is quite useful and contains very simple examples of passing parameters in C # .

, - . , , , . ref - , , - . , :

void Foo (ref StringBuilder x) {
    x = null;
}

...

StringBuilder y = new StringBuilder();
y.Append ("hello");
Foo (ref y);
Console.WriteLine (y==null); // will write TRUE

---

int[] myArray = {1,2,3};
PassByVal(myArray);
PassByRef(ref myArray);

PassByVal(int[] array){
    // the function copy the value of the pointer in a new location of memory
    // the "copied" pointer still points to the array 123    

    // now you are modifying the object pointed by THE COPY of the pointer
    // the original pointer still points to array 123
    // the copy of the pointer will point to array 456
    array = new int[] {7,8,9}; 

} // will not work

PassByRef(ref int[] array){
   // here you are passing the pointer without creating a copy of it in a 
   // new location of memory

   // we have not a original pointer and a "copyed" pointer
   // we have only the original pointer and now whe point it to array 10,11,12
   array = new int[] {10,11,12}; 
}  // will work

Answer 2

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:

void RefByRef(ref object x)
{
  x=new object(2);
}

void RefByValue(object x)
{
 x=new object(2);//Only changes a local variable and gets discarded once the function exits
}

void Test()
{
  object x1=1;
  object x1a=x1;
  RefByRef(ref x1);
  //x1 is now a boxed 2
  //x1a is still a boxed 1


  object x2=1;
  RefByValue(x2);
  //x2 is still a boxed 1
}

Answer 3

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int = 10;

int j = i;

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o = 10;

p = o;

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int i = 10;
SomeMethod(i);
Console.WriteLine(i);

static void SomeMethod(int value)
{
  value = 20;
}

SomeMethod, . , i. 10:

;

  class Program
  {
    static void Main(string[] args)
    {
      Customer c = new Customer() { Name = "Mike" };
      SomeMethod(c);
      Console.WriteLine(c.Name);
    }

    static void SomeMethod(Customer customer)
    {
      customer.Name = "John";
    }
  }

  class Customer
  {
    public string Name { get; set; }
  }

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  class Program
  {
    static void Main(string[] args)
    {
      Customer c = new Customer() { Name = "Mike" };
      SomeMethod(c);
      Console.WriteLine(c.Name);
    }

    static void SomeMethod(Customer customer)
    {
      customer = new Customer();
      customer.Name = "John";
    }
  }

  class Customer
  {
    public string Name { get; set; }
  }

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  class Program
  {
    static void Main(string[] args)
    {
      Customer c = new Customer() { Name = "Mike" };
      SomeMethod(ref c);
      Console.WriteLine(c.Name);
    }

    static void SomeMethod(ref Customer customer)
    {
      customer = new Customer();
      customer.Name = "John";
    }
  }

  class Customer
  {
    public string Name { get; set; }
  }

Answer 4

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