C#•2w ago

Not really understanding Backing Fields with custom get; and set;

Hey all.

I'm getting a little confused with backing fields with custom getters and setters. I have the following code

  internal class Person
  {
    private string _name;
    public string Name { get { return _name; } }

    private int _age;
    public int Age
    {
      get { return _age; }
      set
      {
        if (value >= 0)
          _age = value;
        else
          Console.WriteLine("Age cannot be below 0!");        
      }
    }

    public Person(string name, int age)
    {
      _name = name;
      Age = age;
    }

    public void GreetPerson()
    {
      Console.WriteLine($"Welcome, {_name}! You're {_age} years old!");
    }
  }

  internal class Person
  {
    private string _name;
    public string Name { get { return _name; } }

    private int _age;
    public int Age
    {
      get { return _age; }
      set
      {
        if (value >= 0)
          _age = value;
        else
          Console.WriteLine("Age cannot be below 0!");        
      }
    }

    public Person(string name, int age)
    {
      _name = name;
      Age = age;
    }

    public void GreetPerson()
    {
      Console.WriteLine($"Welcome, {_name}! You're {_age} years old!");
    }
  }

  internal class Person
  {
    private string _name;
    public string Name { get { return _name; } }

    private int _age;
    public int Age
    {
      get { return _age; }
      set
      {
        if (value >= 0)
          _age = value;
        else
          Console.WriteLine("Age cannot be below 0!");        
      }
    }

    public Person(string name, int age)
    {
      _name = name;
      Age = age;
    }

    public void GreetPerson()
    {
      Console.WriteLine($"Welcome, {_name}! You're {_age} years old!");
    }
  }

  internal class Person
  {
    private string _name;
    public string Name { get { return _name; } }

    private int _age;
    public int Age
    {
      get { return _age; }
      set
      {
        if (value >= 0)
          _age = value;
        else
          Console.WriteLine("Age cannot be below 0!");        
      }
    }

    public Person(string name, int age)
    {
      _name = name;
      Age = age;
    }

    public void GreetPerson()
    {
      Console.WriteLine($"Welcome, {_name}! You're {_age} years old!");
    }
  }

The thing that's confusing me is, how they're assigned within the constructor. I'll try to explain as best as I can.

If in the constructor,

_name = name

_name = name

_name = name

_name = name, which is using the backing field (I assume), how come for the age I need to do

Age = age

Age = age

Age = age

Age = age and not

_age = age

_age = age

_age = age

_age = age?, it feels like

_age

_age

_age

_age isn't being used at all.

Is it because of how

_age

_age

_age

_age is used in the

set

set

set

set why

Age

Age

Age

Age is used in the constructor?
For example; if 5 is used on initialization of the object, the setter is setting _age to 5, then as we're getting

_age

_age

_age

_age via

Age

Age

Age

Age, this is why

Age

Age

Age

Age is used in the constructor and not

_age

_age

_age

_age? I hope that's correct!

Sorry if I've explained this poorly...

テ

ティナ•12/8/25, 1:33 PM

you perform a check if you set

_age

_age

through

Age

Age

you can treat

private int _b;
public int B{ set{ _b=value; } }

private int _b;
public int B{ set{ _b=value; } }

private int _b;
public void SetB(int value){
  _b=value;
}

private int _b;
public void SetB(int value){
  _b=value;
}

Captain Kernel•12/8/25, 2:53 PM

Also NameName has no setter so you can only set it directly, whereas

Age

Age

does have a setter and that's intended to prevent illegal values being stored in

_age

_age

. The field

_age

_age

is used but only by the

Age

Age

property, anything that touches the

Age

Age

property indirectly also touches

_age

_age

Kuurama•12/8/25, 11:46 PM

And if you don't wanna use _age by mistake, lookup the "C# 14 field keyword".

It might solve some programming messup.

Not really understanding Backing Fields with custom get; and set;

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