C#•2y ago

❔ properties/constructor question

class Car
{
  public string model;
  public string color;
  public int year;

  // Create a class constructor with multiple parameters
  public Car(string modelName, string modelColor, int modelYear)
  {
    model = modelName;
    color = modelColor;
    year = modelYear;
  }

class Car
{
  public string model;
  public string color;
  public int year;

  // Create a class constructor with multiple parameters
  public Car(string modelName, string modelColor, int modelYear)
  {
    model = modelName;
    color = modelColor;
    year = modelYear;
  }

Why do we need another variable (model = modelName) ? Why cant we just set it like this

class Car
{
  public string model;
  public string color;
  public int year;

  // Create a class constructor with multiple parameters
  public Car(model, color, year)
  {
  }
}

class Car
{
  public string model;
  public string color;
  public int year;

  // Create a class constructor with multiple parameters
  public Car(model, color, year)
  {
  }
}

Sorry for such a basic question 🙏

14 Replies

Angius•2y ago

So, first things first, there are no properties in your code, just public fields And if you want something like that, you can use records Why do we need to assign the values explicitly? Well, what if you want to modify them somehow, or do some conditional logic?

♡ IV ♡OP•2y ago

oh i see, because then you would permanently alter the value instead of just for that object, right?

Angius•2y ago

Not sure what you mean

class Car
{
  public string Model { get; set; }
  public string Color { get; set; }
  public int Year { get; set; }

  // Create a class constructor with multiple parameters
  public Car(string modelName, string modelColor, int modelYear)
  {
    Model = modelName.ToUpper();
    Color = modelColor.Trim().ToUpper();
    Year = modelYear;
  }

class Car
{
  public string Model { get; set; }
  public string Color { get; set; }
  public int Year { get; set; }

  // Create a class constructor with multiple parameters
  public Car(string modelName, string modelColor, int modelYear)
  {
    Model = modelName.ToUpper();
    Color = modelColor.Trim().ToUpper();
    Year = modelYear;
  }

Here's what I mean You might want to modify the values somewhat before setting the props

♡ IV ♡OP•2y ago

Is this considered setting?

 Model = modelName.ToUpper();

 Model = modelName.ToUpper();

Angius•2y ago

Well, yeah

♡ IV ♡OP•2y ago

I also see the set; too, but just curious why we need it if we're setting the value in the constructor? Sorry ive been trying to wrap my head around this, tyvm

Angius•2y ago

It sets the Model property { get; set; } is what makes a property A default getter and a default setter They can have more code in them, of course But the idea is to put a layer on top of the class's data. The data remains private (properties generate private fields on compile time) but the accessors are public Encapsulation and all that

♡ IV ♡OP•2y ago

right right

Angius•2y ago

If you want the property to be settable just from the constructor, you can have just { get; }, no problem

♡ IV ♡OP•2y ago

Oh, wait so for this example, set; in this case is just an extra layer of protection, because we're setting the value in the constructor ?

Angius•2y ago

set; allows the value to be set even outside of the constructor, from the outside of the class

var car = new Car(..., ..., ...);
car.Color = "red"; // invokes the setter

var car = new Car(..., ..., ...);
car.Color = "red"; // invokes the setter

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

class Foo
{
    private int _bar;

    public int GetBar()
    {
        return _bar;
    }

    public void SetBar(int bar)
    {
        _bar = bar;
    }
}

can be shortened to

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

class Foo
{
    private int _bar;

    public int GetBar() => _bar;

    public void SetBar(int bar) => _bar = bar;
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get { return _bar; }
        set { _bar = value; }
    }
}

can be shortened to

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

class Foo
{
    private int _bar;
    public int Bar {
        get => _bar;
        set => _bar = value;
    }
}

can be shortened to

class Foo
{
    public int Bar { get; set; }
}

class Foo
{
    public int Bar { get; set; }
}

♡ IV ♡OP•2y ago

thank you! I also didnt know what the => meant i kept seeing so thats hepful as well. tysm!

Angius•2y ago

It's expression-bodied method The thing to the right of => has to be an expression or a one-liner statement

Accord•2y ago

Was this issue resolved? If so, run /close - otherwise I will mark this as stale and this post will be archived until there is new activity.

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❔ properties/constructor question