CODEWITHSUNDEEP
c#inheritance
N0xus
N0xus

Reputation: 2724

Inheritance constructor issue

I'm having a slight issue with some inheritance.

In my base class I have the following constructor: 

    public Camera(string n)
    {
         name = n;
    }

Then in my child class I have the following constructor:

   public StereoCameras(string n) 
    {
        name = n;

    }

How ever, my child class complains it does not contain a constructor that takes 0 arguments. I'm fairly new to using inheritance like this, and I thought I had set up my childs constructor properly.

Is there something I'm missing?

Upvotes: 1

Views: 152

Answers (5)

anupama.kp
anupama.kp

Reputation: 56

Just add a constructor without any parameter to the base class. This will solve your issue.

    public Camera()
    {

    }

Upvotes: 0

Habib
Habib

Reputation: 223267

Your child class constructor call is equivalent to:

public StereoCameras(string n) : base()

since you have not defined any parameter less constructor in your base class, hence the error. Base class's parameter less constructor is called implicitly (if none is called using base keyword)

See: Using Constructors (C# Programming Guide) - MSDN

In a derived class, if a base-class constructor is not called explicitly by using the base keyword, the default constructor, if there is one, is called implicitly

To come over the problem you can either declare a parameter less constructor in base class or call the defined constructor explictily like:

public StereoCameras(string n) : base(n)

Also from the same link

If a base class does not offer a default constructor, the derived class must make an explicit call to a base constructor by using base.

Upvotes: 3

DeCaf
DeCaf

Reputation: 6096

When a class is instantiated the constructor of the base-class is always invoked before the constructor of the derived class. If the base class does not contain a default constructor you must explicitly define how to call the constructor of the base class.

In your case this would be (note the base call)

public StereoCameras(string n) 
   : base(n)
{
}

Upvotes: 0

undefined
undefined

Reputation: 1364

Use

  public StereoCameras(string n) : base(n)
    {


    }

Upvotes: 1

devdigital
devdigital

Reputation: 34349

You will need to invoke the base constructor:

public StereoCameras(string n) : base(n)
{
}

Then the assignment in the derived class is redundant.

Upvotes: 7

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