object does not contain a constructor that takes 0 arguments

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HI
I have a class that inherits from another one but i get this confusing error :

VB

Error   1  'WindowDecorator.Decorator' does not contain a constructor that takes 0 arguments

Error occurs in the constructor.

C#

public class ScrollDecorator:Decorator
    {
           protected Decorator decorator;

           protected float ScrollPosition;


       protected ScrollDecorator(Decorator _decorator)
        {
            this.decorator = _decorator;
        }


       public  void ScrollTo()
       {
           //return "";
       }

       public override void Draw()
       {

       }
    }

Posted 3-May-12 0:55am

Anele Ngqandu

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[no name] 3-May-12 7:31am

You are trying to instantiate an instance of the Decorator class that does not have a 0 argument constructor. What is so confusing about that?

5 solutions

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VJ Reddy · Answer 1 · 2012-05-03T01:23:00

The reason is that the base class Decorator does not contain a parameter less constructor i.e. a constructor which takes 0 arguments.

When the constructor of this derived class is called it will call the parameter less constructor of the base class as there is no explicit call to the constructor of the base class and since there is no parameter less constructor in the base class the above error occurs.

To avoid this error call the constructor of the base class with appropriate arguments as required for the constructor available in the base class as shown below:

C#

//Replace Arguments in base  with arguments as required for the 
//constructor of Decorator
protected ScrollDecorator(Decorator _decorator) : base(Arguments)
{
    this.decorator = _decorator;
}

Sangramsingh Pawar · Answer 2 · 2012-05-03T01:00:00

Solution 1

you missing default constructor
add following

protected ScrollDecorator()
      {

      }

Posted 3-May-12 1:00am

Sangramsingh Pawar

Comments

Anele Ngqandu 3-May-12 7:05am

Well Sir I tried that but still nothing thats why am confused by this

Prasad_Kulkarni 3-May-12 7:23am

Countered

Sangramsingh Pawar 3-May-12 7:31am

I think you missing to call base class constructor. It seems that base class has no default constructor, therefore u callbase class constructer that takes arguments

Anele Ngqandu 3-May-12 7:39am

thats true Sangramsingh

Nilesh Patil Kolhapur · Answer 3 · 2012-05-03T01:14:00

Solution 3

Hello,

i think this error occurred because you create object of the class without passing a value like

C#

Test t = new Test();

and your class don't have 0 arguments constructor

Best Luck
Happy Coding

Posted 3-May-12 1:14am

Nilesh Patil Kolhapur

Rahul Rajat Singh · Answer 4 · 2012-05-03T01:44:00

You are inheriting from a class and having the same class as instance member - wierd????

anyway looks like you base class has no default constructor and you will have to take the arguments that base class is expecting as derived class arguments and then pass them to the base class constructor as base(args) in derived class constructor.

C#

protected ScrollDecorator(Decorator _decorator, args) : base(args)
{
    this.decorator = _decorator;
}

Mr. Mahesh Patel · Answer 5 · 2012-05-03T01:04:00

type conflict

C#

public class ScrollDecorator:Decorator
    {
           protected Decorator decorator;

           protected float ScrollPosition;


       protected ScrollDecorator(Decorator _decorator)
        {
            this.decorator = _decorator;
        }


       public  void ScrollTo()
       {
           //return "";
       }

       public override void Draw()
       {

       }
    }

also add below constructor

C#

ScrollDecorator()
        {
            
        }

object does not contain a constructor that takes 0 arguments

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