Re: VS 2010 No method to override error - C# Discussion Boards

VS 2010 No method to override error

14-Dec-11 10:35

You are probably going to find your definitions (as well as examples) if you access MSDN.

Deborah Palmer McCain13-Dec-11 14:23

13-Dec-11 14:23

// CS0115.cs
namespace MyNamespace
{
    abstract public class MyClass1
    {
        public abstract int f();
    }

    abstract public class MyClass2
    {
        public override int f()   // CS0115
        {
            return 0;
        }

        public static void Main()
        {
        }
    }
}

After reducing errors to 1, I received the error (named in the Subject line) on line 14 of my project "No method to override". The problem is, Line 14 is blank.
When I went to MSDN, I found CS0115, but I don't know how to change it to work with my project. Should this be simple deduction and logical? Any help would be appreciated.

PIEBALDconsult13-Dec-11 15:27

PIEBALDconsult

13-Dec-11 15:27

Perhaps you forgot to tell the compiler that MyClass2 is supposed to derive from MyClass1?

Deborah Palmer McCain13-Dec-11 16:27

13-Dec-11 16:27

As I indicated to others who kindly tried to help, the given code is not mine, but rather the MSDN CS01150 to fix the error "no method to override". I just don't know how to change it, but will muddle through tomorrow. The error appears for a line which is blank...which threw me into a confused abyss.

This is the final error on many lines of code, so, of course,it will give me the most trouble in fixing.

I am just learning, so I truly appreciate the help.

PIEBALDconsult14-Dec-11 1:58

PIEBALDconsult

14-Dec-11 1:58

So where is your code? We can't help you without it.

BillWoodruff13-Dec-11 15:43

BillWoodruff

13-Dec-11 15:43

On this question: I think it would be helpful if you state your usage scenario here: what exactly are you trying to implement: how are the classes that implement these abstract classes going to use them ?

An abstract class that does not inherit from some other class is not going to have anything inside it that you can override.

If you changed your 'MyClass2' definition to this:

abstract public class MyClass2: MyClass1
{
    public override int f()
    {
        return 0;
    }

    public static void Main()
    {
    }
}

Now it will compile. But please note, that I am not sure this something you should do.

By the way, I find it very weird to see a 'Main entry point for execution inside an abstract class. I'm curious what your intent is in putting it there.

Override in "Abstract, Son of Abstract" ? I hope others on this forum, much more knowledgeable than I am regarding use of inheritance involving abstract classes, will comment on what it might mean for one abstract class to inherit from another abstract class: is this good (or common) practice ? The purpose of that is obscure ... to me.

"For no man lives in the external truth among salts and acids, but in the warm, phantasmagoric chamber of his brain, with the painted windows and the storied wall." Robert Louis Stevenson

Deborah Palmer McCain13-Dec-11 16:23

13-Dec-11 16:23

Thank you for your response, but the code I listed was the sample from MSDN, not mine. MSDN provided it as a way to fix the error in the compiler (CS0115)but I wasn't sure what to change to make it "my own". I questioned the abstract class, (like I would know?)...but MSDN indicated that the patch would activate CS0115 and fix the code error of "no method to override". As for today, the "chamber of my brain" is cooked in code.

Thank you again for trying.

Luc Pattyn13-Dec-11 19:08

Luc Pattyn

13-Dec-11 19:08

The concept may be shocking and new to you, however even Microsoft once in a while includes a little bug in their code, not all sample code snippets are correct. This has become a fact of life, you'll have to learn and live with it.

Smile | :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

PIEBALDconsult14-Dec-11 1:57

PIEBALDconsult

14-Dec-11 1:57

No the code correctly demonstrates how to generate the error.

Deborah Palmer McCain14-Dec-11 10:10

Re: VS 2010 No method to override error [Long Post]

14-Dec-11 10:10

At the risk of causing anyone to be rabid, why would one want to generate an error? Wouldn't someone go to MSDN for assistance? I probably should move to the rant page, as I am not posing legitimate issues.

Keith Barrow13-Dec-11 22:09

Keith Barrow

13-Dec-11 22:09

Deborah Palmer McCain wrote:
Should this be simple deduction and logical?

Pretty much always in IT

To work this through, a basic [incomplete] definition of a few keywords is probably helpful:

abstract: Whatever is declared abstract is missing or incomplete. A the class level this means that the class can't be instantiated directly, so it must be subclassed before use. For members of the class marked abstract you don't declare a body (e.g. <codelang="cs">public abstract int f();), and you must override in a subclass unless the subclass is also abstract. All abstract members are inherently virtual
virtual This isn't in the example, but it marks a method as being overridable, that is subclasses can (as opposed to must) override them in a non-abstract subclass.
override Members marked as overridden "replace" the superclass's virtual/abstract method. This can be summed up with the following code:

public abstract class Foo
{
    public abstract void Bar();
}

public abstract class Baz : Foo
{
    //Not-necessary to implement Bar() as Baz is also abstract
    public virtual void Quux()
    {
    }

    public virtual void Grault()
    {
    }
}

public class Corge : Foo
{
    public override void Bar()
    {
        //As this is non-abstract it must implement Bar()
    }

    public override void Quux()
    {
        //Overides virtual method
    }

    //Not-necessary to override Grault, but it is possible as per Quux().
}

Now to your problem. "No method to override", the word override only appears once, so we know this line is the problem:

public override int f()
{
...
}

So what are the preconditions for overriding? The method must override a method in a superclass that is marked as abstract or virtual. The method apparently being overridden is marked as abstract. It put italics on "apparently" as, in reality, MyClass2 doesn't have a superclass (as PiebaldConsultant has replied):

abstract public class MyClass2

the fix is now easy:

abstract public class MyClass2: MyClass1

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

Re: VS 2010 No method to override error [Long Post]

Deborah Palmer McCain14-Dec-11 10:03

14-Dec-11 10:03

Thank you for your detailed explanation of the issue. It helped alot, and even though the issue was resolved, your detailed assistance is appreciated.

Richard MacCutchan13-Dec-11 22:23

Richard MacCutchan

13-Dec-11 22:23

Well you have copied the sample code from here[^] which has been specifically written to generate a CS0115 error. What other result were you expecting to get?

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

prasun.r14-Dec-11 1:23

prasun.r

14-Dec-11 1:23

Haha that's a good one 5/5

Deborah Palmer McCain14-Dec-11 10:04

14-Dec-11 10:04

I plead ignorance (which is becoming less easy). There is now an arc in my learning curve.

Richard MacCutchan14-Dec-11 11:43

Richard MacCutchan

14-Dec-11 11:43

I usually plead senility, it works every time. Wink | ;)

Unrequited desire is character building. OriginalGriff
I'm sitting here giving you a standing ovation - Len Goodman

chat software

om_metab13-Dec-11 9:09

13-Dec-11 9:09

hello every boday
I want help to make my chat software worked over internet untill now it is run in LAN if any one have any idea please help and thanks

Dalek Dave13-Dec-11 12:43

Dalek Dave

13-Dec-11 12:43

Does this help?[^]

------------------------------------

I will never again mention that I was the poster of the One Millionth Lounge Post, nor that it was complete drivel. Dalek Dave

CCC Link[^]
Trolls[^]

Keith Barrow13-Dec-11 22:33

Keith Barrow

13-Dec-11 22:33

Have you really been at this for over a year[^]?

Sort of a cross between Lawrence of Arabia and Dilbert.[^]
-Or-
A Dead ringer for Kate Winslett[^]

om_metab13-Dec-11 23:51

13-Dec-11 23:51

waw oh my god yes Iam but until now Imaked in LAN not WAN

BobJanova13-Dec-11 22:47

BobJanova

13-Dec-11 22:47

If it works on a LAN then (unless it is using UDP broadcasting/multicasting) the software is fine, you just need to host it on an Internet-accessible server and set up the firewall appropriately.

om_metab13-Dec-11 23:39

13-Dec-11 23:39

but I didn't now how build and create Internet-accessible server

BobJanova14-Dec-11 1:05

BobJanova

14-Dec-11 1:05

1. take computer
2. plug in cable to router
3. ????
4. profit

(Part 3 also includes setting up port forwarding, and your ISP agreement needs to include a fixed domain name or (ideally) IP.)

You can also use a hosting service or a cloud service like Amazon's that will give you public IPs.

If you don't know about this, you probably shouldn't be trying to create Internet applications, because it's odds on that you will make dumb security mistakes as well.

om_metab15-Dec-11 8:57