VS 2010 No method to override error

[BillWoodruff]

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 McCain]

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.

[Deborah Palmer McCain]

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.

[Luc Pattyn]

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. :)

Luc Pattyn [My Articles] Nil Volentibus Arduum

[Keith Barrow]

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. 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.[

[Lost User]

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 r]

Haha that's a good one 5/5

[PIEBALDconsult]

No the code correctly demonstrates how to generate the error.

[PIEBALDconsult]

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

[Deborah Palmer McCain]

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

[Deborah Palmer McCain]

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

[Deborah Palmer McCain]

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.

[Lost User]

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

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