Why does refactoring generate private static method?

C

csharper

I am using Visual Studio 2010 for my web application in C# 4. When I
refactor my code to create a method, Visual Studio always generates
private static method such as

private static void MyMethod(blah blah blah){...}

instead of non-static protected method such as

protected void MyMethod(blah blah blah){...}

Is Visual Studio trying to tell us that we should write private static
method instead of non-static protected method for our web
application? I am confused.
 
C

csharper

I am using Visual Studio 2010 for my web application in C# 4. When I
refactor my code to create a method, Visual Studio always generates
private static method such as

private static void MyMethod(blah blah blah){...}

instead of non-static protected method such as

protected void MyMethod(blah blah blah){...}

Is Visual Studio trying to tell us that we should write private static
method instead of non-static protected method for our web
application?  I am confused.

Looks like I am not the only one who's wondering about this.

http://stackoverflow.com/questions/...ommand-in-visual-studio-create-static-methods
 
H

Harlan Messinger

csharper said:
I am using Visual Studio 2010 for my web application in C# 4. When I
refactor my code to create a method, Visual Studio always generates
private static method such as

private static void MyMethod(blah blah blah){...}

instead of non-static protected method such as

protected void MyMethod(blah blah blah){...}

Is Visual Studio trying to tell us that we should write private static
method instead of non-static protected method for our web
application? I am confused.

It isn't telling you anything of a general nature like that.

It has to generate a valid method, so it has to make some initial choice
about access modifiers and so on. It makes good sense that private would
be the default in this situation, because the code you are extracting
from method A in class T into method B is code that, before the
extraction, was only executed within method A. Therefore, unless you
make any other changes, the new method B will only be called from within
method A, so there is no reason why method B should be visible outside
of class T.

As far as I can tell, the generated method will be static if the code
you are extracting contains no mentions of instance members. For
example, given this test code:

class Class1
{
private int i;
private string s;

public void A()
{
i = i + 2;
s = i.ToString();
System.Diagnostics.Debug.Print("Hello");
System.Diagnostics.Debug.IndentLevel = 7;
s = s + s;
i = i + 3;
i = i + s.Length;
s = i.ToString();
i = i + 1;
i = i + s.Length;
s = i.ToString();
}
}

When I extract the two lines that invoke Debug members into method B and
the three lines after it into method C, I get

class Class1
{
private int i;
private string s;

public void A()
{
i = i + 2;
s = i.ToString();
B();
C();
s = i.ToString();
i = i + 1;
i = i + s.Length;
s = i.ToString();
}

private void C()
{
s = s + s;
i = i + 3;
i = i + s.Length;
}

private static void B()
{
System.Diagnostics.Debug.Print("Hello");
System.Diagnostics.Debug.IndentLevel = 7;
}

It figures that if the code makes no use of the instance, then the
method created from it doesn't need to be instance-specific.
 
M

Mr. Arnold

csharper said:

It doesn't matter Java or .NET OOP is OOP (Object Oriented Programming).
If the method was public static, then another class can access the
public static method without having to instantiate an class as an
instance of an object first, before accessing the public method in the
class/object.

http://leepoint.net/notes-java/flow/methods/50static-methods.html

Why declare a method static?

The above mean() method would work just as well if it wasn't declared
static, as long as it was called from within the same class. If called
from outside the class and it wasn't declared static, it would have to
be qualified (uselessly) with an object. Even when used within the
class, there are good reasons to define a method as static when it could
be.

•Documentation. Anyone seeing that a method is static will know how to
call it (see below). Similarly, any programmer looking at the code will
know that a static method can't interact with instance variables, which
makes reading and debugging easier.
•Efficiency. A compiler will usually produce slightly more efficient
code because no implicit object parameter has to be passed to the method.

http://www.eggheadcafe.com/articles/20020206.asp

You access static methods and fields associated with a class differently
that you access them as objects (instances of a class). Instead of
specifying the name of the instance to access the method
(cp1.GetMaxCashAdvance) you will specify the name of the class:
CreditCardAccountPremium.GetMaxCashAdvance(). The static modifier can be
used with fields, methods, properties, operators, and constructors, but
cannot be used with indexers, destructors, or types. C# trashes the
whole concept of global functions, variables, and constants. Instead,
you can create static class members, making your C# code not only easier
to read, but less likely to cause naming and other conflicts.
 

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