What is the difference between a static and a non-static class?

Question

May someone explain me the difference between these two classes?

I am always using the first one, but I the the second one often as well.

public static class Test
{
    public static void Method()
    {

    }
}


public class Test
{
    public static void Method()
    {

    }
}

`static` classes can only have static methods, fields and properties. So in your first example class `Test` may only have static members and in the second one both, static and instance members. — Leri, Feb 14 '13 at 09:12
[What query do you have that is not answered in the documentation](http://msdn.microsoft.com/en-us/library/98f28cdx.aspx)? — ta.speot.is, Feb 14 '13 at 09:12
http://msdn.microsoft.com/en-us/library/79b3xss3%28v=vs.80%29.aspx should help — AurA, Feb 14 '13 at 09:13
instead of typing a question here you must have typed in google thousands of results will be available — NetStarter, Feb 14 '13 at 09:30
@Christian, your question is an exact duplicate. To prevent downvotes always do a relevant search on SO first. — nawfal, Feb 14 '13 at 11:07

score 8 · Accepted Answer · answered Feb 14 '13 at 09:13

The first class is static, which means:

You can't use it as a type argument
You can't use it as a variable type
It will have no instance constructors (whereas your non-static class implicitly has a public parameterless constructor)
It will be implicitly abstract and sealed (even though that combination can't be static
It cannot contain any non-static members
It can contain extension methods (if it's a top level, non-generic static class)

Basically for utility classes which are only meant to contain static members, using a static class expresses that intent clearly and lets the compiler help you enforce that usage.

@ta.speot.is: I'll edit that to "instance constructors" – Jon Skeet Feb 14 '13 at 09:14 — Jon Skeet, Feb 14 '13 at 09:14
+1 Fine answer, as always. – ta.speot.is Feb 14 '13 at 09:15 — ta.speot.is, Feb 14 '13 at 09:15

score 1 · Answer 2 · answered Feb 14 '13 at 09:12

1

A static class cannot ever be instantiated, and can only have static members. In your second code snippet, you could create create an instance of Test, but not in the first.

answered Feb 14 '13 at 09:12

Thomas Levesque

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score 0 · Answer 3 · answered Feb 14 '13 at 09:13

Static class can only contain static member with is the first one. Second one is non static class and can contain both static and not static.

A class can be declared static, indicating that it contains only static members. It is not possible to create instances of a static class using the new keyword. Static classes are loaded automatically by the .NET Framework common language runtime (CLR) when the program or namespace containing the class is loaded, reference.

What is the difference between a static and a non-static class?

3 Answers3