CODEWITHSUNDEEP
.netstatic
sab669
sab669

Reputation: 4104

Is there a purpose behind making a private method static?

To my understanding, the only purpose of static is to enable a method to be called on the class itself, not an instance of it. But if the method is also private, you'll only be able to call it from within the class. So, is there a reason to declare something as both private and static? ReSharper recommends I make many of my methods static and I just don't see the point for the private ones.

Upvotes: 1

Views: 121

Answers (4)

Frederik Gheysels
Frederik Gheysels

Reputation: 56984

Performance. It is a (micro) optimization. The CLR needs to perform less steps to find the method that he needs to execute.

For a detailed explanation: http://msdn.microsoft.com/en-us/library/79b3xss3.aspx

A call to a static method generates a call instruction in Microsoft intermediate language (MSIL), whereas a call to an instance method generates a callvirt instruction, which also checks for a null object references. However, most of the time the performance difference between the two is not significant.

Upvotes: 1

Sriram Sakthivel
Sriram Sakthivel

Reputation: 73502

If your private method doesn't uses any instance methods or fields or properties then it is good to mark it as static.

Doing so, you get call opcode emitted in IL which will not perform any "null checking" before calling the method. where as instance methods emits callvirt opcode which does that "null checking" before calling the method. This helps you to get performance benefits.

Upvotes: 1

Tim Schmelter
Tim Schmelter

Reputation: 460340

Yes, if you have a (public or whatever) static method in the class and this method needs to use your private method. That doesn't work if it's not static.

public static void Foo1()
{
    Foo2(); // compile time error
}

private void Foo2()
{

}

Methods need to be instance methods only if they need to use fields or properties that are not static (among other reasons like inheritance). Therefore it's best practice to make it static.

Upvotes: 2

Sean
Sean

Reputation: 62542

You tend to see this if a method has been written that doesn't use the state of the object and is an implementation detail. You could just make it private, but some people prefer to make it static as well to fully indicate that the method doesn't touch the state.

Personally I'd just go with the private.

Upvotes: 0

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