Why static constructor not called before first call to class method

Question

According to Jon Skeet's artice C# and beforefieldinit and discussion in When is a static constructor called in C#? static constructor must be called before first call to a method of the class.

For some reason following code does not exhibit this behavior:

namespace AbstractAndStatic
{
    class Program
    {
        static void Main(string[] args)
        {
            StaticClass.Equals(1,2);
            StaticClass.foo();
        }
    }
    static class StaticClass : Object
    {
        public static void foo()
        {
            Console.WriteLine("Static");
        }
         static StaticClass()
        {
            Console.WriteLine("static constructor");
        }
    }
    class TestClass
    {
        public void deb()
        {
            Console.WriteLine("Test Class Debug");
        }
    }
}

I am debugging the above code using the Visual Studio Debugger. When the statement StaticClass.Equals(1,2); gets executed in the Main method the static Constructor is not getting called but when StaticClass.foo(); is executed it calls static constructor and then call the foo method.

I am little confused as why it didn't get called the the first time when executing StaticClass.Equals(1,2);.

I believe you need to override Object.Equals. As it stands, it's calling the base version. Every class inherits from object btw, so not necessary to do it manually. — Trevor Ash, Sep 11 '15 at 14:21
@RonBeyer: No, it's calling the `static Equals(Object, Object)` method. — Jon Skeet, Sep 11 '15 at 14:25
@JonSkeet Figured that out about 30 seconds before you posted that :) — Ron Beyer, Sep 11 '15 at 14:25

score 15 · Answer 1 · answered Sep 11 '15 at 14:24

15

Your call to StaticClass.Equals is actually just a call to Object.Equals(Object, Object), as StaticClass doesn't provide an applicable overload for Equals. If you look in the IL, you'll see that the compiler has resolved the call to just Object.Equals(1, 2). If you're not calling a method which actually involves the static class, it doesn't need to be initialized.

answered Sep 11 '15 at 14:24

Jon Skeet

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Note that " it doesn't *need to* be initialized" - it would still be valid behavior if framework decides to call static constructor earlier. – Alexei Levenkov Sep 11 '15 at 14:27
3

@AlexeiLevenkov: No it wouldn't. If a type has a static constructor, it's guaranteed that that is only executed *immediately* before the first reference to a member of that class. You may be thinking about when a type without a static constructor is initialized, which is considerably more lenient. Specifically, from the C# spec: "The execution of a static constructor is triggered by the first of the following events to occur within an application domain: An instance of the class type is created. Any of the static members of the class type are referenced." – Jon Skeet Sep 11 '15 at 14:29
@AlexeiLevenkov: See also: http://csharpindepth.com/Articles/General/Beforefieldinit.aspx – Jon Skeet Sep 11 '15 at 14:31

score 0 · Answer 2 · answered Dec 30 '22 at 09:35

0

The execution of a static constructor is triggered by the first of the following events to occur :

An instance of the class is created. Any of the static members of the class are referenced.

answered Dec 30 '22 at 09:35

Sunil Kumar

111
1
5

Why static constructor not called before first call to class method

2 Answers2

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