Invoking static constructors in base classes

[Hemanth]

Hi,

I have a base class with a static constructor and some abstract methods.
Derived classes implement these methods. From articles on the web, it appears
that there is no guarentee that this static constructor of the base class
would be invoked even if a an object of the derived class is created. Is this
correct ? Is there any way to ensure the base class's static constructor is
invoked before the derived class instance is constructed ?

Thanks
Hemanth

[Hemanth]

Goran,

This is exactly the same question that did come to my mind as well. You are
correct - I do have a static constructor in the base class. Both the base and
derived classes have no explicitly defined constructors - so the compiler
would have defined the default constructors for them. So, if the base class
constructor is called when the object is created, I was assuming that the
static constructor would be called as well. That doesn't seem to be happening.

I am not sure what more is required to be done.

Hemanth

"Göran Andersson" wrote:

Yes, I know that, but you are getting away from the original question.

The base class *does* have a static constructor. Hemanth wrote: "I have
a base class with a static constructor".

When the constructor of that base class is called, isn't it certain that
it's static constructor has been executed?

Stoitcho Goutsev (100) wrote:

This is where the confusion starts.
Static constructor is a language constrcution, .NET types have type
initializers. The difference is that c# class may not have static
constructor and at the same time the type to have type initializer.

Here is an example:

class Foo
{
public static int a = 10;
}

The class doesn't have static constructor, but the type will have type
initializer '.cctor'.

The big difference is that when the class has static constructor it also
will have type initializer, but the spec state that in this case the type
won't be marked as *beforefieldini t* which means the static construcotor
(will be called before instnace is created), however some of the base
classes may have type initializer, but not static constructor. For such base
class I don't think that there is guarantee that the static fields will be
initialized before isntatiating an object.

[Hemanth]

Stoitcho,

Thanks for the response. I shall try this and see if it works.

Hemanth

"Stoitcho Goutsev (100)" wrote:

Hemanth,

Yes, according to the information you provide there is no guarantee.

If you want to make sure you need to access at least one static field the
base class.
--

Stoitcho Goutsev (100)

"Hemanth" <he*****@discus sions.microsoft .com> wrote in message
news:CA******** *************** ***********@mic rosoft.com...

Hi,

I have a base class with a static constructor and some abstract methods.
Derived classes implement these methods. From articles on the web, it
appears
that there is no guarentee that this static constructor of the base class
would be invoked even if a an object of the derived class is created. Is
this
correct ? Is there any way to ensure the base class's static constructor
is
invoked before the derived class instance is constructed ?

Thanks
Hemanth

[Jon Skeet [C# MVP]]

Hemanth <he*****@discus sions.microsoft .com> wrote:

This is exactly the same question that did come to my mind as well. You are
correct - I do have a static constructor in the base class. Both the base and
derived classes have no explicitly defined constructors - so the compiler
would have defined the default constructors for them. So, if the base class
constructor is called when the object is created, I was assuming that the
static constructor would be called as well. That doesn't seem to be happening.

Could you post a short but complete program which demonstrates the
problem?

See http://www.pobox.com/~skeet/csharp/complete.html for details of
what I mean by that.

Here's an example which *does* execute both static constructors:

using System;

class Base
{
static Base() { Console.WriteLi ne ("Base.cctor "); }
}

class Derived : Base
{
static Derived() { Console.WriteLi ne ("Derived.cctor "); }
}

class Test
{
static void Main()
{
new Derived();
}
}

--
Jon Skeet - <sk***@pobox.co m>
http://www.pobox.com/~skeet Blog: http://www.msmvps.com/jon.skeet
If replying to the group, please do not mail me too