What is difference between constructor and static constructor

Question

What is difference between constructor and static constructor and what is the benefit of using static constructor.

Akkiraju Ivaturi · Answer

A static constructor is used to initialize any static data, or to perform a particular action that needs performed only once . It is called automatically before the first instance is created or any static members of the class are referenced.
I am going to take the example from MSDN for the same and extend it to understand it better.
Public class Bus
{
static int wheels;
static Bus()
{
wheels = 4;
console.writeline("Each bus must have 4 wheels");
}
public void Drive()
{
Console.WriteLine(wheels.ToString() + "wheels drive the bus");
}
}
static void Main(...)
{
Bus b=new Bus();
b.Drive();
Bus anotherbus = Bus();
anotherbus.Drive();
}
Any number of object instances will have same number of wheels. Otherwise it is not a bus. In this example static constructor was called only once and the life time of the property wheels is set as 4 for the firstime and no object of this class can change the number of wheels. If you have any scenario like this, we must be using static constructor.
Hope this clears your question. Any questions, feel free to ask.
}

Jignesh Trivedi · Answer

hi,
Static constructor will be called first time when the class is referenced. Static constructor is used to initialize static members of the class.
In the non static class the private or public constructor will not be called. Static members will not be initialized either by private or public constructor.
Please refer
http://www.c-sharpcorner.com/uploadfile/AmitSaxena/constructor-vs-static-constructor/
http://msdn.microsoft.com/en-us/library/k9x6w0hc%28v=vs.80%29.aspx
hope this will help you.

Vulpes · Answer

A static constructor initializes the class as a whole rather than a particular instance of it. It cannot have a return type, access modifier or take parameters and it's signature always looks like this:
class MyClass {    static MyClass()    {       // code    } }
It's called automatically by the system before any other static method or instance constructor is called and cannot be called directly.
The benefit of having one is that you don't then need to remember to call a static method to do class initialization, which could cause problems if you forget to do so.
In contrast an instance constructor initializes a particular instance of a class. It can have an access modifier and take parameters and is normally called explicitly with the 'new' operator. However, if you don't provide an instance constructor then the system provides a public one which takes no parameters and does nothing except call its base class's parameterless constructor.