asp.net: Will the static constructor be called every time there is a postback to a page?

Question

This could be a possible duplicate of Asp.net Static Variable Life time Across Refresh and PostBack but my query is a little different.

I have a web application with a page namely default.aspx. I have a public static class "MyClass" with a static constructor and a static property "MyProperty", This class is outside default.aspx.cs class.

The property of the static class is getting assigned on page load and on a button click.

Now, I know that static constructor of a type will get called only once whenever any property of the class is called or assigned. This is per AppDomain. After that static constructor will never get called.

I also know that An app domain is a .NET construct that provides a layer of isolation between loaded sets of assemblies within a process.

So my questions here are

1. Could someone please elaborate AppDomain in terms of asp.net? Any related link will also help.
2. I know that the page object is created and destroyed on each postback. So, for the following code, will the static constructor called every time there is a postback?

I tried debugging the code by keeping breakpoint on static constructor. The breakpoint got hit when the first time the page loaded but did not when I clicked on the button. But I am not sure if this will work the same way when hosted on IIS so wanted to get some expert opinion. The browser was IE10.

Please let me know if I have not framed any sentence correctly or stated something wrong.

Thanks in advance.

Regards,

Samar

public static class MyClass
{
    public static int MyProperty { get; set; }
    static MyClass()
    { 
    }
}

public partial class _Default : System.Web.UI.Page
{

    protected void Page_Load(object sender, EventArgs e)
    {
        MyClass.MyProperty = 2;
    }



    protected void Button1_Click(object sender, EventArgs e)
    {
        MyClass.MyProperty = 1;
    }
}

Answer 1

I think this page What ASP.NET Programmers Should Know About Application Domains does a pretty good job of explaining Application Domains.

The static constructor will only get called once and not per post back (as you've also seen), I don't believe you should expect any different behavior based on the browser or IIS.

Answer 2

App domain is not really relevant here. But if your curiosity is killing you: http://msdn.microsoft.com/en-us/library/ms173138(v=vs.80).aspx

The fact of the matter is, a static constructor will either be called zero times or once; but never more, per run of any application.

A static constructor gets called the first time a class is referenced when an application runs. Unless you restart the application, it will never be called again. If the class is never used, the static constructor will never be called.

So basically, the behavior you are describing in your question makes perfect sense. The page object will get reloaded every time, but the static constructor will only be called once.