Static Initialization Design Ideas

Question

Currently, my MVC 3 app has a dependency on a static class that is initialized in the Application_Start() like this:

protected void Application_Start()
{
    MyDependency.Initialize();
}

With the static class looking more or less like the following:

public static class MyDependency
{
    public static void Initialize()
    {
        // Perform some I/O...
    }
}

This dependency is used in an attribute class, which comes with the caveat of having no run-time dependencies (hence the call to initialize in the Application_Start())

public class MyAttributeClass : ...
{
    public MyAttributeClass()
    {
        MyDependency.DoSomething(); //...
    }
}

Ultimately, other developers in our shop will have to use this API, and I'd like to see if there's a way to get rid of the line in the Application_Start() (an extra line of code in the Global.asax is likely to be a forgotten step)

For instance, is there a way the MyDependency class can "hook" into the pipeline without the needing to edit the Global.asax?

score 3 · Accepted Answer · answered Jan 31 '12 at 17:27

3

Use a static constructor in MyDependency. Here's the MSDN explaining the functionality static constructors provide.

By using a static constructor you should then be able to perform all the IO you need, as the constructor will be run before any static members are accessed.

answered Jan 31 '12 at 17:27

Lukazoid

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Yup this did it. I was under the (wrong) impression that the static constructor was called when the static class is first used. The MSDN article clarified things. Thank you – Didaxis Jan 31 '12 at 18:09
This certainly works. However, be very cautious that your static constructor does not throw any exception as has nasty consequences. See http://stackoverflow.com/a/4737910/117625 and the warnings in the MSDN link from the above answer. – Ed Chapel Jan 31 '12 at 18:32

score 0 · Answer 2 · answered Jan 31 '12 at 17:30

You should look at WebActivator. From the wiki:

WebActivator is a NuGet package that allows other packages to easily bring in Startup and Shutdown code into a web application. This gives a much cleaner solution than having to modify global.asax with the startup logic from many packages.

Essentially, you'll need something like:

using System;

[assembly: WebActivator.PreApplicationStartMethod(typeof(MyDependency), "Initialize")]
public static class MyDependency
{
    public static void Initialize()
    {
        // Perform some I/O...
    }
}

Static Initialization Design Ideas

2 Answers2