LINQ in global.asax

After creating a fresh ASP.Net web application, I created the global.asax file by right clicking the project, selecting add "New Item..." and selecting "Global Application Class". I don't think it gives you that option after you already have a global.asax file, so it's important to do it before you tinker with stuff. Here is the code behind it gave me by default:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.SessionState;
namespace WebApplication2
{
    public class Global : System.Web.HttpApplication
    {
        protected void Application_Start(object sender, EventArgs e)
        {
        }
        protected void Session_Start(object sender, EventArgs e)
        {
        }
        protected void Application_BeginRequest(object sender, EventArgs e)
        {
        }
        protected void Application_AuthenticateRequest(object sender, EventArgs e)
        {
        }
        protected void Application_Error(object sender, EventArgs e)
        {
        }
        protected void Session_End(object sender, EventArgs e)
        {
        }
        protected void Application_End(object sender, EventArgs e)
        {
        }
    }
}

And the contents of the global.asax file:

<%@ Application Codebehind="Global.asax.cs" Inherits="WebApplication2.Global" Language="C#" %>

Notice that LINQ is included by default (also note that CP decided to take away some of the blank lines... so the file doesn't appear exactly as it did when I copied it).

First of all, you can use an equivalent of using statements without codebehind:

<%@ Import Namespace="System.Linq" %>

...however I personally prefer the codebehind style because it works the same way as normal C# code, and has greater flexibility.

Converting to codebehind

When you create a project via File->New->Website, VS will create a website where the auto-generated default items are in the non-codebehind/"scripty" style of ASP.NET coding. If you prefer using the codebehind style, you can still easily convert to using the codebehind arrangement for Global.asax, either by deleting or re-adding, or by following these steps:
1. Add a class file the normal way, called Global.asax.cs - if you created your site via the Website template, make sure your class file goes in App_Code.
2. Make the class inherit from HttpApplication.
3. Move your code into the class file, and add the Codebehind and Inherits attributes to <%@Application %> in Global.asax, as I show in my samples below.

If you create a website by using File->New->Project/Solution and selecting one of the Web Application templates, the default files will be generated via the codebehind coding style. This is what I generally prefer.

Sample codebehind global.asax

Here is a sample of what a codebehind-style global.asax and global.asax.cs would look like:

global.asax

<%@ Application Codebehind="Global.asax.cs" Inherits="MyNamespace.Global" Language="C#" %>

global.asax.cs

using System;
using System.Web;
//as many using's go here as you please ;)

namespace MyNamespace
{
    public class Global : HttpApplication
    {
        protected void Application_Start(object sender, EventArgs e)
        {
            //code here...
        }
        
        //other events and methods...
    }
}