Why their is no Main() method in ASP .NET Web Application ?

In practice, this means that you should configure the container at the root of your application. In a desktop app, that would be in the Main method (or very close to it) In an ASP.NET (including MVC) application, that would be in Global.asax In WCF, that would be in a ServiceHostFactory etc. refe-"https://stackoverflow.com/questions/6277771/what-is-a-composition-root-in-the-context-of-dependency-injection"

When you execute a .NET console application, the common language runtime (CLR) looks for a specific entry point i.e. Your Static Main(). But ASPNET loads in the browser and passes through any incoming requests to the so-called "HTTP pipeline. The ASP.NET worker process activates the HTTP pipeline by creating a new instance of the HttpRuntime class and then calling its ProcessRequest method.