Shared/Static variable in Global.asax isolated per request?

Question

I have some ASP.NET web services which all share a common helper class they only need to instantiate one instance of per server. It's used for simple translation of data, but does spend some time during start-up loading things from the web.config file, etc. The helper class is 100% thread-safe. Think of it as a simple library of utility calls. I'd make all the methods shared on the class, but I want to load the initial configuration from web.config. We've deployed the web services to IIS 6.0 and using an Application Pool, with a Web Garden of 15 workers. I declared the helper class as a Private Shared variable in Global.asax, and added a lazy load Shared ReadOnly property like this: Private Shared _helper As MyHelperClass Public Shared ReadOnly Property Helper() As MyHelperClass Get If _helper Is Nothing Then _helper = New MyHelperClass() End If Return _helper End Get End Property I have logging code in the constructor for MyHelperClass(), and it shows the constructor running for each request, even on the same thread. I'm sure I'm just missing some key detail of ASP.NET but MSDN hasn't been very helpful. I've tried doing similar things using both Application("Helper") and Cache("Helper") and I still saw the constructor run with each request. JavaScript questions and answers, JavaScript questions pdf, JavaScript question bank, JavaScript questions and answers pdf, mcq on JavaScript pdf, JavaScript questions and solutions, JavaScript mcq Test , Interview JavaScript questions, JavaScript Questions for Interview, JavaScript MCQ (Multiple Choice Questions)

Answer 1

You can place your Helper in the Application State. Do this in global.asax: void Application_Start(object sender, EventArgs e) { Application.Add("MyHelper", new MyHelperClass()); } You can use the Helper that way: MyHelperClass helper = (MyHelperClass)HttpContext.Current.Application["MyHelper"]; helper.Foo(); This results in a single instance of the MyHelperClass class that is created on application start and lives in application state. Since the instance is created in Application_Start, this happens only once for each HttpApplication instance and not per Request.