ASMX equivalent of Page_Init?

I have some code I would like to execute very early in the lifecycle 开发者_开发知识库of a call to an ASMX function. For our ASPX pages, this code is in the Page_Init() function on a base class, from which all our ASPX pages inherit.

Is there an ASMX equivalent to the ASPX's Page_Init() function?

Better yet, is there an ASMX lifecycle diagram like the ASPX one? http://msdn.microsoft.com/en-us/library/ms178472.aspx

If there is an ASMX equivalent to Page_Init(), I assume I can implement code in a common base class, from which all my ASMX classes can inherit, correct?

EDIT: Great responses - thanks for your help!

There isn't really such a thing in an asmx web service, System.Web.Services.WebService has no events. Your best bet is to create a default constructor and put it in there.

e.g.

    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    public class WebService1 : System.Web.Services.WebService
    {
        private string strRetVal;

        public WebService1()
        {
            strRetVal = "Hello World";
        }

        [WebMethod]
        public string HelloWorld()
        {
            return strRetVal;
        }
    }

Very good question!

Not entirely sure, but i believe that execution of ASMX Web Services is slightly different to ASPX Pages - there is no "Page Lifecycle" (i.e there is no initialization of controls in order to render HTML - as the response is generally XML).

Your only options would be to hook into one of the Application events in Global.asax - the only suitable event would be Application_PreRequestHandlerExecute.

You can try Application_BeginRequest, but i believe this is only for ASP.NET Page Requests, not Web Service calls.

You're other option (as you said) is to create a base class for your web services, then call the common base method in all of your web methods at the very first line. You would have to repeat this call in ALL of your web methods. Or if you have all your web methods in a single web service file (ASMX), then just create a regular static method (dont decorate it with the WebMethod attribute) and call that.

They do not have similar 'life cycles'

The only 2 'events' are the Request and the Response.