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.NET Forum / .NET Framework / CLR / September 2003Object Instantiation
I'm trying to understand the details of calling "New" on a managed object. In the COM world, calling "New" caused the following superset of events: 1. The SCM resolves the path to the class in the registry by using its CLSID. 2. The object's class factory creates its instance in memory, and the instance's pointer is returned to the client by the SCM. 3. The client calls the IUnKnown AddRef() method on the object to increment its internal reference count. As far as I've been able to determine, the following events occur when you call "New" on a managed object: 1. The .Net runtime looks for the requested assembly by querying the GAC first, then any CodeBase entries in the .config file, and finally by probing. 2. The Garbage Collector allocates space in the managed heap for an instance of the object. 3. The runtime creates an instance of the object Questions: 1. Am I missing any steps? 2. COM objects provide class factories for instantiation. How does the .Net runtime create object instances? Thank you for your input! Hello, The following document should describe how assemblies are located: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cpguide/htm l/cpconassemblies.asp. This should provide you with information as to how types are resolved. As for object instantiation, assemblies contain enough information (or metadata) to fully describe their layout. As a result, the runtime is fully responsible for allocating and initializing type instantiations based on type resolution and constructor signatures. Because of the runtime's garbage collection mechanism, AddRef and Release are no longer necessary in managed code (barring COM interop, of course). Cheers, Simon -------------------- >Content-Class: urn:content-classes:message >From: "Hanuman" <dhaeseler@ozcap.com> [quoted text clipped - 44 lines] > >Thank you for your input!  SignatureThis posting is provided "AS IS" with no warranties, and confers no rights. Use of included script samples are subject to the terms specified at http://www.microsoft.com/info/cpyright.htm Note: For the benefit of the community-at-large, all responses to this message are best directed to the newsgroup/thread from which they originated. Thank you! >-----Original Message----- >Hello, [quoted text clipped - 64 lines] >> >>Thank you for your input! >As for object instantiation, assemblies contain enough information (or >metadata) to fully describe their layout. As a result, the runtime is fully >responsible for allocating and initializing type instantiations based on >type resolution and constructor signatures. But I've seen something different when you try to instantiate an object derived from ContextBoundObject. I used debug to monitor the process. When you call new a ContextBoundObject =============== Class A : ContextBoundObject { } A a = new A(); =============== You won't get an object of type A, you will get __TransparentProxy instead. a.GetType() is not available at the watch window, but in local variable window, you will see it's type of __TransparentProxy. But if you say: Type T = a.GetType(); in your code, use your debugger, you will see T is typeof(A). It's just weird, I am not sure how the runtime process the ContextBoundObject. Calvin Calvin, __TransparentProxy is an internal CLR type used for context bound and remoted objects. This type often wraps the true type. The debugger only exposes types and fields, which means that it is not smart enough to unwrap the object to show you the true type. For a *much* more detailed explanation of these internal types, please see Chris Brumme's blog entry on this subject: http://blogs.gotdotnet.com/cbrumme/PermaLink.aspx/24e9e5f5-9923-4cf9-b097-9c 018c69d5cb Cheers, Simon -------------------- >Content-Class: urn:content-classes:message >From: "Calvin" <szguoxz@hotmail.com> >Sender: "Calvin" <szguoxz@hotmail.com> >References: <0a1a01c3448a$7477a6c0$a101280a@phx.gbl> <u6uG$WNRDHA.2012@cpmsftngxa09.phx.gbl> >Subject: RE: Object Instantiation >Date: Tue, 8 Jul 2003 11:58:22 -0700 [quoted text clipped - 50 lines] > >Calvin
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