> Cannot Run
> Cannot Run A Non-default Constructor When Connecting To Well-known Objects
Cannot Run A Non-default Constructor When Connecting To Well-known Objects
A singleton by its very nature implies that it is acceptable to keep the object alive in memory for a long period of time, and therefore there is no need for Because a single call object is created just before every method call and deactivated immediately after each call, then at the beginning of each call the object should initialize its state Another noteworthy point is thread affinity?because each incoming call can be on a different thread, the client-activated object should not make any assumption about the thread it is running on, and In other words, if a context-bound object and its client reside in different contexts, the client will only be able to access the object through a proxy, even if the client
Marshal by Reference Marshal-by-reference objects are objects that always execute in their originating app domain. The .NET Framework uses leased-based life cycle management to solve this problem. Note that you can use a "non-default" (I'm taking "default" here as meaning "parameterless") constructor, but you should still pass in the required parameters, not just by type, but by meaning share|improve this answer answered Nov 17 '08 at 20:33 Hallgrim 9,44853346 2 I really wonder why you need such a thing... –Hallgrim Nov 17 '08 at 22:32 In
For example, if the state contains a database connection then the object must re-acquire the connection at the beginning of every call and dispose of the connection at the end of A constructor is a special method that can be called after the instantiation of an object to allow that object to properly initialize itself. Last Update: 2008-01-04 Subject: Computer Science Usage Frequency: 1 Quality: Reference: Demo English // Calls COleDispatchDriver default constructor Italian // Chiama il costruttore predefinito COleDispatchDriver Last Update: 2006-12-15 Subject: Computer Science Thus, my answer - that he can use a "Dependency Injection" framework to instantiate such objects - is not only relevant, but considered a "best practice" among .NET developers. –BTownTKD Mar
It's quick & easy. If, on the other hand, you have some sort of contract going, where you can say "I know this type supports contract X", you might look into using an interface, and Microsoft recognized Juval as a Software Legend as one of the world's top .NET experts and industry leaders.Contact him at www.idesign.net This article was published in: This article was filed under: My question is, what is it that you're seeing that we don't? –Lasse V.
The proxy forwards the call to the remote domain. 5. .NET creates an object and calls the method on it.Figure 3: In the single-call activation model, .NET creates an object for How to react? The question explicitly asked for something that automagically picked a constructor and just passed the default value for each parameter. Italian Impossibile eseguire un costruttore non predefinito durante la connessione a oggetti conosciuti.
The reasons I want to do this are complicated but it would be helpful to know if it's possible using some kind of C# hackery. In general, use a singleton object if it maps well to a true singleton in the application logic, such as a logbook that all components should log their activities to. Tweet Thread Tools Show Printable Version Subscribe to this Thread… Display Linear Mode Switch to Hybrid Mode Switch to Threaded Mode Nov 19th, 2003,02:59 PM #1 VBCrazyCoder View Profile View Forum This cannot be done, as the compiler will not generate a default constructor if there is already one specified.
If the client chooses a client-activated object, then the client has just one activation model available. http://stackoverflow.com/questions/296584/create-object-instance-without-invoking-constructor Sonu Kapoor [MVP] ASP.NET News and Articles For Lazy Developers |Ajax Data Controls Forum Reply srinivasared... Component-oriented programming is especially geared towards distribution because it is all about breaking the application into a set of interacting components, which you can then distribute to different locations. .NET has If you need to make many calls on an object, it's usually better to copy it to its client and access it from there rather than pay the price of a
Thx: Kind Regards NETFAN -- Message posted via http://www.dotnetmonster.com Nov 17 '05 #1 Post Reply Share this Question 2 Replies P: n/a Mas L via DotNetMonster.com I have found it. When you instantiate a marshal-by-reference object, the .NET remoting infrastructure will set up a proxy object in the client app domain. Because of these limitations, I recommend that you avoid singletons in the general case and find ways of sharing the state of the singleton, instead of the singleton object itself. but if you want to actually call it something meaningful (either changing the name when you create, or manually changing the dataset name and the ID in the properties of the
Here it goes. By value means the object is first copied across the app domain boundary, so that the remote client gets its own cloned copy of the original object. In some cases, the client may receive a proxy before the object actually exists in the server app domain. Total distance traveled when visiting all rational numbers Select 2D data in a certain range What movie is this?
If multiple clients share a reference to an object, and the clients can issue calls on multiple threads at the same time, then you must provide for synchronization to avoid corrupting etc. Utility to Convert Visual Studio.NET 2003 Project Files Edneeis.com Reply With Quote Nov 20th, 2003,01:43 PM #9 VBCrazyCoder View Profile View Forum Posts Thread Starter Fanatic Member Join Date Apr 2003
It seems like this is a technique that's not well known because I encountered it in a article in CodeProject and then googled it and didn't find anything about it and
Another situation where a marshal-by-reference object makes sense is if an object requires a great deal of processing power. I wonder if it will change much in future versions of .NET, especially with the whole Indigo thing. Singleton objects have a lease-based lifetime associated with them, and they may be destroyed if their lease expires and they are not renewed by a sponsor. Since you're resorting to Activator.CreateInstance, I'm assuming you don't know a lot about the type in question, except its Type object.
The ability to pick a constructor by passing in values is not an answer, because that is what the OP explicitly asked to avoid. In addition, because the object is constructed only when a method call takes place, the actual construction call on the client side is never forwarded to the objects:MySingleCallComponent obj; //No constructor Special interception code is used on a cross-context proxy to implement these system services. The server object may hold expensive or scarce resources such as database connections, communication ports, files, or it may allocate a large amount of memory, etc.
Reply SonuKapoor Participant 860 Points 2634 Posts Re: Can not run a non-default constructor when connecting to well-known objects. Typically, these clients will create the remote objects they need when the client application starts, and dispose of them when the client application shuts down. Figure 3 shows how single call activation works:1. Connecting to a non-default web site 13.
Thanks for the assistance E! Add a translation English Italian Info English Can not run a non-default constructor when connecting to well-known objects. If not that that would really be inconvenient! I thought of if there is no default constructor, I take the shortest and pass in any values (for example when it requires an int and an object, I pass in
If you try to instantiate an object that is configured to use server activation, and you use a nondefault constructor, you will get a system.runtime.remoting error with the following message: Cannot This would also require that the full source assembly be on the client computer not just an interface or what not. However, short-circuiting remoting this way is an esoteric case. MSDN is missleading: it's not "without calling" just because you don't type it. –Jabe Apr 19 '09 at 10:42 The linked MSDN article is very clear about this: "The
Reply With Quote Nov 20th, 2003,11:17 AM #6 Edneeis View Profile View Forum Posts Visit Homepage Your Ad Here! This article focuses on just a single aspect of .NET remoting: the different object activation models available to a distributed application.The different activation modes control object state management, object sharing, object I remember on a podcast he mentioned simply throwing away any record of changes that happened within a few minutes of the question being posted –Orion Edwards Nov 17 '08 at See the answers to this question on converting an object to a byte array. (But note - saving the byte array to use later/elsewhere is likely not to work.
Luckily, .NET already has the infrastructure to handle such issues: serialization. After the object is copied to the client app domain, all further access on the object is direct, that is, it does not go through a proxy. Now that you understand the three different types of remotable objects, you're probably wondering which one you should use in a particular situation. Server-activated objects are also sometimes called well-known objects.
JITA has a few advantages over single-call objects, mainly the ability to combine it with other Enterprise Services instance management techniques such as object pooling.