I have some member functions in three custom classes already created in my service. My objective is to use these custom classes on the client side to access the the member functions in the service. How do I expose these classes with all the member methods in them to the client?
I created these three classes in my service and marked them as "DataContract", and the member functions as "OperationContract". I created an Interface that defines these custom classes as OperationContracts returning an object of each of the classes through implementing them on a separate class.
Unfortunately, I couldn't achieve my objective because two of the classes have a constructor that takes some parameters, whereas the class with no constructor was accessible on the client side but I couldn't see the member methods in the class.
I need your hints on what to do.
That won't be easy to do. One way would be to share the DataContract-decorated types between the WCF server and its clients, i.e. add a reference to your service assembly in the client project and bind the service reference to that assembly reference.
However, that breaks contract implementation independence, as the exact same service assembly will need to exist on both the client and the server, and be kept synchronized every time it changes.
See here for more details.
By default and by design, WCF will only share contracts between client and server, e.g. your services ([ServiceContract]), their methods ([OperationContract]) and the data structures they operate on ([DataContract]).
WCF is a message passing system, so all the client and the server share in terms of the data being passed around is a XML serialized message format. When you add a service reference, the client-side proxy will generate a class for each [DataContract] that will look identical in XML serialized format - only the data is being moved back and forth - no behavior (no methods).
Basically, if you want to expose functionality, you need to have a service method decorated with a [OperationContract] attribute. Methods on your data classes will never be visible to the client - and that's by design.
If you control both ends of the communication and both are .NET based, you can "trick" your way around this limitation:
put all your service and data contracts into a separate class library assembly
use a reference to that common, shared assembly to create your service
before you do an Add Service Reference, add a reference to that common assembly on your client
In that case, the WCF runtime will reuse existing types from that common assembly, instead of re-creating them from the service description. And since that assembly contains the shared code that the server also uses, your classes also have their methods present.
It works ok in a .NET only scenario, but it's really kind of a dirty trick behind the proper service separation facade.
Related
I have a class implementing some audit methods (AuditcClass.cs). I have also implemented a WCF service that uses the AuditcClass.dll methods.
Now I need to be able also to reference the WCF service from within the AuditcClass. However I cannot simply use the generated proxies to reference it, since there are several conflicts with namespaces.
As first approach, I encapsulated the proxy within another namespace, solving many conflicts, but still introducing new ones with other general classes (as example, Exceptions namespace).
Is there an approach by which I could reference the web service within the class, even if the service uses the same class' methods and enums?
I was able to solve my issue by using the parameter /reference:<file path> of the svcutil tool: References types in the specified assembly. When generating clients, use this option to specify assemblies that might contain types that represent the metadata being imported.
This allowed me to exclude from the generated proxy the shared dlls avoiding reference conflicts.
I have tried googling for an answer since last week and haven't found anything. Maybe I'm just searching with incorrect key words...
Basically, we have a running WCF service and then we have a separate dll with another ServiceContract in it. We want to know if it is possible to expose the separate dll in the current running service and if one can, how?
We are still new to WCF, so please excuse if this is a stupid question. :(
We are working with .NET 3.5 SP1 and C#.
Regards
EDIT:
We want to separate our service into "modules". So the service implementations (Methods, ect) and contracts (Interfaces) are all in separate libraries. So lets say you have a module called "Clients". We want everything related to Clients to be in the same separate library (DLL) instead of one big base class that inherits from multiple interfaces. This is a huge service and we need multiple developers to work on different sections of the same service at the same time. This is what I've been instructed to figure out, but if it can be done then it can't. I hope this makes more sens??
Assuming you are asking how you can implement a service contract declared in one DLL in a service running in a separate DLL/Application:
Edits to match post edits
add a reference to the DLL with the service contract to the application containing the service
In the .cs file with service implmentation add a using statement for the namespace of the service contract
derive the service from the service contract (you will have problems if you define your service contracts as concrete classes rather than interfaces and you want to expose multiple contracts on your service
If self hosting then create a ServiceHost passing the type object of the service in the other assembly, if IIS hosting create an .svc file referencing the class in the other assembly as the service
Add a service element in the config file naming the fully qualified name of the service
Add an endpoint to the service at a unique address for the new contract
When you take the other assembly (dll) as a reference in the "main" project, then add a using directive to the file where the WCF service is instantiated. Then you can simply use the referenced service contract to set up a running service with the right endpoints and binding(configuration).
I guess one work around is you have a main ServiceHost hosting your WCFMainLib and then all your clients will connect to WCFMainLib.
WCFMainLib then acts like a proxy to connect to all other WCFModuleLib on localhost (or other servers) to fetch data.
WCFMainlib will implement the IWCFModuleLib1, IWCFModuleLib2 etc service contract interfaces and expose them to the WCFClient. Actual implementation of interfaces will then be a call to the actual WCFModuleLibs.
This may introduce some overhead, but overall also introduces several "features" that may benefit your boss or service availability.
OR, if you are just wanting to delegate programming work, maybe you can tell each team to work with partial classes for your WCFLib with each service contract on a partial class then do a nightly compile.
I have a class as DataContract in my webservice and it inherit from IEquatable.
But my siverlight webservice generated proxy class does not have equals. Can any one tell me why this is happening and is there a way achieve this?
WCF serializes only data from data contracts - no methods or behavior.
That's by default and by design - after all, WCF is a message passing system - you pass around serialized messages only.
WCF is NOT a "remote-procedure call" or "object remoting" system and thus, when creating a proxy, it will make sure the data signature on the wire will be identical (by means of XML serialization) - and that's all it does.
The only option to achieve what you're looking for would be to:
create a separate class library assembly that contains the service and data contract classes
reference that common contract assembly from both your server-side service code, as well as your client-side Silverlight app
when creating a service reference now, Visual Studio will reuse the common, shared classes in the assembly, and not re-create proxy data classes (and loosing the methods in the process)
I'm currently trying to call a WCF service dynamically See here, therefore, I'm trying to understand what happens behind, when I add a service reference by the GUI of Visual Studio... What's generated..? An object is created and an implicit reference is created...
Are the references contained in a specific container, a sort of pool?
When you add a service reference, VS generates a proxy class for the service. This class implements the interface defined by your service endpoint as its ServiceContract, so it appears to consuming code as if it were the actual object performing the operations, but it contains and uses the communication channel defined by the endpoint and bindings to call the exposed service methods.
If you do not have classes that conform to the signatures of the DataContracts required by the service, VS will generate those classes as well, but if you have already referenced classes that are marked identically to the DataContract (usually because you've referenced the project containing the DataContracts in the project with the client-side code) it will simply use those. Svcutil (the command-line tool) can be given a reference list of locations for these DataContracts as well.
What I am trying to accomplish is to be able to use List<>.Contains() using the custom data structure(s) returned by the WCF service.
I implemented the IEquatable<>.Equals but it's not really working on the client side. Contains() always returns false. I am wondering if the Contains() method is actually part of the class when it's put together on the client side.
No. Web services are generally meant to be platform-agnostic, so they define things like operation contracts (for operations performed on the server) and data contracts (for exchanging objects composed of simple data fields). But they don't define methods on objects as this would require knowledge of the client-side platforms. (For example, how would you marshal your IEquatable<>.Equals IL code to a Mac client?)
What you can do, if you have full control over your WCF service's clients, is deploy the same library to both the clients and the server. That is, you could put your data contract classes in Data.dll and deploy it to both the client and the server (as opposed to using the default proxy classes generated from the service contract on the client).
No this will not work. Actions like implementing IEquatable<T> is adding behavior to a type. Data contracts are only meant to specify data, not behavior. Behavior will not be copied down when the client adds a reference to your type.