I'm creating a wcf project with a wpf client using mvvm design pattern,
Where do I need to implement the ICallback interface so I will be able to update the
window.
The callback contract should be implemented on the client-side. Likewise, the service contract should be implemented on the server-side, with which the server can send data to the client-side by the callback contract.
Please refer to my example of the previous post.
TimeOut exception in WCF while implementing duplex
the client sends a parameter to the server by using the service interface, subsequently, the server sends the handled result to the client with the callback contract so that the client application gets the updated.
Feel free to let me know if there is anything I can help with.
Related
I have created WCF service in .net.
It is called by Java client, how do I read parameters when service is being called?
Here is my code:
public string getMethod(string id, string name)
{
string str = name;
return str;
}
Here is my WPF application code, I have added web reference:
WebReference.Service1Soap client = new WebReference.Service1Soap();
string str = client.getMethod(id, name);
How do I read values of "id" and "name" called from Java client?
I am stuck here, please help me please!!
Any help would be greatly appreciated.
Thanks!!
The simplest way:
Run a local instance of the service in debug mode, or attach the visual studio debugger to WCF service host process.
Put a breakpoint in the getMethod() service operation code
Call the service with the java client.
Check the values using a watch or just mouseover.
EDIT.. from comments...
but I have set debug point, still it is not happening
That means that your java client call is not being made successfully. If your java client cannot call the service then you need to sort that out first. Please post a new question to address this, or there are plenty of stuff on google: https://www.google.co.uk/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=problem+calling+wcf+from+java
I need those parameter values in WPF application and I have to read
it. How to do it?
You can't send a message to a service and then have that data relayed to another client (WPF) unless you use callbacks via a duplex binding like wsDualHttpBinding, which is not a nice solution in my opinion. More reading here: http://www.codeproject.com/Articles/491844/A-Beginners-Guide-to-Duplex-WCF
If your java client needs to call into a WPF then you'll need to use ServiceHost inside your WPF application and host a WCF service from there. Look here for an example: http://blogs.msdn.com/b/brunoterkaly/archive/2013/11/01/wcf-service-hosting-how-to-host-a-wcf-service-from-inside-a-windows-presentation-foundation-application.aspx
EDIT 2
From Java, service client has been made successfully, and it is
getting the response. But how do I read parameters, and is there any
way or code, that "we come to know that .net service is being called".
Then the only thing you can do is either host the WCF service inside your WPF application, or use a duplex WCF binding on the service, and have the WPF application subscribe by registering a callback delegate. This way the service can call back to the client when something happens (a call is made).
Alternatively you could use a shared database which is updated with the call values when the java client makes the call. Your WPF app can then poll or use a SqlDependency to know when the data has changed.
I am using WPF and WCF for client server application. but i got a problem.
How to notify any update of client to other client.
Server(WCF)
Client1(WPF)
Client2(WPF)
if client1 enter any new record,immediatly notification send to client2 .
please suggest me best way to this complete task.
Thanks..
We have achieved such a requirement by using WCF Duplex Services. You can find enough information by googling about implementing a duplex service.
Basically;
clients send a client identifier (uniquely generated for each client) while registering to duplex service.
when WCF service updates data, pushes an update notification (including the notification source's client identifier) to all the registered clients
clients check for the originator's identifier when they got a notification. Discarding notifications caused by itself.
A few notes:
You can include everything about the updated data inside pushed notification payload to understand the change type or entity type.
Different bindings supported by duplex services. Usage of nettcpbinding is suggested if clients and service are in the same network and .net dependency is not a problem. You can find more information about support binding types from here or here.
I'm not sure if I'm on the right lines but this is what I'm trying to do, I have a Silverlight application and a WCF service, the Silverlight app "subscribes" to the WCF service using PollingDuplex and the service can send data to any connected clients which works.
The service is marked with [ServiceContract(CallbackContract = typeof(IServiceCallback))] and it is single instanced
The problem is there is another service which should be able to call a standard method on this service to pass it data that will get distributed to the connected Silverlight clients, but because of the above settings it requires it to use callbacks (I can't change the other service).
Is there a way to have both types of operations, callback and standard in the same service if that makes sense?
Thanks for your time
Yes. It is possible. I guess CallbackContract parameter will not stop you from using your service as a regular request/response service (though I have not tried it).
But for the same contract, you may have to define two end points with different bindings, one with PollingDuplexHttpBinding and another one with basicHttpBinding (with silverlight this is the only other option).
You have to make sure that you are calling the right operation from the clients using duplex and basic http bindings.
I am using a WCF service between the Client side UI (Silverlight 3.0) and the Data Layer. We are using NHibernate for Database Access. So please tell me if my below understanding is correct or not:
UI calls WCF for a Save Method (for eg).
The WCF has a Save method in it which actually encapsulates a Save method from the Data
Access Object.
The Data Access Object method of Save in turn encapsulates a default Save Method of
NHibernate which actually saves some Business Object/s into the Database.
Also can someone tell me that how do we pass objects from WCF to the UI (Silverlight 3.0) layer and vice versa. I have read that we use DTO for that. But how does a DTO work? Do they correspond to the 'Data Contracts' in the WCF? If not then is the DTO declared on WCF (server) side and Client side code as well?
No, not quite....
UI calls the client-side proxy method Save
the WCF runtime takes that call and all parameters being passed in, and serializes them into a message (typically a XML serialized message)
the WCF runtime sends the serialized message over some kind of a transport media (whatever it is)
on the server side, the WCF runtime takes the incoming message
the message is deserialized, the appropriate class and method to handle it are identified
typically: a new instance of a service class is instantiated to handle the request
the WCF runtime unpacks the parameters and calls that appropriate message on the service class
same steps - basically backwards - are done for response
Important point: the only thing between the client and the server is a serialized message (which could be sent by e-mail or pigeon courier) - there's no other connection - no "remote object call" or anything like that at all
marc_s mentions the client-side proxies, which can be generated via the service references in your Silverlight project. The generated proxies are decent enough and provide an async model for running requests from the Silverlight side; those will look mostly like remoted procedure calls.
Another approach is to use the leaner (but maybe more advanced?) channel factory directly. A simple example of that can be found here. Both methods take care of most of the serialization details for you.
I have a Linux/c client app that connects to a WCF web service over HTTP/SOAP (BasicHTTPBinding). I am using gSOAP. Can I implement the calls to the web-service using callback? I want to get the data asynchronously as call back.
Update: I have updated the question title.
WCF does support Duplex services, or those that have the ability to call back to the requesting client. Duplex services can be very complicated, as they are not only stateful, but they impose an contract implementation requirement on their clients.
Duplex services require the use of the WSDuplexHttpBinding. You will need to make use of the OperationContext to get a reference to the callback channel. Your clients MUST implement the callback contract in some class, and provide an InstanceContext that contains an instance of the callback class to the client proxy. Communications in both directions must be supported, and if the client is behind its own firewall or across the internet, this can be a complicated matter to resolve. Take care when writing duplex services...they are often more trouble than they are worth...so make sure you really need it. ;-)
The following page might be helpful:
http://msdn.microsoft.com/en-us/library/ms731064.aspx
The basicHttpBinding does not support callbacks. Another approach might be to have another method that the client can poll on for the response.
I am facing the same issue and the approach I am trying is to have a pair of gsoap servers/clients. Basically each process will listen on a port for soap calls and make its client calls to the other server. This way I avoid the polling or other complex approaches. The code has to be obviously thread safe for whatever business logic is implemented but the client/server combo pair is the simplest solution i have thought of so far.
Obviously one needs to be in control of both sides of the solutions the mentioned server and the mentioned client.