I've been looking for it, for quite and while, and I didn't really find anything that cover how to pull data trough duplex connection for Silverlight (pollingHttpDuplex).
I have setup basic sub/pub application with duplex.
Now I wanted to get list of topics, that are users are connected to. My first thought, was to setup simple DataContract (with only one field TopicName), then get data from Dicionary that I've been using to store current topics.
So I end up with something like this:
[OperationContract]
public List<Topic> GetTopicList()
{
List<Topic> topicList;
topicList = (from p in _sessionIDTopic
select new Topic
{
TopicName = p.Value
}).ToList<Topic>();
return topicList;
}
[DataContract]
public class Topic
{
[DataMember]
public string TopicName { get; set; }
}
I'm doing something wrong here. Because big question is how to send this to the client (Silverlight 4), and bind it to controls ?
Also duplex is essential for application. Changing it for anything else is not an option.
Using a duplex connection here doesn't have any effect on how you get the data to the client. The example you specified looks like simple one way communication. To do that, your client project needs a service reference to the server, and the generated proxy will provide the methods the client needs to access the operations on the server.
I think you should start by looking at a simple WCF example project to see what I mean. If this is not your problem, please rephrase the question.
Related
Say this is my classes
#Entity
public class Library{
...
}
#Entity
public class Book{
#Load
#Parent
#ApiResourceProperty(ignored = AnnotationBoolean.TRUE)
private Ref<Library> libraryRef;
#Ignore
private Library library;
}
I want to send List<Book> to the "android" client: I don't want the android client to get libraryRef but I want the client to get library
Here is the data access method I have now
public static List< Book > getAllBooks(){
return OfyService.ofy().load().type(Book.class).list();
}
My endpoint will just return List<Book> to android. I believe I have accomplished the first part: make sure datastore does not store library but libraryRef. But how do I accomplish the second part: make sure the client gets library?
I am sure it is not yet loaded. How do I make sure it is loaded? Do I have to use my own for-loop for iteration?
My advice for anyone working with code shared between client and server is to make a clean separation between your API objects and your domain objects. It's a little more work up front to make DTOs but it makes your whole system more flexible - if you want to change your domain objects, you don't risk breaking a zillion mobile phone apps that are on a slow (or nonexistant) upgrade cycle.
I am developing a small instant messaging application that makes use of few DomainServices on the server side. Trying to access the domain service URL, I encounter the following error:
"ContractDescription 'AppInitService' has zero operations; a contract must have at least one operation".
The domain service Url is this one:
http://givemeword.net/chat/Services/IM-Chat-UI-Web-DomainServices-AppInitService.svc
You can find the domain service class below:
namespace Chat.UI.Web.DomainServices
{
[EnableClientAccess()]
public class AppInitService : DomainService
{
private System.Security.Principal.IPrincipal _user;
private readonly Chat.UI.Web.Services.AppInitService _appInitService;
public AppInitService()
{
_appInitService = new Chat.UI.Web.Services.AppInitService();
}
public InitUserSettingsDTO InitUserSettings(Guid userId)
{
var initUserSettingsDTO = new InitUserSettingsDTO();
return initUserSettingsDTO;
}
}
}
As you can see, I am using a complex type as the return type of the only function of the domain service.
What I can not figure out is why on my testing Windows Server 2012 (not a development machine, just a virtual machine used for testing) or on my development machine everything runs without any problem, but on the hosting account it raise the error above.
Does anyone has any idea about this?
Thank you
Try adding the [Invoke] attribute to your InitUserSettings method:
[Invoke]
public InitUserSettingsDTO InitUserSettings(Guid userId)
{
var initUserSettingsDTO = new InitUserSettingsDTO();
return initUserSettingsDTO;
}
Make sure your web.config is set up as described here: http://msdn.microsoft.com/en-us/library/ff426912(v=vs.91).aspx
Being exasperated with this strange situation and the low support I received from the web hosting company, I have tried the same thing with another web provider. As I was thinking, it was working this time with no problems, so my assumption that the original provider had poor support for WCF RIA Services (or maybe other unidentified problem) was correct.
I want to send data from WCF to my desktop application while executing a service method.
The WCF service is hosted in windows service.
For example: In my service I am counting from 1 to 100 and when I am hitting 10,20,30 etc I want to set that value on my textbox.
This may be done using duplex channels services:
http://msdn.microsoft.com/en-us/library/ms731064.aspx
Be careful however : this will not work if the server can't reach the client : for example if you are behind a proxy.
I've simpy passed that with get/set like below: (Maybe someone will search smthing similar in future)
public class CallbackHandler : WCFService.IWCFServiceCallback
{
public ListBox LtBox { get; set; }
public void Message(string result)
{
LtBox.Items.Add(result);
}
}
InstanceContext instanceContext = new InstanceContext(new CallbackHandler() { LtBox=this.ltBox });
Where ltBox is my Listbox in desktop application.
Thanks all for help.
I tried to solve by myself, but... Looks like I need help from people.
I have Business Silverlight application with WCF RIA and EntityFramework. Access to Database I get via LinqToEntites.
Common loading data from database I making by this:
return DbContext.Customers
This code returns full Customers table from DataBase. But sometimes I do not need to show all data. Easy way is use linq filters in client side by next code:
public LoadInfo()
{
...
var LO1 = PublicDomainContext.Load(PublicDomainContext.GetCustomersQuery());
LO1.Completed += LO1Completed;
...
}
private void LO1Completed(object sender, EventArgs eventArgs)
{
...
DatatViewGrid.ItemsSource = null;
DatatViewGrid.ItemsSource = loadOperation.Entities.Where(c=>c ...filtering...);
//or PublicDomainContext.Customers.Where(c=>c ...filtering...)
...
}
However this way has very and very important flaw: all data passing from server to client side via DomainService may be viewed by applications like Fiddler. So I need to come up with another way.
Task: filter recieving data in server side and return this data.
Way #1: LinqToEntites has a beautiful projection method:
//MSDN Example
var query =
contacts.SelectMany(
contact => orders.Where(order =>
(contact.ContactID == order.Contact.ContactID)
&& order.TotalDue < totalDue)
.Select(order => new
{
ContactID = contact.ContactID,
LastName = contact.LastName,
FirstName = contact.FirstName,
OrderID = order.SalesOrderID,
Total = order.TotalDue
}));
But, unfortunately, DomainServices cannot return undefined types, so this way won't work.
Way #2: I found next solution - make separate DTO classes (DataTransferObject). I just read some samples and made on the server side next class:
[DataContract]
public partial class CustomerDTO
{
[DataMember]
public int ISN { get; set; }
[DataMember]
public string FIO { get; set; }
[DataMember]
public string Listeners { get; set; }
}
And based this class I made a row of methods which return filtered data:
[OperationContract]
public List<CustomerDTO> Customers_Common()
{
return DbContext.Customers....Select(c => new CustomerDTO { ISN = c.ISN, FIO = c.FIO, Listeners = c.Listeners }).ToList();
}
And this works fine, all good...
But, there is strange problem: running application locally does not affect any troubles, but after publishing project on the Web Site, DomainService returns per each method HTTP 500 Error ("Not Found" exception). Of course, I cannot even LogIn into my application. DomainService is dead. If I delete last class and new methods from application and republish - all works fine, but without speacial filtering...
The Question: what I do wrong, why Service is dying with new classes, or tell me another way to solve my trouble. Please.
U P D A T E :
Hey, finally I solved this!
There is an answer: Dynamic query with WCF RIA Services
Your best shot is to find out what is causing the error. For that, override the OnError method on the DomainService like this:
protected override void OnError(DomainServiceErrorInfo errorInfo)
{
/* Log the error info to a file. Don't forget inner exceptions.
*/
base.OnError(errorInfo);
}
This is useful, because only two exceptions will be passed to the client, so if there are a lot of nested inner exceptions, you should still be able to see what actually causes the error.
In addition, you can inspect the error by attaching the debugger to the browser instance you are opening the site with. In VS2010 this is done by doing [Debug] -> [Attach to Process] in the menu-bar.
I have a Visual Studio solution with a Silverlight project, and a web project which hosts the Silverlight app. The web project also contains an ASMX web service which is called by the Silverlight ap.
As described below, certain calls to the web service work fine, and yet others cause a CommunicationException to be thrown, wrapping a WebException - both with the message "The server returned the following error: 'not found'".
Firstly, here's my original method, which failed as described above (entity names changed for simplicity):
[WebMethod]
public Customer GetCustomer(int id)
{
CustomerDataContext dc = new CustomerDataContext();
return dc.Customers.SingleOrDefault(x => x.Id == id);
}
Secondly, to debug the problem I took Linq to SQL and the database out of the picture, and the below code worked fine:
[WebMethod]
public Customer GetCustomer(int id)
{
Customer c = new Customer() { ID=1, Name="Bob", History = new EntitySet<CustomerHistory>() };
return c;
}
Third, thinking about this, one difference between the two methods is that the first one would include values in the customer history. I extended the second method to include this, and it started failing again:
[WebMethod]
public Customer GetCustomer(int id)
{
Customer c = new Customer() { ID=1, Name="Bob", History = new EntitySet<CustomerHistory>() };
c.History.Add(new CustomerHistory() { Id=1, CustomerId=1, Text="bla" });
return c;
}
I'm stuck with regards to how to progress - my current thinking is that this could be a deserialization issue on the Silverlight side, when the object graph is deeper. This rationally doesn't make sense, but I can't think of anything else. I've confirmed that the transfer size and buffer size are big enough (2GB by default).
Any pointers would be appreciated.
Ahhhh the famous "Not Found" error, try to get details from that error using the tag in your web.config. That will create a log file providing details of the error.
The following link explains exaclty how to do it :
http://blogs.runatserver.com/lppinson/post/2010/04/15/Debugging-WCF-Web-Services.aspx