Async call of WCF using Duplex Communication to get Database change - wpf

Question

I am implementing and WCF Async service using WsDualHttpBinding binding for duplex communication to get database changes.
I have implemented the Service but I dont know how to call it from Client application.
Here is the code.
The below code is WCF Service
[ServiceContract()]
public interface ICustomerService
{
[OperationContract(IsOneWay = true)]
void GetAllCustomer();
}
public interface ICustomerServiceCallback
{
[OperationContract(IsOneWay = true)]
void Callback(Customer[] customers);
}
[ServiceContract(Name = "ICustomerService",
CallbackContract = typeof(CustomerServiceLibrary.ICustomerServiceCallback),
SessionMode = SessionMode.Required)]
public interface ICustomerServiceAsync
{
[OperationContract(AsyncPattern = true)]
IAsyncResult BeginGetAllCustomer(AsyncCallback callback, object asyncState);
void EndGetAllCustomer(IAsyncResult result);
}
[DataContract]
public class Customer
{
[DataMember]
public string Name
{
get;
set;
}
}
}
public class CustomerService :ICustomerService,IDisposable
{
List<Customer> Customers = null;
ICustomerServiceCallback callback;
Customer customer = null;
string constr = "Data Source=.;Initial Catalog=WPFCache;Persist Security Info=True;User ID=sa;Password=Password$2";
public CustomerService()
{
callback = OperationContext.Current.GetCallbackChannel<ICustomerServiceCallback>();
SqlDependency.Start(constr);
}
public void GetAllCustomer()
{
using (SqlConnection con = new SqlConnection(constr))
{
using (SqlCommand cmd = new SqlCommand())
{
con.Open();
cmd.Connection = con;
cmd.CommandText = "GetHero";
cmd.CommandType = CommandType.StoredProcedure;
cmd.Notification = null;
// Create the associated SqlDependency
SqlDependency dep = new SqlDependency(cmd);
dep.OnChange += new OnChangeEventHandler(dep_OnChange);
SqlDataReader dr = cmd.ExecuteReader();
Customers = new List<Customer>();
while (dr.Read())
{
customer = new Customer();
customer.Name = dr.GetString(0);
Customers.Add(customer);
}
}
callback.Callback(Customers.ToArray());
}
}
void dep_OnChange(object sender, SqlNotificationEventArgs e)
{
try
{
if (e.Type == SqlNotificationType.Change)
{
GetAllCustomer();
}
}
catch (Exception ex)
{
throw ex;
}
}
public void Dispose()
{
SqlDependency.Stop(constr);
}
}
I have hosted this WCF Async Service as self hosting in a Console Application.
Here the hosting code
class Program
{
static void Main(string[] args)
{
StartService();
}
internal static ServiceHost myServiceHost = null;
internal static void StartService()
{
Uri httpbaseAddress = new Uri("http://localhost:8087/CustomerService/");
Uri[] baseAdresses = { httpbaseAddress };
myServiceHost = new ServiceHost(typeof(CustomerServiceLibrary.CustomerService));
myServiceHost.AddServiceEndpoint(typeof(CustomerServiceLibrary.ICustomerService), new WSDualHttpBinding(), httpbaseAddress);
ServiceDescription serviceDesciption = myServiceHost.Description;
foreach (ServiceEndpoint endpoint in serviceDesciption.Endpoints)
{
Console.WriteLine("Endpoint - address: {0}", endpoint.Address);
Console.WriteLine(" - binding name:\t\t{0}", endpoint.Binding.Name);
Console.WriteLine(" - contract name:\t\t{0}", endpoint.Contract.Name);
Console.WriteLine();
}
myServiceHost.Open();
Console.WriteLine("Press enter to stop.");
Console.ReadKey();
if (myServiceHost.State != CommunicationState.Closed)
myServiceHost.Close();
}
}
In client Application have crated a DuplexChannel factory instance
Here is the Code.
private void Window_Loaded(object sender, RoutedEventArgs e)
{
EndpointAddress address = new EndpointAddress(new Uri("http://localhost:8087/CustomerService"));
WSDualHttpBinding wsDualBinding = new WSDualHttpBinding();
DuplexChannelFactory<ICustomerServiceAsync> client = new DuplexChannelFactory<ICustomerServiceAsync>(new InstanceContext(this), wsDualBinding, address);
App.channel = client.CreateChannel();
}
Now My question is How I can call the
BeginGetAllCustomer
EndGetAllCustomer
Method of My service.
Help me.... A big thanks in Advance ...

Answer 1

You need:
InstanceContext instanceContext = new InstanceContext(YOUR_OBJECT_IMPLMENTS_CALLBACK);
and
using (App.channel as IDisposable)
{
App.channel.YOUR_METHOD_HERE();
}
from this example:
endPointAddr = "net.tcp://" + textBox2.Text + ":8000/FIXMarketDataHub";
NetTcpBinding tcpBinding = new NetTcpBinding();
tcpBinding.TransactionFlow = false;
tcpBinding.Security.Transport.ProtectionLevel = System.Net.Security.ProtectionLevel.EncryptAndSign;
tcpBinding.Security.Transport.ClientCredentialType = TcpClientCredentialType.Windows;
tcpBinding.Security.Mode = SecurityMode.None;
EndpointAddress endpointAddress = new EndpointAddress(endPointAddr);
Append("Attempt to connect to: " + endPointAddr);
InstanceContext instanceContext = new InstanceContext(??);
IMarketDataPub proxy = DuplexChannelFactory<IMarketDataPub>.CreateChannel(instanceContext,tcpBinding, endpointAddress);
using (proxy as IDisposable)
{
proxy.Subscribe();
Append("Subscribing to market data");
}
See also microsoft example