Question

I am writing a test WCF server with a method to add 2 numbers and wait a configurable number of milliseconds.

I have written a wcf client. When I open two instances of this client – on clientA the wait value is 50 seconds and on the other clientB the wait is 0 seconds. I expect that when client A is running (long process) client B will get its response immediately.

It is however not working. I have been following this tutorial WCF Concurrency

Why is it not working for me?

WCF Service

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Serialization;
using System.ServiceModel;
using System.Text;


namespace WCFService
{
    //[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall,ConcurrencyMode = ConcurrencyMode.Multiple,UseSynchronizationContext = true)]
    //[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall,ConcurrencyMode = ConcurrencyMode.Single)] 
    //[ServiceBehavior(ConcurrencyMode = ConcurrencyMode.Multiple)]
    //[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession,ConcurrencyMode = ConcurrencyMode.Multiple)]
    //[ServiceBehavior(InstanceContextMode = InstanceContextMode.PerCall, ConcurrencyMode = ConcurrencyMode.Multiple)]
    [ServiceBehavior(InstanceContextMode = InstanceContextMode.PerSession,ConcurrencyMode = ConcurrencyMode.Multiple)]
    public class WCFJobsLibrary : IWCFJobsLibrary
    {

        public ReturnClass AddNumbers(int FirstNumber, int SecondNumber, int Delay) //Add two numbers and wait a predefined interval
        {
            ReturnClass myReturnClass = new ReturnClass(-1, null, null, 0);
            try
            {             

                myReturnClass.ErrorCode = 1;
                myReturnClass.Result = FirstNumber + SecondNumber;
                System.Threading.Thread.Sleep(Delay); // Wait
                return myReturnClass;

            }
            catch (Exception ex)
            {              
                myReturnClass.ErrorCode = -1;
                myReturnClass.ErrorMessage = ex.ToString();
                return myReturnClass;
            }

        }

    }
}

WCF Client

try
            {

                radTextBoxResult.Text = ""; // Reset Result
                ServiceReference1.WCFJobsLibraryClient Client = new ServiceReference1.WCFJobsLibraryClient();
                Client.Endpoint.Address = new System.ServiceModel.EndpointAddress(radTextBoxbaseAddress.Text);
                WCFClient.ServiceReference1.ReturnClass AddNumbers_Result;
                AddNumbers_Result = Client.AddNumbers(int.Parse(radTextBoxFirstNumber.Text), int.Parse(radTextBoxSecondNumber.Text), int.Parse(radTextBoxDelay.Text));


                if (AddNumbers_Result.ErrorCode < 0)
                {
                    // If exception happens, it will be returned here
                    MessageBox.Show(AddNumbers_Result.ErrorCode.ToString() + " " + AddNumbers_Result.ErrorMessage + " " + AddNumbers_Result.ExMessage);
                }

                else
                {

                    radTextBoxResult.Text = AddNumbers_Result.Result.ToString();

                }

            }

            catch (Exception ex)
            {

                MessageBox.Show(ex.Message.ToString());

            }

App.Config

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <system.serviceModel>
        <behaviors>
            <serviceBehaviors>
                <behavior name="">
                    <serviceMetadata httpGetEnabled="true" />
                    <serviceDebug includeExceptionDetailInFaults="false" />
                  <serviceThrottling maxConcurrentCalls="16" maxConcurrentInstances="2147483647" maxConcurrentSessions="10" />
                </behavior>
            </serviceBehaviors>
        </behaviors>
        <services>
            <service name="WCFService.WCFJobsLibrary">
                <endpoint address="" binding="wsHttpBinding" contract="WCFService.IWCFJobsLibrary">
                    <identity>
                        <dns value="localhost" />
                    </identity>
                </endpoint>
                <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" />
                <host>
                    <baseAddresses>
                        <add baseAddress="http://localhost:8732/Design_Time_Addresses/WCFService/WCFJobsLibrary/" />
                    </baseAddresses>
                </host>
            </service>
        </services>
    </system.serviceModel>
</configuration>

Answer 1

the problem was that i was starting the service in a winform application on the main thread. You need to start WCF on a seperate thread as illustrated below.

C# Code

private void radButtonStartWCFService_Click(object sender, EventArgs e)
{
    try
    {
        Thread Trd = new Thread(() => StartWCFServer());
        Trd.IsBackground = true;
        Trd.Start();

        radButtonStartWCFService.Enabled = false;
        radButtonStartWCFService.Text = "WCF Server Started";

    }

    catch(Exception ex)
    {
        MessageBox.Show(ex.Message.ToString());
    }
}


private void StartWCFServer()
{

    try
    {
        sHost = new ServiceHost(typeof(WCFService.WCFJobsLibrary));
        sHost.Open();

    }

    catch (Exception ex)
    {

        MessageBox.Show(ex.Message.ToString());

    }
}