When to call proxy's CloseAsync

Question

My Silverlight application uses a WCF proxy generated by adding a service reference. When do I have to close the proxy?
Is it safe to close it right after calling the service, before the asynchronous reponse arrives?

private void proxy_GetUserCompleted(object sender, GetUserCompletedEventArgs e)
{
}

Proxy proxy = new Proxy();
proxy.GetUserCompleted += new EventHandler<GetUserCompletedEventArgs>(proxy_GetUserCompleted);
proxy.GetUserAsync();
proxy.CloseAsync();

I can't find useful documentation or samples on the internet.
Thanks in advance!

Answer 1

Greetings,

Link is given below.

Hook into WCF proxy's generic begin and end operationRSS

• http://forums.silverlight.net/forums/p/141648/317738.aspx#317738

Service-Driven Apps With Silverlight 2 And WCF - Kindly look into this article.

• http://msdn.microsoft.com/en-us/magazine/cc794260.aspx

Hope this helps.

Take Care

PL

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Helping People To Solve Technical Problems

Answer 2

Thanks for your response. I appreciate it.
However, the first link references a thread that was started by myself ;-)
The second link doesn't mention the close in case of asynchronous communication.

Answer 3

You should close your proxy when you don't expect further communication with the service.
This includes making sure you got all the response for the requests you made.

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Christopher Scrosati, Software Design Engineer, WCF Silverlight, Microsoft Corp.

Answer 4

Thanks for your response.

I don't expect further communication with the service.
I prefer to call CloseAsync right after calling the service method instead of calling it when receiving the asynchronous response.
Is it safe to call CloseAsync right after calling the service, before the asynchronous reponse arrives, like the following example?

Proxy proxy = new Proxy();
proxy.GetUserCompleted += new EventHandler<GetUserCompletedEventArgs>(proxy_GetUserCompleted);
proxy.GetUserAsync();
proxy.CloseAsync();

Michel Miranda

Answer 5

Hi Michel,

By disassembling the RequestChannel, I found that it has a state check on BeginRequest, but doesn't have in EndRequest method, which implys that regardless the async call complete time, just call close after all service call will be OK.

With my little experiment, I found it work as we expected

service

    [ServiceContract(Namespace = "")]
    [AspNetCompatibilityRequirements(RequirementsMode = AspNetCompatibilityRequirementsMode.Allowed)]
    public class Service1
    {
        [OperationContract]
        public int DoWork(int second)
        {
            Thread.Sleep(TimeSpan.FromSeconds(second));
            return second;
        }
    }

client

        private void Button_Click(object sender, RoutedEventArgs e)
        {
            Service1Client sc1 = new Service1Client();
            sc1.DoWorkCompleted += new EventHandler<DoWorkCompletedEventArgs>(sc1_DoWorkCompleted);
            sc1.CloseCompleted += new EventHandler<System.ComponentModel.AsyncCompletedEventArgs>(sc1_CloseCompleted);
            
            sc1.DoWorkAsync(10);
            sc1.DoWorkAsync(2);
            sc1.CloseAsync();
        }

        void sc1_CloseCompleted(object sender, System.ComponentModel.AsyncCompletedEventArgs e)
        {
            if (e.Error != null)
                MessageBox.Show(e.Error.Message);
            else
                MessageBox.Show("Closed");
        }

        void sc1_DoWorkCompleted(object sender, DoWorkCompletedEventArgs e)
        {
            if (e.Error != null)
                MessageBox.Show(e.Error.Message);
            else
                MessageBox.Show(e.Result.ToString());
        }

So, I would say you can call CloseAsync just after all service call.

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Mog Liang

Answer 6

Hi Mog Liang,

Thanks a lot! This is realy useful.

I need to hook into the OpenCompleted and CloseCompleted events to show a progress bar when the application is waiting for a response from the service.
My CloseCompleted event handler works fine, but my OpenCompleted event handler doesn't get called. Strange.

As a workaround I hook into the Opened and Closed events of the ClientBase's InnerChannel property. Now both event handlers are being called.
Maybe you know why the OpenCompleted event handler doesn't get called.

Michel