Web service Asynchronous call fails

Discussion in 'ASP .Net Web Services' started by anonymus, Jan 27, 2004.

  1. anonymus

    anonymus Guest

    Hi
    I created a webservice with a simple we method to increment a number passed from the client(a console app) .
    Then i call this web service method asynchronus mode from the client.
    I create a callback function and call EndXXX(XXX denotes the function name) in the callback function.
    But the function call never ends. means the web service is not working in async mode
    I have added the web refernce properly because i was able to succesfully call the same function in synchronous mode

    Where am i going wrong

    Thanks in advance
    Nirk
    anonymus, Jan 27, 2004
    #1
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  2. anonymus

    Trebek Guest

    The issue lies with your calling of the async webmethod, not the web service
    itself. To the web service, your proxy's call is treated as synchronous
    from its prospective. It doesn't know how you invoked the call. Why don't
    you post your asynchronous call in an example format and I'm sure we can
    help you. Are you calling the async method with waitHandles, callback
    functions...?

    EX:

    IAsync example using delegates -- for example SomeMethod returns int

    private void invokeMethod(string args){

    <proxy_class_instance>.BeginSomeMethod(new
    AsyncCallback(SomeMethod_Callback),null)

    }

    private void count_Complete(IAsyncResult ir)

    {

    int i = <proxy_class_instance>.EndSomeMethod(ir);

    Debug.WriteLine(i.ToString());

    }

    IAsync example using IAsyncResult in synchronous fashion

    private void invokeMethod(string args){

    IAsyncResult ir = <proxy_class_instance>.BeginSomeMethod(null,null)
    int i = <proxy_class_instance>.EndSomeMethod(ir);
    Debug.WriteLine(i.ToString());


    }

    There are other ways to call it as well (using waithandles,
    manualresetevents, etc..)but my guess would be to try one of these options.
    If you still have the same problem, just post the code.

    Alex

    "anonymus" <> wrote in message
    news:...
    > Hi
    > I created a webservice with a simple we method to increment a number

    passed from the client(a console app) .
    > Then i call this web service method asynchronus mode from the client.
    > I create a callback function and call EndXXX(XXX denotes the function

    name) in the callback function.
    > But the function call never ends. means the web service is not working in

    async mode
    > I have added the web refernce properly because i was able to succesfully

    call the same function in synchronous mode
    >
    > Where am i going wrong
    >
    > Thanks in advance
    > Nirk
    >
    >
    Trebek, Jan 27, 2004
    #2
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  3. anonymus

    nirk Guest

    Hi Trebek
    Please find the sample code as below.

    CLIENT CODE
    class Class1
    {
    /// <summary>
    /// The main entry point for the application.
    /// </summary>
    private static bool bEnd= false;


    public static void PrimeCallback(IAsyncResult arResult)
    {
    // Obtains the last parameter of the delegate call.

    Console.WriteLine ("Inside PrimeCallback");
    // get the "this" pointer that was passed...
    WSPrime wsp=(WSPrime)arResult.AsyncState;

    // call "EndPrime" and get the result..
    int iCount=wsp.EndPrime(arResult);

    /// show the result of the webservice call..
    Console.WriteLine("Async. WebService call found {0} primes.", iCount);

    // set flag so that application can terminate...
    bEnd=true;

    }
    [STAThread]
    static void Main(string[] args)
    {

    try
    {
    int intTemp;
    IAsyncResult ar;
    Console.WriteLine("Calling WebService Asynchronously...\n");
    AsyncCallback ascb = new AsyncCallback (Class1.PrimeCallback);
    //for (int i =2;i<=10;i++)
    {
    WSPrime wsp = new WSPrime();
    //intTemp = wsp.Prime (10);
    wsp.BeginPrime(10,ascb,wsp);

    }


    Console.WriteLine ("waiting for WebService");
    while(bEnd == false);
    Console.WriteLine ("Over" );
    Console.ReadLine ();
    }

    //
    // TODO: Add code to start application here
    //
    catch(System.Exception exception)
    {
    Console.WriteLine (exception.Message);
    }
    }


    };

    WEBSERVICE CODE
    using System.Web.Services;

    public class WSPrime : WebService
    {
    // This method returns the number of prime number lying between
    // 2 and num.
    [WebMethod]
    public int Prime(int num)
    {
    int iCount=0;
    for(int i=2;i<num;i++)
    {
    bool bPrime=true;
    for(int j=2;j<i;j++)
    {
    // is this number prime ?
    if (i%j==0)
    {
    // nope.. it isn't...
    bPrime=false;
    break;
    }
    }

    if (bPrime==true)
    iCount++;
    }

    // return the count..
    return iCount;
    }
    }

    I tried using Thread.Sleep() in 'While' loopin client code .As well as i tried to catch the error exception by placing a try/ catch to my callback method in client code but none of them helped me either
    nirk, Jan 28, 2004
    #3
  4. anonymus

    Trebek Guest

    Nirk,

    Due to async calls coming back on different thread pool threads, try taking
    the webservice call out of the 'Main' method and instead add it to some
    other method and see if the result is the same. Using your code, I had no
    trouble calling the WS method from another method of my instance class.

    HTH,
    Alex

    "nirk" <> wrote in message
    news:...
    > Hi Trebek
    > Please find the sample code as below.
    >
    > CLIENT CODE
    > class Class1
    > {
    > /// <summary>
    > /// The main entry point for the application.
    > /// </summary>
    > private static bool bEnd= false;
    >
    >
    > public static void PrimeCallback(IAsyncResult arResult)
    > {
    > // Obtains the last parameter of the delegate call.
    >
    > Console.WriteLine ("Inside PrimeCallback");
    > // get the "this" pointer that was passed...
    > WSPrime wsp=(WSPrime)arResult.AsyncState;
    >
    > // call "EndPrime" and get the result..
    > int iCount=wsp.EndPrime(arResult);
    >
    > /// show the result of the webservice call..
    > Console.WriteLine("Async. WebService call found {0} primes.", iCount);
    >
    > // set flag so that application can terminate...
    > bEnd=true;
    >
    > }
    > [STAThread]
    > static void Main(string[] args)
    > {
    >
    > try
    > {
    > int intTemp;
    > IAsyncResult ar;
    > Console.WriteLine("Calling WebService Asynchronously...\n");
    > AsyncCallback ascb = new AsyncCallback (Class1.PrimeCallback);
    > //for (int i =2;i<=10;i++)
    > {
    > WSPrime wsp = new WSPrime();
    > //intTemp = wsp.Prime (10);
    > wsp.BeginPrime(10,ascb,wsp);
    >
    > }
    >
    >
    > Console.WriteLine ("waiting for WebService");
    > while(bEnd == false);
    > Console.WriteLine ("Over" );
    > Console.ReadLine ();
    > }
    >
    > //
    > // TODO: Add code to start application here
    > //
    > catch(System.Exception exception)
    > {
    > Console.WriteLine (exception.Message);
    > }
    > }
    >
    >
    > };
    >
    > WEBSERVICE CODE
    > using System.Web.Services;
    >
    > public class WSPrime : WebService
    > {
    > // This method returns the number of prime number lying between
    > // 2 and num.
    > [WebMethod]
    > public int Prime(int num)
    > {
    > int iCount=0;
    > for(int i=2;i<num;i++)
    > {
    > bool bPrime=true;
    > for(int j=2;j<i;j++)
    > {
    > // is this number prime ?
    > if (i%j==0)
    > {
    > // nope.. it isn't...
    > bPrime=false;
    > break;
    > }
    > }
    >
    > if (bPrime==true)
    > iCount++;
    > }
    >
    > // return the count..
    > return iCount;
    > }
    > }
    >
    > I tried using Thread.Sleep() in 'While' loopin client code .As well as i

    tried to catch the error exception by placing a try/ catch to my callback
    method in client code but none of them helped me either
    >
    >
    >
    Trebek, Jan 28, 2004
    #4
  5. anonymus

    nirk Guest

    Hi Trebe
    Pls post yur client code i want to have a look to i

    Thanks in advanc
    Nirk
    nirk, Jan 29, 2004
    #5
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