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How does Global.asax pick up exceptions from a C# web services method?

Posted on 2008-06-26
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Last Modified: 2012-05-05
I have a simple class (you can see it below) but it is a web services method and it does a division by zero and throws an exception.

I have a Global.asax that should get the error message?
How does Global.asax know to catch the error message? it isn't working for me. I put a breakpoint in my method

INSIDE Global.asax

protected virtual void Application_Error(Object sender, EventArgs e)
{
    BREAK POINT HERE but it never gets hit.
}
public class Birthday : System.Web.Services.WebService
    {
 
        [WebMethod]
        public int divideByZERO(int pInt, int pIntZero)
        {
            try
            {
                return pInt / pIntZero;
            }
            catch (Exception ex)
            {
                
                //Console.WriteLine("EXCEPTION");
                throw ex;
            }
            return 42;
        }
}

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0
Comment
Question by:alexmac05
[X]
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13 Comments
 
LVL 23

Expert Comment

by:Jens Fiederer
ID: 21878785
Are you using the Global.asax for the service, or the Global.asax for the consumer of the service?
0
 
LVL 33

Assisted Solution

by:raterus
raterus earned 500 total points
ID: 21878795
Try making your declaration in Global.asax look like this


    void Application_Error(object sender, EventArgs e) 
    { 
        // Code that runs when an unhandled error occurs
 
    }

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0
 

Author Comment

by:alexmac05
ID: 21879103
It is for the service.

also, changing the function by removing protected and void didn't work.

Thanks,
alex
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LVL 33

Assisted Solution

by:raterus
raterus earned 500 total points
ID: 21879114
Post the entire code of Global.asax, and tell me where it's located in your application?  Have you tried putting code in other events and verified they work?
0
 

Author Comment

by:alexmac05
ID: 21879238
I am a newbie to this. I'm used to coding but not .net web apps.

I haven't tried any other events.

What should I be googling to read about this? Just Global.asax events?

I have uploaded a picture of where it is located in the project
namespace BirthDayWS
{
    public class Global : System.Web.HttpApplication
    {
 
        protected void Application_Start(object sender, EventArgs e)
        {
 
        }
 
        protected void Application_End(object sender, EventArgs e)
        {
 
        }
 
        void Application_Error(Object sender, EventArgs e)
        {
            string errMsg, userText, pageData, versionInfo, eSource = "", eDetails = "", eStack = "";
            Exception outerE = null, innerE = null, testE;
 
            AssemblyName currentAss;
 
            try
            {
                outerE = Server.GetLastError();
 
                HttpException httpException = outerE as HttpException;
 
                if (httpException != null)
                {
                    if (httpException.GetHttpCode() == 500)
                    {
                        
                    }
 
                    Exception innerException = httpException.InnerException;
 
                    if (innerException != null)
                    {
                        if (innerException.Message == "Maximum request length exceeded.")
                            return;
                    }
 
 
                }
                
 
            }
            catch (Exception ie)
            {
                eSource = "<b>BABY JESUS</b>" + ie.Message + "</b>";
 
 
 
            }
            try
            {
                currentAss = Assembly.GetExecutingAssembly().GetName();
                versionInfo = "<b>Version Information:</b> " + currentAss.Name + " Version: " + currentAss.Version.ToString();
 
            }
            catch (Exception ie)
            {
                versionInfo = ie.Message + " Hello alex";
            }
 
 
        }
    }
}

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LocationOfGlobalASAXFile.bmp
0
 
LVL 6

Expert Comment

by:cottsak
ID: 21880718
put a breakpoint on the 1st brace "{" in the Application_Error function.
then get rid of the try/catch in the WebMethod... it may be that the exception was 'caught' then re-thrown thats bypassing the global handler.
0
 
LVL 33

Assisted Solution

by:raterus
raterus earned 500 total points
ID: 21883118
Why did you add a Namespace (BirthDayWS) to this Global class?  I think this needs to be removed, because you are probably pushing this class into a namespace that asp.net doesn't know how to find and thus throw your events into.
0
 

Author Comment

by:alexmac05
ID: 21884205
THe namespace was created by default when I created the file. It has to be there, it is the namespace of the application.

Console.WriteLine("Application_Start was hit"); that I will see these lines if the callbacks are fired?



 protected void Application_Start(object sender, EventArgs e)
        {
                Console.WriteLine("Application_Start was hit");
        }
 
        protected void Application_End(object sender, EventArgs e)
        {
                    Console.WriteLine("Application_Start was hit");
        }

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LVL 33

Accepted Solution

by:
raterus earned 500 total points
ID: 21884278
No, there is no ASP.Net console to view.  I'd output to a file, that's pretty much guaranteed.  Just remember to write to a file you have permissions to (like right next to the global.asax)!

        StreamWriter output = new StreamWriter("c:\\my\\www\\root\\log.txt",true);
        output.WriteLine("Doing something at: " & DateTime.Now.ToString());
        output.Close();

0
 

Author Comment

by:alexmac05
ID: 21886212
There are two files associated with this file.

1. Global.asax

2. Global.asax.cs

My question now is where should I write to a file? Global.asax.cs?

Also, I wonder if the Global.asax needs more code in it? I only see one line in it:

<%@ Application Codebehind="Global.asax.cs" Inherits="BirthDayWS.Global" Language="C#" %>

but in searching the net some files seem to look like the attached bit map

IsThisWhatMineShouldLookLIke.jpg
0
 

Author Closing Comment

by:alexmac05
ID: 31471164
Thanks a lot for your help.
0
 

Author Comment

by:alexmac05
ID: 21886430
Problem: How do you get callbacks to fire in the Global.aspx.cs code behind file in VS2005 if theyre not firing automatically?

Answer:

So, as we know, the Global.aspx file is two files

1.      Global.aspx  the script
2.      Global.aspx.cs  the code behind file

Using Visual Studio 2005, one must manually create this file.  

Then one must go to the script part and add the callbacks manually.
<%@ Application Codebehind="Global.asax.cs" Inherits="BirthDayWS.Global" Language="C#" %>

<script RunAt="server">
   
    void Application_Start(Object sender, EventArgs e)
    {
        //Code that runs on applicaton startup
       
    }


    void Application_End(Object sender, EventArgs e)
    {

    }

    void Application_Error(Object sender, EventArgs e)
    {

    }

    void Session_End(Object sender, EventArgs e)
    {

    }
   
   
</script>


If the Global.aspx file has these callbacks just as I have listed them here (BLANK) then this causes the callbacks to fire such that inside the Global.asax.cs file you can code whatever you want or set breakpoints.

Yeah.


Cheers,
Alex



 
0
 

Expert Comment

by:Metafuse
ID: 22674119
The Application_OnError in the Global.asax works for ASP.NET but does not work for web services.   The reason for this is that the HTTP handler for XML Web services consumes any exception that occurs while an XML Web service is executing and turns it into a SOAP fault prior to the Application_Error event is called.

To create global exception handling for your web services you have to build a SOAP extension. The SOAP extension can check for the existence of an exception in the ProcessMessage method and will handle the global error handling in a similar way that the ASP.NET Application_OnError does.

Obviously

public class SoapExceptionHandler : System.Web.Services.Protocols.SoapExtension 
{ 
      public override void ProcessMessage(System.Web.Services.Protocols.SoapMessage message) 
     { 
         if (message.Stage == SoapMessageStage.AfterSerialize) 
         { 
             if (message.Exception != null) 
             { 
                   //log your error here
             } 
        } 
    } 
    public override object GetInitializer(Type serviceType) 
    { 
        return null; 
    } 
     public override object GetInitializer(LogicalMethodInfo methodInfo, SoapExtensionAttribute attribute) 
    { 
        return null; 
    } 
    public override void Initialize(object initializer)
    { 
    } 
}

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