Error Handling: Catching Errors With ASP.Net and C# (Part 3)

Error Handling: Catching Errors With ASP.Net and C# (Part 3)

by: Wujen

Error Logging to the Windows Error Log

The namespace that you would use for this is System.Diagnostics and that would be added on the top of the page:

<%@ Import Namespace="System.Diagnostics"%>

The class EventLog will allow you to read and write to the event log; as well, as create a new one.

First of all you would need to create a new log that you could write in it. It being a specify event source.

The CreateEventSource() method can be use to create both a source and a log.

So here is a basic sample how to do it: (entry2log.aspx)

<%@ Import Namespace="System.Diagnostics"%>

<script language="c#" runat="server" >

   void Entry2Log()

   {

     int [] array = new int[12]

     for( int intCounter=0; intCounter <= 12;intCounter++)

     {

       array[intCounter] = intCounter;

       Response.Write("The value of this counter is:" 
                + intCounter + "<br />");

      }

   }

 void Page_Error(object sender,  EventsArgs e)

  {

    string errorMessage = "Error occurred" + Server.GetLastError();

    Server.ClearError();

    string LogName = "MyAppLog";

    string SourceName = "MyAppSource";

    if (!(EventLog.SourceExists(SourceName));

    {

        EventLog.CreateEventSource(SourceName, LogName);

     }

   EventLog MyLog = new EventLog();

   MyLog.Source = SourceName;

MyLog.WriteEntry(errorMessage, EventLogEntryType.Error);

}

</script>

<%

Entry2Log

%>

This code is not that interesting on the front end at all. The points of interest are with in your EventViewer; where your error logging has taken place. To open your event viewer, click start button, then select Setting; click control panel; double click administrative tools; then double click event viewer.

From there, you will see MyAppLog under the Name column. If you click on this; you will see the custom error that the aspx page created. Now if you click on the error it self; then you would see the full details of this error.

Alternatively, we could do all this in the Application_Error() part of the global.asax page. Doing this would make a master log of all the errors throughout the application.

Error Logging to the Webmaster/Administrator via Email

This part would use System.Web.Mail instead of System.Diagnostics.

So by using the code above; we will just alter a little bit of it and rename it to SendEmailTest.aspx:

<%@ Import Namespace = "System.Web.Mail" %>

<script language="c#" runat="server">

 void sendMailTest()

    {

     int [] array = new int[12]

     for( int intCounter=0; intCounter <= 12;intCounter++)

     {

       array[intCounter] = intCounter;

       Response.Write("The value of this counter is:" 
                            + intCounter + "<br />");

      }

   }

 void Page_Error(object sender, EventArgs e)

 string errorMessage = "Error occurred" + Server.GetLastError();

 Server.ClearError();

 MailMessage newMail = new MailMessage();

 newMail.From = "x@y.com"; // whatever your address needs are

 newMail.To = "z@y.com"; // whatever your address needs are

 newMail.Subject = "This error has occurred"

 newMail.Body =  errorMessage;

 SmtpMail.Send(newMail);

}

</script>

<%

 sendMailTest();

%>