Scenario One:  Generate an email alert when an error occurs

using System;
using System.Collections.Generic;
using System.Net.Mail;
using System.Text;
using System.Threading;
using Gibraltar.Agent.Data;

private void Log_MessageAlertSendEmail(object sender, LogMessageAlertEventArgs e)
{
    //if we had an error or critical we want to send
    if (e.TopSeverity <= LogMessageSeverity.Error) //numeric values DROP for more severe enum values
    {
        //get the set of messages that are the "worst" in this event.
        List<ILogMessage> badMessages = new List<ILogMessage>();
        foreach (ILogMessage message in e.Messages)
        {
            if (message.Severity == e.TopSeverity)
            {
                badMessages.Add(message);
            }
        }
        //now make us an email message describing these guys
        string messageBody = FormatMessageBody(badMessages);
        string subject = string.Format("{0} {1}: {2}", Log.SessionSummary.Application,
            e.TopSeverity.ToString().ToUpper(), badMessages[0].Caption);
        //and for safety's sake lets keep our subject from being crazy long.
        if (subject.Length > 120)
        {
            subject = subject.Substring(0, 120) + "...";
        }
        //now that we've done all of that, lets send our message using the Agent's email config
        using (MailMessage message = new MailMessage())
        {
            message.Subject = subject;
            message.Body = messageBody;
            message.Priority = MailPriority.High;
            //now send our email!  I'm not bothering to catch exceptions since the Agent handles that nicely for us
            Log.SendMessage(message); //synchronous OK because we're already async from the flow of logging.
        }
        //and lets make sure we don't send again for at least a few minutes
        //to ensure we don't flood in the event of a storm of errors.
        e.MinimumDelay = new TimeSpan(0, 5, 0); //5 minutes
    }
}

private string FormatMessageBody(List<ILogMessage> messages)
{
    StringBuilder messageBody = new StringBuilder(1024);
    //we write out more detail about the first item, then just summarize.
    ILogMessage firstMessage = messages[0];
    messageBody.AppendFormat("Timestamp: {0:g}\r\n", firstMessage.Timestamp);
    messageBody.AppendFormat("Category:  {0}\r\n", firstMessage.CategoryName);
    messageBody.AppendFormat("Class:     {0}\r\n------------------------------\r\n", firstMessage.ClassName);
    messageBody.AppendFormat("{0}\r\n", firstMessage.Caption);
    messageBody.AppendFormat("{0}\r\n\r\n", firstMessage.Description);
    //report any exceptions on this first object.
    IExceptionInfo currentException = firstMessage.Exception;
    if (currentException != null)
    {
        messageBody.Append("Exceptions:\r\n");
        while (currentException != null)
        {
            messageBody.AppendFormat("{0}: {1}\r\n\r\n", currentException.TypeName, currentException.Message);
            //Each outer exception can point to an inner exception, we get null when there are no more.
            currentException = currentException.InnerException;
        }
    }
    //summarize the rest of the messages
    if (messages.Count > 1)
    {
        messageBody.AppendFormat("Other {0}s:\r\n", firstMessage.Severity);
        for (int curMessageIndex = 1; curMessageIndex < messages.Count; curMessageIndex++)
        {
            ILogMessage currentMessage = messages[curMessageIndex];
            messageBody.AppendFormat("------------------------------\r\nMessage {0} of {1}: {2}: {3}\r\n\r\n",
                curMessageIndex, messages.Count, currentMessage.Severity, currentMessage.Caption);
        }
    }
    return messageBody.ToString();
}