How to read Application log and filter it based on source in ASP.NET?

Question

In my application I want to read local system's application event log. Currently I am using the following code

public partial class AppLog : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            System.Diagnostics.EventLog logInfo = new System.Diagnostics.EventLog();
            logInfo.Log = "Application";
            logInfo.MachineName = ".";  // Local machine
            string strImage = "";  // Icon for the event
            Response.Write("<p>There are  " + logInfo.Entries.Count + " entries in the System event log.</p>");


            foreach (EventLogEntry entry in logInfo.Entries.Cast<EventLogEntry>().Reverse<EventLogEntry>())            
            {
                switch (entry.EntryType)
                {
                    case EventLogEntryType.Warning:
                        strImage = "images/icon_warning.PNG";
                        break;
                    case EventLogEntryType.Error:
                        strImage = "images/icon_error.PNG";
                        break;
                    default:
                        strImage = "images/icon_info.PNG";
                        break;
                }
                Response.Write("<img src=\"" + strImage + "\">&nbsp;|&nbsp;");
                Response.Write(entry.TimeGenerated.ToString() + "&nbsp;|&nbsp;");
                Response.Write(entry.Message.ToString() + "<br>\r\n");
            }
        }
    }
}

I want to show only the log created by ASP.NET.I know I can filter it within the for-each loop.But this takes lot of time as it needs to iterate through the whole application log.Is there any way to to filter it before it goes into any iteration??

====EDIT====

I got a way to make query,don't know whether it really improves the performance

    var result = (from EventLogEntry elog in logInfo.Entries
                  where (elog.Source.ToString().Equals("ASP.NET 2.0.50727.0"))
                  orderby elog.TimeGenerated descending
                  select elog).ToList();

and iterate through the result list.

Gotta give you props for your linq query there! Works fantastic for what I need! — ganders, Aug 28 '12 at 19:13

score 1 · Answer 1 · edited Oct 11 '19 at 06:38

1

var eventLog = new EventLog("Application");
eventLog.Entries
        .Cast<EventLogEntry>()
        .Select(e => e.Source == "yourFilter");

edited Oct 11 '19 at 06:38

h-rai

3,636
6
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answered Jan 21 '16 at 22:40

Andrew Rebane

199
3
12

score 0 · Answer 2 · answered Jul 10 '13 at 15:48

FYI: It's your reverse() that's causing the slowdown. Linq helps with the filtering as long as you don't reverse it afterwards.

I ended up doing this for my purposes:

for(int x = logInfo.Entries.Count-1; x >= 0; x--)
        {
          EventLogEntry entry = (EventLogEntry)logInfo.Entries[x]; ...

To explain a bit more, for every iteration of your loop, you're calling the reverse() which is slow and intensive. You might be able to speed it up if you reverse prior to the foreach loop.

score 0 · Accepted Answer · edited May 23 '17 at 12:23

0

See if these help

Read event log in C#

http://www.vinull.com/Post/2007/10/16/aspnet-working-with-the-event-log.aspx

edited May 23 '17 at 12:23

Community

1
1

answered Apr 19 '11 at 05:00

Subhash Dike

1,836
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37

How to read Application log and filter it based on source in ASP.NET?

3 Answers3