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Raising Custom ASP.NET Health Monitoring Events Example

The example in this topic demonstrates how to implement an IHttpModule module that can raise a custom ASP.NET health monitoring event. For details about how to use this example, see How to: Implement and Raise Custom ASP.NET Health Monitoring Events.

Example

The following code example shows how to derive from the WebRequestEvent class to create a custom ASP.NET health monitoring event. For instructional purposes, the code is included in an HTTP module implementation that raises the custom event. Alternatively, you can raise the custom event from another ASP.NET page or assembly. Unlike built-in ASP.NET health monitoring events, custom events must be explicitly raised.

using System;
using System.Web;
using System.Web.Management;
using System.Web.UI;
using System.Web.UI.WebControls;


namespace Samples.AspNet.Management
{

    public class CustomWebEvents : Page, IHttpModule
    {

        public override void Dispose()
        {
        }

        // Add event handlers to the HttpApplication.
        public new void Init(HttpApplication httpApp)
        {
            httpApp.BeginRequest +=
                new EventHandler(OnBeginRequest);

            httpApp.EndRequest +=
                new EventHandler(OnEndRequest);

        }

        // Issues a custom begin request event.
        public void OnBeginRequest(Object sender, EventArgs e)
        {

            HttpApplication httpApp = sender as HttpApplication;

            try
            {
                // Make sure to be outside the forbidden range.
                System.Int32 myCode = WebEventCodes.WebExtendedBase + 30;
                SampleWebRequestEvent swre =
                  new SampleWebRequestEvent(
                  "SampleWebRequestEvent Start", this, myCode);
                // Raise the event.
                swre.Raise();
            }
            catch (Exception ex)
            {
                httpApp.Context.Response.Output.WriteLine(
                    ex.ToString());
            }

        }

        // Issues a custom end request event.
        public void OnEndRequest(Object sender, EventArgs e)
        {
            HttpApplication httpApp = sender as HttpApplication;

            try
            {
                // Make sure to be outside the forbidden range.
                System.Int32 myCode = WebEventCodes.WebExtendedBase + 40;
                SampleWebRequestEvent swre =
                  new SampleWebRequestEvent(
                  "SampleWebRequestEvent End", this, myCode);
                // Raise the event.
                swre.Raise();
            }
            catch (Exception ex)
            {
                httpApp.Context.Response.Output.WriteLine(
                    ex.ToString());
            }

        }
    }
    public class SampleWebRequestEvent : System.Web.Management.WebRequestEvent
    {
        private string customCreatedMsg;
        private string customRaisedMsg;

        // Invoked in case of events identified only by their event code.
        public SampleWebRequestEvent(
            string msg,
            object eventSource,
            int eventCode)
            :
            base(msg, eventSource, eventCode)
        {
            // Perform custom initialization.
            customCreatedMsg = string.Format("Event created at: {0}",
                EventTime.ToString());
        }

        // Invoked in case of events identified by their event code and 
        // related event detailed code.
        public SampleWebRequestEvent(
            string msg,
            object eventSource,
            int eventCode,
            int eventDetailCode)
            :
            base(msg, eventSource, eventCode, eventDetailCode)
        {
            // Perform custom initialization.
            customCreatedMsg = string.Format("Event created at: {0}",
                EventTime.ToString());

        }

        // Raises the SampleWebRequestEvent.
        public override void Raise()
        {
            // Perform custom processing.
            customRaisedMsg = string.Format("Event raised at: {0}",
                EventTime.ToString());

            // Raise the event.
            base.Raise();
        }

        //Formats Web request event information.
        public override void FormatCustomEventDetails(
            WebEventFormatter formatter)
        {
            // Add custom data.
            formatter.AppendLine("");

            formatter.IndentationLevel += 1;
            formatter.AppendLine("* Custom Request Information Start *");

            // Display custom event timing.
            formatter.AppendLine(customCreatedMsg);
            formatter.AppendLine(customRaisedMsg);

            formatter.AppendLine("* Custom Request Information End *");

            formatter.IndentationLevel -= 1;
        }
    }
}

See Also

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