'SmtpPickupDirAppender' does not contain a definition for 'SmtpHost' and no accessible extension method 'SmtpHost' accepting a first argument

Question

I have this piece of code in .net framework class library project, I want to reuse it in.net standard class library project. It works as expected, but gives compilation error in .net standard project.

foreach (AppenderElement element in FX_CONNECT.EmailElement.Appenders)
{
    var smtpElement = (log4net.Appender.SmtpPickupDirAppender)AppLogger.Logger.Repository.GetAppenders().Where(appender => appender.Name.Equals(element.Name)).FirstOrDefault();
    if (smtpElement != null)
    {
        smtpElement.From = FX_CONNECT.EmailElement.From;
        smtpElement.To = FX_CONNECT.EmailElement.To;
        smtpElement.SmtpHost = FX_CONNECT.EmailElement.Server;
    }
}

Error for smtpElement.SmtpHost:

Error CS1061 'SmtpPickupDirAppender' does not contain a definition for 'SmtpHost' and no accessible extension method 'SmtpHost' accepting a first argument of type 'SmtpPickupDirAppender' could be found (are you missing a using directive or an assembly reference?)

log4net version in both application 2.0.8.

I searched on the internet but didn't get any clue how to solve this issue, please help.

I have gone through the log4net official site, It doesn't support .net standard as of now.

https://logging.apache.org/log4net/release/framework-support.html

So Is there any workaround to solve this?

Claudio Redi · Answer 1 · 2020-07-11T04:46:06.013

1

I'm confused about why you say the problem is related to .net standard. The documentation of SmtpPickupDirAppender says

/// The configuration for this appender is identical to that of the <c>SMTPAppender</c>,
/// except that instead of specifying the <c>SMTPAppender.SMTPHost</c> you specify 
/// <see cref="PickupDir"/>.

This appender does not work with a Smtp host but with a file system directory. You need to set PickupDir property.

Change SmtpPickupDirAppender by SmtpAppender in case you want to send emails for real or replace

smtpElement.SmtpHost = FX_CONNECT.EmailElement.Server;

by

smtpElement.PickupDir = "C:\YourPickUpDir";

in case you want to keep using that appender.

edited Jul 11 '20 at 04:46

answered Jul 11 '20 at 02:14

Claudio Redi

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Thank you, by the way in my case it should be the server address instead of path. Anyways I'll try and update – Vivek Nuna Jul 11 '20 at 02:30
It's not able to nd out `SMTPAppender ` – Vivek Nuna Jul 11 '20 at 04:35
@viveknuna: the name of the class is `SmtpAppender`. Just fixed it. – Claudio Redi Jul 11 '20 at 04:46
Its not even taking `SmtpAppender` – Vivek Nuna Jul 11 '20 at 04:49
1

`SmtpAppender` is indeed not supported in .net standard. [here](https://github.com/HatfieldConsultants/Log4Net.Core.CustomAppenders) you can find a .net standard compatible appender that you might be able to use as reference. I didn't test it myself though. – Claudio Redi Jul 11 '20 at 04:58

score 0 · Accepted Answer · answered Jul 11 '20 at 11:32

Thank you @Claudio Redi for your comment, It gave me the right direction to solve the issue.

I added the below class to my project and used the SMTPAppender class in place of log4net.Appender.SmtpPickupDirAppender in the line var smtpElement = (SMTPAppender)AppLogger.Logger.Repository.GetAppenders().Where(appender => appender.Name.Equals(element.Name)).FirstOrDefault(); and it's working as expected.

using log4net.Appender;
using log4net.Core;
using System.IO;
using System.Net.Mail;

namespace FxCore.Diagnostics.Components
{
    public class SMTPAppender : BufferingAppenderSkeleton
    {
        public string To { get; set; }
        public string From { get; set; }
        public string Subject { get; set; }
        public string SmtpHost { get; set; }
        public string Port { get; set; }

        protected void SendEmail(string messageBody)
        {
            SmtpClient client = new SmtpClient(SmtpHost);
            client.UseDefaultCredentials = false;
            client.Port = int.Parse(Port);
            using (MailMessage mailMessage = new MailMessage())
            {
                mailMessage.From = new MailAddress(From);
                mailMessage.To.Add(To);
                mailMessage.Body = messageBody;
                mailMessage.Subject = Subject;
                client.Send(mailMessage);
            }
        }

        protected override bool RequiresLayout => true;

        protected override void SendBuffer(LoggingEvent[] events)
        {
            StringWriter writer = new StringWriter(System.Globalization.CultureInfo.InvariantCulture);

            string t = Layout.Header;
            if (t != null)
            {
                writer.Write(t);
            }

            for (int i = 0; i < events.Length; i++)
            {
                // Render the event and append the text to the buffer
                RenderLoggingEvent(writer, events[i]);
            }

            t = Layout.Footer;
            if (t != null)
            {
                writer.Write(t);
            }

            SendEmail(writer.ToString());
        }
    }
}

'SmtpPickupDirAppender' does not contain a definition for 'SmtpHost' and no accessible extension method 'SmtpHost' accepting a first argument

2 Answers2