Email not sent until application closes

Question

I have an application that uses SmtpClient to send E-Mail, but the E-Mails are not sent until the application closes. I have searched and searched to find a solution to the problem, but I am not able to find one.

The system does have Symantec anti-virus installed, which could possibly be the problem.

Does anybody have a solution to this problem?

Here is the code I am using.

public class EMail
{
    private string server;
    public string Server {get{return this.server;}set{this.server = value;}}
    private string to;
    public string To {get{return this.to;}set{this.to = value;}}
    private string from;
    public string From {get{return this.from;}set{this.from = value;}}
    private string subject;
    public string Subject {get{return this.subject;}set{this.subject = value;}}
    private string body;
    public string Body {get{return this.body;}set{this.body = value;}}

    public EMail()
    {}
    public EMail(string _server, string _to, string _from, string _subject, string _body)
    {
        this.Server = _server;
        this.To = _to;
        this.From = _from;
        this.Subject = _subject;
        this.Body = _body;
    }   

    public void Send()
    {
        using(System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(this.From, this.To, this.Subject, this.Body))
        {        
            message.IsBodyHtml = true;
            System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient(this.Server);
            client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;
            //I have tried this, but it still does not work.
            //client.ServicePoint.ConnectionLeaseTimeout = 0;
            try 
            {
                client.Send(message);
            }  
            catch(System.Exception ex) 
            {
                System.Windows.Forms.MessageBox.Show(ex.ToString());              
            }
        }
    }
}

Edit:

It turns out the email does eventually send after 2-3 minutes. It seems as though it is being queued by the exchange server, or the SmtpClient connection eventually times out and is closed by the server.

Edit:

I have tried.

client.ServicePoint.ConnectionLeaseTimeout = 1;
client.ServicePoint.MaxIdleTime = 1;

Answer 1

A possible cause is that the connection is being kept open. Try closing the connection at the end of the Send method and see if that works.

Answer 2

I am betting you have Norton Antivirus installed. This seems to be a known issue with Norton Antivirus. You can fix this by opening Norton antivirus and disabling the email tools. Let me know if that works for you.

Answer 3

Also, for any disposable types like System.Net.Mail.MailMessage you should used a "using" block:

public void Send() 
{ 
    using (System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(this.From, this.To, this.Subject, this.Body))
    {
        message.IsBodyHtml = true; 
        System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient(this.Server); 
        client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network; 
        try  
        { 
            client.Send(message); 
        }   
        catch(System.Exception ex)  
        { 
            System.Windows.Forms.MessageBox.Show(ex.ToString());               
        }
    } 
} 

Answer 4

System.Net.Mail.MailMessage and System.Net.Mail.SmtpClient both implement IDisposable, which means that you need to call Dispose on them after you're done. IE:

using (System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(this.From, this.To, this.Subject, this.Body))
{
    message.IsBodyHtml = true; 
    using(System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient(this.Server))
    {
        client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network; 
        try  
        { 
            client.Send(message); 
        }   
        catch(System.Exception ex)  
        { 
            System.Windows.Forms.MessageBox.Show(ex.ToString());               
        }
    }
} 

Answer 5

ok Tester...If you want to get around the Norton Issue, its pretty simple. Add the following line:

message.EnableSsl = true;

This will cause the smtp client to encrypt your connection, thus sending it on a different port then what norton monitors. See if that works!

Answer 6

I finally; after all the help from StackOverflow and other various research sources, have found the solution. By setting System.Net.ServicePointManager.MaxServicePointIdleTime = 1, the mail is sent immediately.

Here is the final code.

public class EMail
{
    private string server;
    public string Server {get{return this.server;}set{this.server = value;}}
    private string to;
    public string To {get{return this.to;}set{this.to = value;}}
    private string from;
    public string From {get{return this.from;}set{this.from = value;}}
    private string subject;
    public string Subject {get{return this.subject;}set{this.subject = value;}}
    private string body;
    public string Body {get{return this.body;}set{this.body = value;}}

    public EMail()
    {}
    public EMail(string _server, string _to, string _from, string _subject, string _body)
    {
        this.Server = _server;
        this.To = _to;
        this.From = _from;
        this.Subject = _subject;
        this.Body = _body;
    }   

    public void Send()
    {
        using(System.Net.Mail.MailMessage message = new System.Net.Mail.MailMessage(this.From, this.To, this.Subject, this.Body))
        {        
            message.IsBodyHtml = true;
            System.Net.Mail.SmtpClient client = new System.Net.Mail.SmtpClient(this.Server);
            client.DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network;

            int temp = System.Net.ServicePointManager.MaxServicePointIdleTime; //<- Store the original value.
            System.Net.ServicePointManager.MaxServicePointIdleTime = 1; //<- Change the idle time to 1.

            try 
            {
                client.Send(message);
            }  
            catch(System.Exception ex) 
            {
                System.Windows.Forms.MessageBox.Show(ex.ToString());              
            }
            finally
            {
                System.Net.ServicePointManager.MaxServicePointIdleTime = temp; //<- Set the idle time back to what it was.
            }
        }
    }
}

Thank you all for your help! Especially icemanind.