sending mails with SmtpClient - asp.net

Question

This is my first time to write a program that sends mails. I don't know what to put in the SMTP client constructor :
SmtpClient client = new SmtpClient(????);
Can anybody help?

Answer 1

Always consult the documentation. The SmptClient has three constructors.
SmtpClient()
SmtpClient(String)
SmtpClient(String, Int32)
If you choose the last one, then your code would look like the following, for gmail:
SmtpClient client = new SmtpClient("smtp.gmail.com", 587);
You could also use the first constructor and set properties instead.
SmtpClient smtp = new SmtpClient();
smtp.Port = 587;
smtp.EnableSsl = true;
smtp.Credentials = new NetworkCredential("<email_from>", "password");
smtp.Host = "smtp.gmail.com";

Answer 2

This is your host and optional port.
For example:
SmtpClient client = new SmtpClient("mail.domain.com", 123);
For more information, you should read the MSDN documentation for this class:
http://msdn.microsoft.com/en-us/library/system.net.mail.smtpclient.aspx

Answer 3

You can specify the SMTP host and port in code as others have suggested.
But if you're always using the same host and port, it's probably easier and more flexible to use the default SmtpClient constructor, and specify the host and port in the <smtp> element of your application configuration file:
using(var smtpClient = new SmtpClient())
{
...
}
<system.net>
<mailSettings>
<smtp deliveryMethod="network" from="ben#contoso.com">
<network
host="localhost"
port="25"
defaultCredentials="true"
/>
</smtp>
</mailSettings>
<system.net>
One advantage of this is that you can use a different configuration in your development/test environment, such as the one below, which will avoid sending unwanted mails to your system's mail recipients without any code changes.
<smtp deliveryMethod="SpecifiedPickupDirectory" from="ben#contoso.com">
<network host="localhost"/>
<specifiedPickupDirectory pickupDirectoryLocation="C:\temp\mail\"/>
</smtp>

Answer 4

public SmtpClient(
string host,
int port
)
Basically you need to pass host-name and port-number
Please read more about SmtpClient Constructor

Answer 5

This is slightly off-topic, but supports a best practices approach relating to modern email delivery over SMTP...
I would recommend always using a service that supports TLS over SSL as it provides more secure transmissions.
If you're unfamiliar with TLS, #gideon provided an example of using TLS with GMail and here is an article which supports this approach: C# ASP.NET Send Email via TLS