非同期でUnityからメール(GMail)を送信する. 場合によってはGMailのセキュリティ設定で、 安全性の低いアプリのアクセスを オン にしなければならない. https://www.google.com/settings/security/lesssecureapps

AsyncMailSender.cs

using UnityEngine;
using System.Collections;

public class AsyncMailSender : MonoBehaviour {
	
	public string MailFromAddress = "from@gmail.com";
	public string MailHost        = "smtp.gmail.com";
	public int    MailPort        = 587;
	public string MailPassword    = "frompassword";
	public string MailToAddress   = "to@gmail.com";
	public string MailSubject     = "Subject";
	public string MailBody        = "Body";
	
	private System.Net.Mail.SmtpClient _stampClient = null;
	
	void Update () {
		
		if (Input.GetKeyUp ("s")) {
			_send ();
		}
		
		if (Input.GetKeyUp ("c")) {
			_cancelSend ();
		}
		
	}
	
	void _send () {
		
		System.Net.Mail.MailMessage msg = new System.Net.Mail.MailMessage (
			MailFromAddress,
			MailToAddress,
			MailSubject,
			MailBody
			);
		
		if (_stampClient == null) {
			_stampClient = new System.Net.Mail.SmtpClient (MailHost);
			_stampClient.SendCompleted += new System.Net.Mail.SendCompletedEventHandler (_sendCompleteHandler);
		}
		
		_stampClient.Port                  = MailPort;
		_stampClient.EnableSsl             = true;
		_stampClient.DeliveryMethod        = System.Net.Mail.SmtpDeliveryMethod.Network;
		_stampClient.UseDefaultCredentials = false;
		_stampClient.Credentials           = new System.Net.NetworkCredential (MailFromAddress, MailPassword) as System.Net.ICredentialsByHost;
		System.Net.ServicePointManager.ServerCertificateValidationCallback = 
			delegate
			(
				object s,
				System.Security.Cryptography.X509Certificates.X509Certificate certificate,
				System.Security.Cryptography.X509Certificates.X509Chain       chain,
				System.Net.Security.SslPolicyErrors                           sslPolicyErrors
			) 
		{
			return true; 
		};

		_stampClient.SendAsync (msg, msg);
	
	}
	
	void _cancelSend () {
		
		if (_stampClient != null) {
			_stampClient.SendAsyncCancel ();
		}
		
	}
	
	void _sendCompleteHandler (object sender, System.ComponentModel.AsyncCompletedEventArgs e) {
		
		System.Net.Mail.MailMessage msg = (System.Net.Mail.MailMessage) e.UserState;
		
		if (e.Cancelled) {
			Debug.Log ("<color=yellow>Cancelled sending message.</color>");
		} else if (e.Error != null) {
			Debug.Log ("<color=red>An error has occurred.</color>");
			Debug.Log (e.Error.ToString ());
		} else {
			Debug.Log ("<color=lime>Mail has been sent.</color>");
		}
		
		msg.Dispose ();
	}
}