如何在 ASP.NET C# 中发送电子邮件答案

【问题标题】：How to send email in ASP.NET C#如何在 ASP.NET C# 中发送电子邮件
【发布时间】：2013-08-22 00:19:32
【问题描述】：

我对@987654321@ C# 领域非常陌生。我打算通过 ASP.NET C# 发送邮件，这是来自我的ISP 的SMTP 地址：

smtp-proxy.tm.net.my

以下是我尝试做的，但失败了。

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="SendMail" %>
<html>
<head id="Head1" runat="server"><title>Email Test Page</title></head>
<body>
    <form id="form1" runat="server">
        Message to: <asp:TextBox ID="txtTo" runat="server" /><br>
        Message from: <asp:TextBox ID="txtFrom" runat="server" /><br>
        Subject: <asp:TextBox ID="txtSubject" runat="server" /><br>
        Message Body:<br>
        <asp:TextBox ID="txtBody" runat="server" Height="171px" TextMode="MultiLine"  Width="270px" /><br>
        <asp:Button ID="Btn_SendMail" runat="server" onclick="Btn_SendMail_Click" Text="Send Email" /><br>
        <asp:Label ID="Label1" runat="server" Text="Label"></asp:Label>
    </form>
</body>
</html>

下面是我的code-behind：

using System;
using System.Web.UI.WebControls;
using System.Net.Mail;
public partial class SendMail : System.Web.UI.Page
{
    protected void Btn_SendMail_Click(object sender, EventArgs e)
    {
        MailMessage mailObj = new MailMessage(
            txtFrom.Text, txtTo.Text, txtSubject.Text, txtBody.Text);
        SmtpClient SMTPServer = new SmtpClient("127.0.0.1");
        try
        {
            SMTPServer.Send(mailObj);
        }
        catch (Exception ex)
        {
            Label1.Text = ex.ToString();
        }
    }
}

PS：很抱歉，我无法理解接收方/发送方 SMTP 概念，因此我试图从这里理解整个概念。

【问题讨论】：

当你点击按钮时，它会到达后面的代码吗？
您是否在 localhost 的 IIS 中设置了 smtp？失败是什么？您有 ISP 的邮件帐户吗？

标签： c# asp.net email smtp

【解决方案1】：

只需通过下面的代码。

SmtpClient smtpClient = new SmtpClient("mail.MyWebsiteDomainName.com", 25);

smtpClient.Credentials = new System.Net.NetworkCredential("info@MyWebsiteDomainName.com", "myIDPassword");
// smtpClient.UseDefaultCredentials = true; // uncomment if you don't want to use the network credentials
smtpClient.DeliveryMethod = SmtpDeliveryMethod.Network;
smtpClient.EnableSsl = true;
MailMessage mail = new MailMessage();

//Setting From , To and CC
mail.From = new MailAddress("info@MyWebsiteDomainName", "MyWeb Site");
mail.To.Add(new MailAddress("info@MyWebsiteDomainName"));
mail.CC.Add(new MailAddress("MyEmailID@gmail.com"));

smtpClient.Send(mail);

【讨论】：

Thamotharan's 是正确的。发送纯文本或 HTML 正文。对于快速而肮脏的普通电子邮件。这是在邮件正文中嵌入 HTML 标记的一个很好的示例。 Inline HTML code。 StringBuilder 对于创建更大的消息非常有用。还有
我发现这很有帮助。根据文档，虽然将 UseDefaultCredentials 设置为 true 意味着将不会发送给定的凭据。这是要弄清楚的棘手部分。
请注意，MailMessage 和 SmtpClient 都实现了 IDisposable 并且应该在 using 语句中使用（或以其他方式处理）
可能需要配置一个gmail账号，如下。 “不太安全的应用程序”的值应设置为“启用”。在客户端使用域“smtp.gmail.com”和端口 587。

【解决方案2】：

尝试改用此代码。注意：在“发件人地址”中提供正确的电子邮件 ID 和密码。

protected void btn_send_Click(object sender, EventArgs e)
{

    System.Net.Mail.MailMessage mail = new System.Net.Mail.MailMessage();
    mail.To.Add("to gmail address");
    mail.From = new MailAddress("from gmail address", "Email head", System.Text.Encoding.UTF8);
    mail.Subject = "This mail is send from asp.net application";
    mail.SubjectEncoding = System.Text.Encoding.UTF8;
    mail.Body = "This is Email Body Text";
    mail.BodyEncoding = System.Text.Encoding.UTF8;
    mail.IsBodyHtml = true;
    mail.Priority = MailPriority.High;
    SmtpClient client = new SmtpClient();
    client.Credentials = new System.Net.NetworkCredential("from gmail address", "your gmail account password");
    client.Port = 587;
    client.Host = "smtp.gmail.com";
    client.EnableSsl = true;
    try
    {
        client.Send(mail);
        Page.RegisterStartupScript("UserMsg", "<script>alert('Successfully Send...');if(alert){ window.location='SendMail.aspx';}</script>");
    }
    catch (Exception ex)
    {
        Exception ex2 = ex;
        string errorMessage = string.Empty;
        while (ex2 != null)
        {
            errorMessage += ex2.ToString();
            ex2 = ex2.InnerException;
        }
        Page.RegisterStartupScript("UserMsg", "<script>alert('Sending Failed...');if(alert){ window.location='SendMail.aspx';}</script>");
    }
}

【讨论】：

所以我在我的 ASP.net 页面中设置了一个带有下拉列表/文本框的表单。它会以同样的方式工作吗？谢谢。
这段代码在本地服务器机器人上运行，而不是来自托管老爹服务器。为什么？

【解决方案3】：

你可以像这样使用 hotmail 试试这个：-

MailMessage o = new MailMessage("From", "To","Subject", "Body");
NetworkCredential netCred= new NetworkCredential("Sender Email","Sender Password");
SmtpClient smtpobj= new SmtpClient("smtp.live.com", 587); 
smtpobj.EnableSsl = true;
smtpobj.Credentials = netCred;
smtpobj.Send(o);

【讨论】：

【解决方案4】：

尝试以下方法：

try
{
    var fromEmailAddress =  ConfigurationManager.AppSettings["FromEmailAddress"].ToString();
    var fromEmailDisplayName = ConfigurationManager.AppSettings["FromEmailDisplayName"].ToString();
    var fromEmailPassword = ConfigurationManager.AppSettings["FromEmailPassword"].ToString();
    var smtpHost = ConfigurationManager.AppSettings["SMTPHost"].ToString();
    var smtpPort = ConfigurationManager.AppSettings["SMTPPort"].ToString();

    string body = "Your registration has been done successfully. Thank you.";
    MailMessage message = new MailMessage(new MailAddress(fromEmailAddress, fromEmailDisplayName), new MailAddress(ud.LoginId, ud.FullName));
    message.Subject = "Thank You For Your Registration";
    message.IsBodyHtml = true;
    message.Body = body;

    var client = new SmtpClient();
    client.Credentials = new NetworkCredential(fromEmailAddress, fromEmailPassword);
    client.Host = smtpHost;
    client.EnableSsl = true;
    client.Port = !string.IsNullOrEmpty(smtpPort) ? Convert.ToInt32(smtpPort) : 0;
    client.Send(message);
}
catch (Exception ex)
{
    throw (new Exception("Mail send failed to loginId " + ud.LoginId + ", though registration done."));
}

然后在你的 web.config 中添加以下内容

<!--Email Config-->
<add key="FromEmailAddress" value="sender emailaddress"/>
<add key="FromEmailDisplayName" value="Display Name"/>
<add key="FromEmailPassword" value="sender Password"/>
<add key="SMTPHost" value="smtp-proxy.tm.net.my"/>
<add key="SMTPPort" value="smptp Port"/>

【讨论】：

【解决方案5】：

你可以试试 MailKit MailKit 是一个开源跨平台 .NET 邮件客户端库，它基于 MimeKit 并针对移动设备进行了优化。您可以在您的应用程序中轻松使用。您可以从here下载。

                MimeMessage mailMessage = new MimeMessage();
                mailMessage.From.Add(new MailboxAddress(fromName, from@address.com));
                mailMessage.Sender = new MailboxAddress(senderName, sender@address.com);
                mailMessage.To.Add(new MailboxAddress(emailid, emailid));
                mailMessage.Subject = subject;
                mailMessage.ReplyTo.Add(new MailboxAddress(replyToAddress));
                mailMessage.Subject = subject;
                var builder = new BodyBuilder();
                builder.TextBody = "Hello There";           
                try
                {
                    using (var smtpClient = new SmtpClient())
                    {
                        smtpClient.Connect("HostName", "Port", MailKit.Security.SecureSocketOptions.None);
                        smtpClient.Authenticate("user@name.com", "password");

                        smtpClient.Send(mailMessage);
                        Console.WriteLine("Success");
                    }
                }
                catch (SmtpCommandException ex)
                {
                    Console.WriteLine(ex.ToString());              
                }
                catch (Exception ex)
                {
                    Console.WriteLine(ex.ToString());                
                }

【讨论】：

【解决方案6】：

检查一下....它有效

http://www.aspnettutorials.com/tutorials/email/email-aspnet2-csharp/

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Net.Mail;

public partial class _Default : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {

    }

    protected void btnSubmit_Click(object sender, EventArgs e)
    {
        try
        {
            MailMessage message = new MailMessage(txtFrom.Text, txtTo.Text, txtSubject.Text, txtBody.Text);
            SmtpClient emailClient = new SmtpClient(txtSMTPServer.Text);
            emailClient.Send(message);
            litStatus.Text = "Message Sent";
        }
        catch (Exception ex)
        {
            litStatus.Text=ex.ToString();
        }
    }
}

【讨论】：

以上链接无效，您可以在此处查看以asp net web-form发送电子邮件的分步指南：qawithexperts.com/article/asp-net/…

【解决方案7】：

只传参数喜欢 body - 来自客户的内容（查询）
主题 - 邮件主题中定义的主题
用户名 - 没有任何名称
邮件 - 邮件（必填）

   public static bool SendMail(String body, String subject, string username, String mail)
    {
        bool isSendSuccess = false;
        try
        {
            var fromEmailAddress = ConfigurationManager.AppSettings["FromEmailAddress"].ToString();
            var fromEmailDisplayName = ConfigurationManager.AppSettings["FromEmailDisplayName"].ToString();
            var fromEmailPassword = ConfigurationManager.AppSettings["FromEmailPassword"].ToString();
            var smtpHost = ConfigurationManager.AppSettings["SMTPHost"].ToString();
            var smtpPort = ConfigurationManager.AppSettings["SMTPPort"].ToString();


            MailMessage message = new MailMessage(new MailAddress(fromEmailAddress, fromEmailDisplayName),
                new MailAddress(mail, username));
            message.Subject = subject;
            message.IsBodyHtml = true;
            message.Body = body;

            var client = new SmtpClient();
            client.UseDefaultCredentials = false;
            client.Credentials = new NetworkCredential(fromEmailAddress, fromEmailPassword);
            client.Host = smtpHost;
            client.EnableSsl = false;
            client.Port = !string.IsNullOrEmpty(smtpPort) ? Convert.ToInt32(smtpPort) : 0;
            client.Send(message);
            isSendSuccess = true;
        }
        catch (Exception ex)
        {
            throw (new Exception("Mail send failed to loginId " + mail + ", though registration done."+ex.ToString()+"\n"+ex.StackTrace));
        }

        return isSendSuccess;
    }

如果您使用 go daddy 服务器这项工作。在 web.config 中添加这个

  <appSettings>
    ---other ---setting

    <add key="FromEmailAddress" value="myemail@gmail.com" />
    <add key="FromEmailDisplayName" value="anyname" />
    <add key="FromEmailPassword" value="mypassword@" />
    <add key="SMTPHost" value="relay-hosting.secureserver.net" />
    <add key="SMTPPort" value="25" />

</appSettings>

如果您使用的是 localhost 或 vps 服务器，请将此配置更改为此

 <appSettings>
    ---other ---setting

    <add key="FromEmailAddress" value="myemail@gmail.com" />
    <add key="FromEmailDisplayName" value="anyname" />
    <add key="FromEmailPassword" value="mypassword@" />
    <add key="SMTPHost" value="smtp.gmail.com" /> 
    <add key="SMTPPort" value="587" />
</appSettings>

修改代码

          client.EnableSsl = true;

如果您使用的是 gmail，请启用安全应用。使用此链接 https://myaccount.google.com/lesssecureapps?pli=1&rapt=AEjHL4Pd6h3XxE663Flvd-FfeRXxW_eNrIsGTBlZklgkAHZEeuHvheCQuZ1-djB9uIWaB-2EV7hyLCU0dWKA7D0JzYKe4ZRkuA

【讨论】：

【解决方案8】：

    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Globalization;
    using System.Text.RegularExpressions;
    
    /// <summary>
    /// Summary description for RegexUtilities
    /// </summary>
    public class RegexUtilities
    {
        bool InValid = false;
    
        public bool IsValidEmail(string strIn)
        {
            InValid = false;
            if (String.IsNullOrEmpty(strIn))
                return false;
    
            // Use IdnMapping class to convert Unicode domain names.
            strIn = Regex.Replace(strIn, @"(@)(.+)$", this.DomainMapper);
            if (InValid)
                return false;
    
            // Return true if strIn is in valid e-mail format. 
            return Regex.IsMatch(strIn, @"^(?("")(""[^""]+?""@)|(([0-9a-z]((\.(?!\.))|[-!#\$%&'\*\+/=\?\^`\{\}\|~\w])*)(?<=[0-9a-z])@))" + @"(?(\[)(\[(\d{1,3}\.){3}\d{1,3}\])|(([0-9a-z][-\w]*[0-9a-z]*\.)+[a-z0-9]{2,17}))$",
                   RegexOptions.IgnoreCase);
        }
    
        private string DomainMapper(Match match)
        {
            // IdnMapping class with default property values.
            IdnMapping idn = new IdnMapping();
    
            string domainName = match.Groups[2].Value;
            try
            {
                domainName = idn.GetAscii(domainName);
            }
            catch (ArgumentException)
            {
                InValid = true;
            }
            return match.Groups[1].Value + domainName;
        }
    
    }



 private void GetSendEmInfo()
    {
        #region For Get All Type Email Informations..!!
        IPL.DoId = ddlName.SelectedValue;
        DataTable dt = IdBL.GetEmailS(IPL);
        if (dt.Rows.Count > 0)
        {
            hid_MailId.Value = dt.Rows[0]["MailId"].ToString();
            hid_UsedPName.Value = dt.Rows[0]["UName"].ToString();
            hid_EmailSubject.Value = dt.Rows[0]["EmailSubject"].ToString();
            hid_EmailBody.Value = dt.Rows[0]["EmailBody"].ToString();
            hid_EmailIdName.Value = dt.Rows[0]["EmailIdName"].ToString();
            hid_EmPass.Value = dt.Rows[0]["EPass"].ToString();
            hid_SeName.Value = dt.Rows[0]["SenName"].ToString();
            hid_TNo.Value = dt.Rows[0]["TeNo"].ToString();
            hid_EmaLimit.Value = dt.Rows[0]["EmailLimit"].ToString();
            hidlink.Value = dt.Rows[0][link"].ToString();
        }
        #endregion

        #region For Set Some Local Variables..!!
        int StartLmt, FinalLmt, SendCurrentMail;
        StartLmt = FinalLmt = SendCurrentMail = 0;
        bool Valid_LimitMail;
        Valid_LimitMail = true;
        /**For Get Finalize Limit For Send Mail**/
        FinalLmt = Convert.ToInt32(hid_EmailmaxLimit.Value);
        #region For Check Email Valid Limits..!!
        if (FinalLmt > 0)
        {
            Valid_LimitMail = true;
        }
        else
        {
            Valid_LimitMail = false;
        }
        #endregion
        /**For Get Finalize Limit For Send Mail**/
        #endregion

        if (Valid_LimitMail == true)
        {
            #region For Send Current Email Status..!!
            bool EmaiValid;
            string CreateFileName;
            string retmailflg = null;
            EmaiValid = false;
            #endregion

            #region For Set Start Limit And FinalLimit Send No Of Email..!!
            mPL.SendDate = DateTime.Now.ToString("dd-MMM-yyyy");
            DataTable dtsendEmail = m1BL.GetEmailSendLog(mPL);
            if (dtsendEmail.Rows.Count > 0)
            {
                StartLmt = Convert.ToInt32(dtsendEmail.Rows[0]["SendNo_Of_Email"].ToString());
            }
            else
            {
                StartLmt = 0;
            }
            #endregion

            #region For Find Grid View Controls..!!
            for (int i = 0; i < GrdEm.Rows.Count; i++)
            {
                #region For Find Grid view Controls..!!
                CheckBox Chk_SelectOne = (CheckBox)GrdEmp.Rows[i].FindControl("chkSingle");
                Label lbl_No = (Label)GrdEmAtt.Rows[i].FindControl("lblGrdCode");
                lblCode.Value = lbl_InNo.Text;

                Label lbl_EmailId = (Label)GrdEomAtt.Rows[i].FindControl("lblGrdEmpEmail");

                #endregion

                /**Region For If Check Box Checked Then**/
                if (Chk_SelectOne.Checked == true)
                {
                    if (!string.IsNullOrEmpty(lbl_EmailId.Text))
                    {
                        #region For When Check Box Checked..!!
                        /**If Start Limit Less Or Equal To Then Condition Performs**/
                        if (StartLmt < FinalLmt)
                        {
                            StartLmt = StartLmt + 1;
                        }
                        else
                        {
                            Valid_LimitMail = false;
                            EmaiValid = false;
                        }
                        /**End Region**/
                        string[] SplitClients_Email = lbl_EmailId.Text.Split(',');
                        string Send_Email, Hold_Email;
                        Send_Email = Hold_Email = "";

                        int CountEmail;/**Region For Count Total Email**/
                        CountEmail = 0;/**First Time Email Counts Zero**/

                        Hold_Email = SplitClients_Email[0].ToString().Trim().TrimEnd().TrimStart().ToString();
                        /**Region For If Clients Have One Email**/
                        #region For First Emails Send On Client..!!
                        if (SplitClients_Email[0].ToString() != "")
                        {
                            if (EmailRegex.IsValidEmail(Hold_Email))
                            {
                                Send_Email = Hold_Email;
                                CountEmail = 1;
                                EmaiValid = true;
                            }
                            else
                            {
                                EmaiValid = false;
                            }
                        }
                        #endregion
                        /**Region For If Clients Have One Email**/
                        /**Region For If Clients Have Two Email**/

                        /**Region For If Clients Have Two Email**/
                        if (EmaiValid == true)
                        {
                            #region For Create Email Body And Create File Name..!!
                            //fofile = Server.MapPath("PDFs");
                            fofile = Server.MapPath("~/vvv/vvvv/") + "/";
                            CreateFileName = lbl_INo.Text.ToString() + "_1" + ".Pdf";/**Create File Name**/
                            string[] orimail = Send_Email.Split(',');
                            string Billbody, TempInvoiceId;
                            // DateTime dtLstdate = new DateTime(Convert.ToInt32(txtYear.Text), Convert.ToInt32(ddlMonth.SelectedValue), 16);

                            //  DateTime IndtLmt = dtLstdate.AddMonths(1);
                            TempInvoiceId = "";

                            //byte[] Buffer = Encrypt.Encryptiondata(lbl_InvoiceNo.Text.ToString());
                            //TempInvoiceId = Convert.ToBase64String(Buffer);


                            #region Create Encrypted Path


                            byte[] EncCode = Encrypt.Encryptiondata(lbl_INo.Text);
                            hidEncrypteCode.Value = Convert.ToBase64String(EncECode);
                            #endregion

                        

                            //#region Create Email Body !!
                            //body = hid_EmailBody.Value.Replace("@greeting", lbl_CoName.Text).Replace("@free", hid_ToNo.Value).Replace("@llnk", "<a style='font-family: Tahoma; font-size: 10pt; color: #800000; font-weight: bold' href='http://1ccccc/ccc/ccc/ccc.aspx?EC=" + hidEncryptedCode.Value+ "' > C cccccccc </a>");
                          

                            body = hid_EmailBody.Value.Replace("@greeting", "Hii").Replace("@No", hid_No.Value);/*For Mail*/
                            //#endregion



                            #region For Email Sender Informations..!!
                            for (int j = 0; j < CountEmail; j++)
                            {
                                //if (File.Exists(fofile + "\\" + CreateFileName))
                                //{
                                #region
                                lbl_EmailId.Text = orimail[j];
                                retmailflg = "";

                                /**Region For Send Email For Clients**/
                                //retmailflg = SendPreMail("Wp From " + lbl_CName.Text + "", body, lbl_EmailId.Text, lbl_IeNo.Text, hid_EmailIdName.Value, hid_EmailPassword.Value);
                                retmailflg = SendPreMail(hid_EmailSubject.Value, Body, lbl_EmailId.Text, lbl_No.Text, hid_EmailIdName.Value, hid_EmailPassword.Value);
                                /**End Region**/

                                /**Region For Create Send Email Log  When Email Send Successfully**/
                                if (retmailflg == "True")
                                {
                                    SendCurrentMail = Convert.ToInt32(SendCurrentMail) + 1;
                                    StartLmt = Convert.ToInt32(StartLmt) + 1;

                                    if (SendCurrentMail > 0)
                                    {
                                        CreateEmailLog(lbl_InNo.Text, StartLmt, hid_EmailIdName.Value, lbl_EmailId.Text);
                                        
                                    }
                                }
                                

                                /**End Region**/
                                #endregion
                                //}
                            }
                            #endregion
                        }
                        #endregion
                    }
                }
                /**End Region**/
            }
            #endregion

        }
       
    }
    private void CreateEmailLog(string UniqueId, int StartLmt, string FromEmailId, string TotxtEmailId)
    {
        FPL.EmailId_From = FromEmailId;
        FPL.To_EmailId = TotxtEmailId;
        FPL.SendDate = DateTime.Now.ToString("dd-MMM-yyyy");
        FPL.EmailUniqueId = UniqueId;
        FPL.SendNo_Of_Email = StartLmt.ToString();
        FPL.LoginUserId = Session["LoginUserId"].ToString();
        int i = FBL.InsertEmaDoc(FPL);
    }

    public string SendPreMail(string emsub, string embody, string EmailId, string FileId, string EmailFromId, string Password)
    {
        string retval = "False";
        try
        {
            string emailBody, emailSubject, emailToList, emailFrom,
            accountPassword, smtpServer;
            bool enableSSL;
            int port;

            emailBody = embody;
            emailSubject = emsub;
            emailToList = EmailId;
            emailFrom = EmailFromId;
            accountPassword = Password;
            smtpServer = "smtp.gmail.com";
            enableSSL = true;
            port = 587;

            string crefilename;
            string fofile;
            fofile = Server.MapPath("PDF");
            crefilename = FileId + ".Pdf";

            string[] att = { crefilename };

            string retemail, insertqry;
            retemail = "";

            retemail = SendEmail(emailBody, emailSubject, emailFrom, emailToList, att, smtpServer, enableSSL, accountPassword, port);

            if (retemail == "True")
            {

                retval = retemail;
            }
        }
        catch
        {
            retval = "False";
        }
        finally
        {

        }
        return retval;
    }

    public string SendEmail(string emailBody, string emailSubject, string emailFrom, string emailToList, string[] attachedFiles, string smtpIPAddress, bool enableSSL, string accountPassword, int port)
    {
        MailMessage mail = new MailMessage();
        string retflg;
        retflg = "False";
        try
        {
            mail.From = new MailAddress(emailFrom);
            if (emailToList.Contains(";"))
            {
                emailToList = emailToList.Replace(";", ",");
            }
            mail.To.Add(emailToList);

            mail.Subject = emailSubject;
            mail.IsBodyHtml = true;
            mail.Body = emailBody;


            SmtpClient smtp = new SmtpClient();
            smtp.Host = "smtp.gmail.com";
            smtp.EnableSsl = true;
            NetworkCredential NetworkCred = new NetworkCredential(emailFrom, accountPassword);
            smtp.UseDefaultCredentials = true;
            smtp.Credentials = NetworkCred;
            smtp.Port = 587;
            smtp.Send(mail);
            retflg = "True";

        }
        catch
        {
            retflg = "False";
        }
        finally
        {
            mail.Dispose();
        }
        return retflg;
    }

【讨论】：

【解决方案9】：

如果您想在 razor 中生成电子邮件正文，可以使用Mailzory。另外，你可以从here下载nuget包。

// template path
var viewPath = Path.Combine("Views/Emails", "hello.cshtml");
// read the content of template and pass it to the Email constructor
var template = File.ReadAllText(viewPath);

var email = new Email(template);

// set ViewBag properties
email.ViewBag.Name = "Johnny";
email.ViewBag.Content = "Mailzory Is Funny";

// send email
var task = email.SendAsync("mailzory@outlook.com", "subject");
task.Wait()

【讨论】：

【解决方案10】：

据此：

SmtpClient 及其网络类型设计不佳，我们强烈建议您使用https://github.com/jstedfast/MailKit 和 https://github.com/jstedfast/MimeKit 代替。

参考：https://docs.microsoft.com/en-us/dotnet/api/system.net.mail.smtpclient?view=netframework-4.8

最好用MailKit发邮件：

var message = new MimeMessage ();
            message.From.Add (new MailboxAddress ("Joey Tribbiani", "joey@friends.com"));
            message.To.Add (new MailboxAddress ("Mrs. Chanandler Bong", "chandler@friends.com"));
            message.Subject = "How you doin'?";

            message.Body = new TextPart ("plain") {
                Text = @"Hey Chandler,
I just wanted to let you know that Monica and I were going to go play some paintball, you in?
-- Joey"
            };

            using (var client = new SmtpClient ()) {
                // For demo-purposes, accept all SSL certificates (in case the server supports STARTTLS)
                client.ServerCertificateValidationCallback = (s,c,h,e) => true;

                client.Connect ("smtp.friends.com", 587, false);

                // Note: only needed if the SMTP server requires authentication
                client.Authenticate ("joey", "password");

                client.Send (message);
                client.Disconnect (true);
            }

【讨论】：

【解决方案11】：

Google 可能会阻止来自不使用现代安全标准的某些应用或设备的登录尝试。由于这些应用和设备更容易被入侵，因此阻止它们有助于确保您的帐户更安全。

一些不支持最新安全标准的应用示例包括：

安装 iOS 6 或更低版本的 iPhone 或 iPad 上的邮件应用
Windows 手机上 8.1 版本之前的邮件应用
某些桌面邮件客户端，例如 Microsoft Outlook 和 Mozilla Thunderbird

因此，您必须在您的 Google 帐户中启用不太安全的登录（或不太安全的应用访问权限）。

登录谷歌账号后，前往：

https://www.google.com/settings/security/lesssecureapps 要么 https://myaccount.google.com/lesssecureapps

在 C# 中，您可以使用以下代码：

        MimeMessage message = new MimeMessage();
        BodyBuilder Attachmint = new BodyBuilder();
        message.From.Add(new MailboxAddress("name sender", "Mail From"));
        message.To.Add(MailboxAddress.Parse("Mail To"));
        message.Subject = Subject;
        message.Body = new TextPart("plain")
        {
            Text = tex_body.Text + Massage
        };

        Attachmint.Attachments.Add("Attatchment Path");
        message.Body = Attachmint.ToMessageBody();

        SmtpClient client = new SmtpClient();
        client.Connect("smtp.gmail.com", 465, true);
        client.Authenticate("Mail from", "Password mail");
        client.Send(message);

您可以将邮件从 Gmail 发送到作为 X@PrivetCompany.com 的私人邮箱

【讨论】：

【解决方案12】：

MailMessage mm = new MailMessage(txtEmail.Text, txtTo.Text);
mm.Subject = txtSubject.Text;
mm.Body = txtBody.Text;
if (fuAttachment.HasFile)//file upload select or not
{
    string FileName = Path.GetFileName(fuAttachment.PostedFile.FileName);
    mm.Attachments.Add(new Attachment(fuAttachment.PostedFile.InputStream, FileName));
}
mm.IsBodyHtml = false;
SmtpClient smtp = new SmtpClient();
smtp.Host = "smtp.gmail.com";
smtp.EnableSsl = true;
NetworkCredential NetworkCred = new NetworkCredential(txtEmail.Text, txtPassword.Text);
smtp.UseDefaultCredentials = true;
smtp.Credentials = NetworkCred;
smtp.Port = 587;
smtp.Send(mm);
Response.write("Send Mail");

观看视频：https://www.youtube.com/watch?v=bUUNv-19QAI

【讨论】：

【解决方案13】：

这是最容易测试的脚本。

<%@ Import Namespace="System.Net" %> 
<%@ Import Namespace="System.Net.Mail" %> 

<script language="C#" runat="server"> 
    protected void Page_Load(object sender, EventArgs e) 
    { 
       //create the mail message 
        MailMessage mail = new MailMessage(); 

        //set the addresses 
        mail.From = new MailAddress("From email account"); 
        mail.To.Add("To email account"); 

        //set the content 
        mail.Subject = "This is a test email from C# script"; 
        mail.Body = "This is a test email from C# script"; 
        //send the message 
         SmtpClient smtp = new SmtpClient("mail.domainname.com"); 

         NetworkCredential Credentials = new NetworkCredential("to email account", "Password"); 
         smtp.Credentials = Credentials;
         smtp.Send(mail); 
         lblMessage.Text = "Mail Sent"; 
    } 
</script> 
<html> 
<body> 
    <form runat="server"> 
        <asp:Label id="lblMessage" runat="server"></asp:Label> 
    </form> 
</body>

【讨论】：

为什么会选择把它放在视图中而不让控制器处理呢？
刚刚问了关于通过 ASP.NET C# 发送电子邮件的问题。没有提到在脚本中设置控制器。