C# 为什么我会得到'；无法分配属性"；发送SMTP电子邮件时？

我不明白为什么这个代码不起作用。我收到一个错误，说明无法分配属性

MailMessage mail = new MailMessage();
SmtpClient client = new SmtpClient();            
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.gmail.com";
mail.To = "user@hotmail.com"; // <-- this one
mail.From = "you@yourcompany.com";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);

MailMessage mail=newmailmessage（）；
SmtpClient=新的SmtpClient（）；
客户端端口=25；
client.DeliveryMethod=SmtpDeliveryMethod.Network；
client.UseDefaultCredentials=false；
client.Host=“smtp.gmail.com”；
mail.To=”user@hotmail.com"; //  这：

mail.To = "user@hotmail.com";

应该是：

mail.To.Add(new MailAddress("user@hotmail.com"));

mail.To
和
mail.From
是只读的。将它们移动到构造函数

using System.Net.Mail;

...

MailMessage mail = new MailMessage("you@yourcompany.com", "user@hotmail.com");
SmtpClient client = new SmtpClient();
client.Port = 25;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Host = "smtp.gmail.com";
mail.Subject = "this is a test email.";
mail.Body = "this is my test email body";
client.Send(mail);

终于开始工作了：）

很抱歉之前拼写不好
我就是这样写的。希望你觉得有用

public static void SendMail(MailMessage Message)
{
    SmtpClient client = new SmtpClient();
    client.Host = "smtp.googlemail.com";
    client.Port = 587;
    client.UseDefaultCredentials = false;
    client.DeliveryMethod = SmtpDeliveryMethod.Network;
    client.EnableSsl = true;
    client.Credentials = new NetworkCredential("myemail@gmail.com", "password");
    client.Send(Message); 
}

MailMessage objeto_mail = new MailMessage();
SmtpClient client = new SmtpClient();
client.Port = 25;
client.Host = "smtp.internal.mycompany.com";
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("user", "Password");
objeto_mail.From = new MailAddress("from@server.com");
objeto_mail.To.Add(new MailAddress("to@server.com"));
objeto_mail.Subject = "Password Recover";
objeto_mail.Body = "Message";
client.Send(objeto_mail);

如果您希望您的电子邮件和密码不显示在代码中，并且希望您的公司电子邮件客户端服务器使用下面使用的windows凭据，请查看更多详细信息

client.Credentials = CredentialCache.DefaultNetworkCredentials;

使用发件人和收件人的电子邮件地址初始化
邮件。应该是这样的

string from = "codeforwin@gmail.com";  //Senders email   
string to = "reciever@gmail.com";  //Receiver's email  
MailMessage msg = new MailMessage(from, to); 

阅读
的完整代码片段，这样也可以

string your_id = "your_id@gmail.com";
string your_password = "password";
try
{
   SmtpClient client = new SmtpClient
   {
     Host = "smtp.gmail.com",
     Port = 587,
     EnableSsl = true,
     DeliveryMethod = SmtpDeliveryMethod.Network,
     Credentials = new System.Net.NetworkCredential(your_id, your_password),
     Timeout = 10000,
   };
   MailMessage mm = new MailMessage(your_iD, "recepient@gmail.com", "subject", "body");
   client.Send(mm);
   Console.WriteLine("Email Sent");
 }
 catch (Exception e)
 {
   Console.WriteLine("Could not end email\n\n"+e.ToString());
 }

查看视频：
//希望你觉得它有用，它包含的东西太多了
字符串smtpAddress=“smtp.xyz.com”；
int端口号=587；
bool enablesl=true；
字符串m_userName=”support@xyz.com";
字符串m_UserpassWord=“56436578”；
公共无效发送电子邮件（客户_客户）
{
字符串emailID=gghdgfh@gmail.com;
字符串userName=DemoUser；
字符串emailFrom=”qwerty@gmail.com";
字符串密码=“qwerty”；
字符串emailTo=emailID；
//你们可以把邮件的主题放在这里
string subject=“注册”；
//正文
字符串体=”；
正文+=“Aspen报告工具”；
正文+=“
”；
正文+=“亲爱的”+用户名+“，”；
正文+=“
”；
身体+=“”；
body+=“感谢您的注册
”；
正文+=“完成注册过程”
”；
正文+=“
”；
body+=“谢谢”；
正文+=“
”；
身体+=“团队”；
正文+=”；
//这是使用System.Net.Mail和System.Net完成的；
使用（MailMessage mail=newmailmessage（））
{
mail.From=新邮件地址（emailFrom）；
mail.To.Add（emailTo）；
mail.Subject=主题；
mail.Body=Body；
mail.IsBodyHtml=true；
//如果发送纯文本，则可以设置为false。
使用（SmtpClient smtp=新SmtpClient（smtpAddress，端口号））
{
smtp.Credentials=新的网络凭据（emailFrom，密码）；
smtp.EnableSsl=启用SSL；
smtp.发送（邮件）；
}
}
}
只需尝试一下：

string smtpAddress = "smtp.gmail.com";
int portNumber = 587;
bool enableSSL = true;
string emailFrom = "companyemail";
string password = "password";
string emailTo = "Your email";
string subject = "Hello!";
string body = "Hello, Mr.";
MailMessage mail = new MailMessage();
mail.From = new MailAddress(emailFrom);
mail.To.Add(emailTo);
mail.Subject = subject;
mail.Body = body;
mail.IsBodyHtml = true;
using (SmtpClient smtp = new SmtpClient(smtpAddress, portNumber))
{
   smtp.Credentials = new NetworkCredential(emailFrom, password);
   smtp.EnableSsl = enableSSL;
   smtp.Send(mail);
}

首先转到并使“允许较不安全的应用程序”true

然后使用下面的代码。只有当您的发件人电子邮件地址来自gmail时，以下代码才有效

static void SendEmail()
    {
        string mailBodyhtml =
            "<p>some text here</p>";
        var msg = new MailMessage("from@gmail.com", "to1@gmail.com", "Hello", mailBodyhtml);
        msg.To.Add("to2@gmail.com");
        msg.IsBodyHtml = true;
        var smtpClient = new SmtpClient("smtp.gmail.com", 587); //**if your from email address is "from@hotmail.com" then host should be "smtp.hotmail.com"**
        smtpClient.UseDefaultCredentials = true;
        smtpClient.Credentials = new NetworkCredential("from@gmail.com", "password");
        smtpClient.EnableSsl = true;
        smtpClient.Send(msg);
        Console.WriteLine("Email Sent Successfully");
    }

static void sendmail（）
{
字符串mailBodyhtml=
“这里有一些文字
”；
var msg=新邮件消息（“from@gmail.com", "to1@gmail.com“，”你好“，mailBodyhtml）；
msg.To.Add（“to2@gmail.com");
msg.IsBodyHtml=true；
var smtpClient=new smtpClient（“smtp.gmail.com”，587）；//**如果您的发件人电子邮件地址为“from@hotmail.com那么主机应该是“smtp.hotmail.com”**
smtpClient.UseDefaultCredentials=true；
smtpClient.Credentials=新的网络凭据（“from@gmail.com“，”密码“）；
smtpClient.EnableSsl=true；
smtpClient.Send（msg）；
Console.WriteLine（“成功发送电子邮件”）；
}
从2017年3月起，这对我来说就起作用了。
从上面的解决方案开始，“终于开始工作了：）”一开始不起作用

SmtpClient client = new SmtpClient();
client.Port =  587;
client.Host = "smtp.gmail.com";
client.EnableSsl = true;
client.Timeout = 10000;
client.DeliveryMethod = SmtpDeliveryMethod.Network;
client.UseDefaultCredentials = false;
client.Credentials = new System.Net.NetworkCredential("<me>@gmail.com", "<my pw>");
MailMessage mm = new MailMessage(from_addr_text, to_addr_text, msg_subject, msg_body);
mm.BodyEncoding = UTF8Encoding.UTF8;
mm.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;

client.Send(mm);

SmtpClient=new SmtpClient（）；
client.Port=587；
client.Host=“smtp.gmail.com”；
client.enablesl=true；
client.Timeout=10000；
client.DeliveryMethod=SmtpDeliveryMethod.Network；
client.UseDefaultCredentials=false；
client.Credentials=new System.Net.NetworkCredential（“@gmail.com”，”）；
MailMessage mm=新邮件消息（从地址文本到地址文本、消息主题、消息正文）；
mm.BodyEncoding=UTF8Encoding.UTF8；
mm.DeliveryNotificationOptions=DeliveryNotificationOptions.OnFailure；
客户端发送（mm）；
MailKit是一个开源的跨平台.NET邮件客户端库，它基于MimeKit并针对移动设备进行了优化。
它比System.Net.Mail具有更多和更高级的功能
通过MimeKit提供Microsoft TNEF支持

从下载nuget软件包

请参见此示例，您可以发送邮件

            MimeMessage mailMessage = new MimeMessage();
            mailMessage.From.Add(new MailboxAddress(senderName, sender@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());                
            }

这个答案的特点是：


尽可能使用“使用”（接口）
使用

将SmtpConfig提取到外部类（根据需要进行调整）

以下是提取的代码：

    public async Task SendAsync(string subject, string body, string to)
    {
        using (var message = new MailMessage(smtpConfig.FromAddress, to)
        {
            Subject = subject,
            Body = body,
            IsBodyHtml = true
        })
        {
            using (var client = new SmtpClient()
            {
                Port = smtpConfig.Port,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                UseDefaultCredentials = false,
                Host = smtpConfig.Host,
                Credentials = new NetworkCredential(smtpConfig.User, smtpConfig.Password),
            })
            {
                await client.SendMailAsync(message);
            }
        }                                     
    }

类SmtpConfig:

public class SmtpConfig
{
    public string Host { get; set; }
    public string User { get; set; }
    public string Password { get; set; }
    public int Port { get; set; }
    public string FromAddress { get; set; }
}

通过smtp发送电子邮件

public void EmailSend(string subject, string host, string from, string to, string body, int port, string username, string password, bool enableSsl)
    {
        try
        {
            MailMessage mail = new MailMessage();
            SmtpClient smtpServer = new SmtpClient(host);
            mail.Subject = subject;
            mail.From = new MailAddress(from);
            mail.To.Add(to);
            mail.Body = body;
            smtpServer.Port = port;
            smtpServer.Credentials = new NetworkCredential(username, password);
            smtpServer.EnableSsl = enableSsl;
            smtpServer.Send(mail);
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }

mail.To是只读的，from不是。publicmailaddresscollection到{get；}这是因为它是一个集合。您可以直接调用add toit@Oskar好吧，我应该说得更具体些。无法将mail.to设置为特定地址。必须使用构造函数或调用add。我只是在处理第一个编译器警告：错误CS0200:无法将属性或索引器'System.Net.Mail.MailMessage.To'分配给--它已被读取only@DougHauf可以将SmtpClient类与受密码保护的smtp服务器一起使用。您的smtp服务器似乎是一个内部服务器，这意味着您的程序只能在网络上连接到该smtp服务器
client.Host=“mail.youroutgoingsmtpserver.com”
client.Credentials=new System.Net.NetworkCredential（“您的用户名”、“您的密码”）SmtpClient实现IDisposable，因此您可能应该将其更改为：using（SmtpClient=new SmtpClient（））{…}不应该
            MimeMessage mailMessage = new MimeMessage();
            mailMessage.From.Add(new MailboxAddress(senderName, sender@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());                
            }

    public async Task SendAsync(string subject, string body, string to)
    {
        using (var message = new MailMessage(smtpConfig.FromAddress, to)
        {
            Subject = subject,
            Body = body,
            IsBodyHtml = true
        })
        {
            using (var client = new SmtpClient()
            {
                Port = smtpConfig.Port,
                DeliveryMethod = SmtpDeliveryMethod.Network,
                UseDefaultCredentials = false,
                Host = smtpConfig.Host,
                Credentials = new NetworkCredential(smtpConfig.User, smtpConfig.Password),
            })
            {
                await client.SendMailAsync(message);
            }
        }                                     
    }

public class SmtpConfig
{
    public string Host { get; set; }
    public string User { get; set; }
    public string Password { get; set; }
    public int Port { get; set; }
    public string FromAddress { get; set; }
}

public void EmailSend(string subject, string host, string from, string to, string body, int port, string username, string password, bool enableSsl)
    {
        try
        {
            MailMessage mail = new MailMessage();
            SmtpClient smtpServer = new SmtpClient(host);
            mail.Subject = subject;
            mail.From = new MailAddress(from);
            mail.To.Add(to);
            mail.Body = body;
            smtpServer.Port = port;
            smtpServer.Credentials = new NetworkCredential(username, password);
            smtpServer.EnableSsl = enableSsl;
            smtpServer.Send(mail);
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
    }