[英]C# Cannot resolve symbol
I don't know why I'm getting this error. 我不知道为什么会收到此错误。 Seems elementary. 似乎很基础。 Anyway I have a singleton class called EmailSender. 无论如何,我有一个名为EmailSender的单例类。 The code below is short and easy. 下面的代码简短易行。 The issue is that I can't use sender in the MainWindow class. 问题是我不能在MainWindow类中使用sender。 Anything I try such as sender.Send() is treated as though I've done asdafsafas.Send(). 我尝试过的任何操作(例如sender.Send())都被视为已完成asdafsafas.Send()。 It's treated as though it's a random string of characters. 它被视为随机字符串。 Don't know why this is happening. 不知道为什么会这样。
using System;
using System.Net.Mail;
using System.Windows.Forms;
namespace SendMail
{
public partial class MainWindow : Form
{
#region Private variables
private MailMessage msg = new MailMessage();
private EmailSender sender = EmailSender.GetInstance();
#endregion
public MainWindow()
{
InitializeComponent();
}
private MailMessage PrepareMailMessage()
{
return msg;
}
private void btnSend_Click(object sender, EventArgs e)
{
}
}
}
Here is the GetInstance method: 这是GetInstance方法:
public static EmailSender GetInstance()
{
return _instance ?? (_instance = new EmailSender());
}
This is because of the way you have this method defined (sender is a parameter). 这是因为您定义此方法的方式(发送者是参数)。 It's finding the method argument first , not your class level variable. 它首先找到方法参数,而不是您的类级别变量。 You can qualify this: 您可以符合以下条件:
private void btnSend_Click(object sender, EventArgs e)
{
// sender here is the "(object sender, " paramater, so it's defined
// as system object.
// use this instead:
this.sender.Send(); // The "this" will make the class find the instance level variable instead of using the "object sender" argument
}
That's because sender
is not a mail object, but rather the button that triggered the event. 这是因为sender
不是邮件对象,而是触发事件的按钮。 You need the SmtpClient
to send the email: 您需要SmtpClient
发送电子邮件:
private void btnSend_Click(object sender, EventArgs e)
{
SmtpClient client = new SmtpClient("192.0.0.1", 25); //host, port
client.Send(msg);
}
Also, the MailMessage
class implements IDisposable
, so you need some code to dispose of the message once you're done with it. 另外, MailMessage
类实现IDisposable
,因此使用完该消息后,您需要一些代码来处理该消息。
I created a wrapper that includes everything you need to send emails, including disposal: 我创建了一个包装程序,其中包含发送电子邮件所需的一切,包括处置:
/// <summary>
/// Wrapper class for the System.Net.Mail objects
/// </summary>
public class SmtpMailMessage : IDisposable
{
#region declarations
MailMessage Message;
SmtpClient SmtpMailClient;
#endregion
#region constructors
/// <summary>
/// Default constructor for the SmtpMailMessage class
/// </summary>
public SmtpMailMessage()
{
//initialize the mail message
Message = new MailMessage();
Message.Priority = MailPriority.Normal;
Message.DeliveryNotificationOptions = DeliveryNotificationOptions.OnFailure;
Message.From = new MailAddress("xxx@abc.com");
//initialize the smtp client
SmtpMailClient = new SmtpClient();
SmtpMailClient.DeliveryMethod = SmtpDeliveryMethod.Network;
SmtpMailClient.Host = "192.168.0.1";
SmtpMailClient.Port = 25;
}
/// <summary>
/// Parameterized constructor for the SmtpMailMessage class. Allows for override of the default
/// SMTP host and port number
/// </summary>
/// <param name="HostIP">The IP address of the exchange server</param>
/// <param name="PortNumber">The port number for ingoing and outgoing SMTP messages</param>
public SmtpMailMessage(string HostIP, int PortNumber) : this()
{
//override the smtp host value
SmtpMailClient.Host = HostIP;
//override the smtp port value
SmtpMailClient.Port = PortNumber;
}
#endregion
#region subject / body
/// <summary>
/// The body content of the mail message
/// </summary>
public string Body
{
get
{
return Message.Body;
}
set
{
Message.Body = value;
}
}
/// <summary>
/// the subject of the mail message
/// </summary>
public string Subject
{
get
{
return Message.Subject;
}
set
{
Message.Subject = value;
}
}
#endregion
#region mail type
/// <summary>
/// Gets or sets a value that determines whether the mail message
/// should be formatted as HTML or text
/// </summary>
public bool IsHtmlMessage
{
get
{
return Message.IsBodyHtml;
}
set
{
Message.IsBodyHtml = value;
}
}
#endregion
#region sender
/// <summary>
/// Gets or sets the from address of this message
/// </summary>
public string From
{
get
{
return Message.From.Address;
}
set
{
Message.From = new MailAddress(value);
}
}
#endregion
#region recipients
/// <summary>
/// Gets the collection of recipients
/// </summary>
public MailAddressCollection To
{
get
{
return Message.To;
}
}
/// <summary>
/// Gets the collection of CC recipients
/// </summary>
public MailAddressCollection CC
{
get
{
return Message.CC;
}
}
/// <summary>
/// Gets the collection of Bcc recipients
/// </summary>
public MailAddressCollection Bcc
{
get
{
return Message.Bcc;
}
}
#endregion
#region delivery notification
/// <summary>
/// Gets or sets the delivery notification settings for this message
/// </summary>
public DeliveryNotificationOptions DeliveryNotifications
{
get
{
return Message.DeliveryNotificationOptions;
}
set
{
Message.DeliveryNotificationOptions = value;
}
}
#endregion
#region priority
/// <summary>
/// Gets or sets the Priority of this message
/// </summary>
public MailPriority PriorityLevel
{
get
{
return Message.Priority;
}
set
{
Message.Priority = value;
}
}
#endregion
#region send methods
/// <summary>
/// Sends the message anonymously (without credentials)
/// </summary>
public void Send()
{
SmtpMailClient.Send(Message);
}
/// <summary>
/// Sends the message with authorization from a network account
/// </summary>
/// <param name="Username">The Windows username of the authorizing user</param>
/// <param name="Password">The Windows password of the authorizing user</param>
/// <param name="Domain">The domain name of the network to which the authorizing user belongs</param>
public void Send(string Username, string Password, string Domain)
{
//attach a network credential to this message using the information passed into the method
SmtpMailClient.Credentials = new NetworkCredential(Username, Password, Domain);
//send the message
SmtpMailClient.Send(Message);
}
#endregion
#region IDisposable implementation
~SmtpMailMessage()
{
Dispose(false);
}
public void Dispose()
{
Dispose(true);
}
protected virtual void Dispose(bool disposing)
{
if (disposing)
{
if (Message != null)
Message.Dispose();
Message = null;
SmtpMailClient = null;
}
}
#endregion
}
Implementation: 实现方式:
using (SmtpMailMessage mail = new SmtpMailMessage("192.168.0.1", 25))
{
//set the to address to the primary email
mail.To.Add("xxx@abc.com");
//set the message type and subject and body
mail.IsHtmlMessage = true;
mail.Subject = "Foo";
mail.Body = "Hello world!";
//send the email
mail.Send();
}
If you're doing it inside the scope of your btnSend_Click
method, the parameter object sender
takes precedence over the global EmailSender sender
. 如果您在btnSend_Click
方法的范围内执行此操作,则参数object sender
优先于全局EmailSender sender
。
You should either rename your global variable, eg: EmailSender m_sender
or specify exactly which sender you want: this.sender.Send()
您应该重命名全局变量,例如: EmailSender m_sender
或确切指定所需的发送者: this.sender.Send()
I guess you call the sender.Send in the btnSend_Click function. 我猜你叫btnSend_Click函数中的sender.Send。
In that function is a param also called sender (object sender). 在该函数中有一个参数,也称为发送者(对象发送者)。 Now you code is confused which one to use. 现在,您对使用哪个代码感到困惑。 So rename your private var sender. 因此,重命名您的私人var发送者。
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.