使用 NetCore.MailKit 发送电子邮件时地址的 ArgumentNullException

Question

我正在使用NetCore.MailKitNuGet包来帮助我发送一封电子邮件，其中包含一个链接，用于在用户注册时确认其电子邮件。我已经按照他们的 Github 页面上的步骤进行操作，但是，即使我已经设置了发送地址，我也得到了地址ArgumentNullException。

错误：

ArgumentNullException: Value cannot be null. (Parameter 'address')
MimeKit.MailboxAddress..ctor(Encoding encoding, string name, string address)

使用 IEmailService 在我的控制器中发送电子邮件时，会发生上述错误：

_EmailService.Send("[e-mail]", "subject", "message body");

这是我appsettings.json配置：

"EmailConfiguration": {
"Server": "smtp.gmail.com",
"Port": 587,
"SenderName": "name",
"SenderEmail": "[e-mail]",
"SenderPassword": "My gmail password"
}

这是我在startup.cs中的设置

services.AddMailKit(optionBuilder =>
{
optionBuilder.UseMailKit(new MailKitOptions()
{
//get options from sercets.json
Server = Configuration["Server"],
Port = Convert.ToInt32(Configuration["Port"]),
SenderName = Configuration["SenderName"],
SenderEmail = Configuration["SenderEmail"],
Account = Configuration["SenderEmail"],
Password = Configuration["SenderPassword"],
Security = true
});
});

以下是电子邮件服务的代码：

public void Send(string mailTo, string subject, string message, bool isHtml = false)
{
SendEmail(mailTo, null, null, subject, message, Encoding.UTF8, isHtml);
}
private void SendEmail(string mailTo, string mailCc, string mailBcc, string subject, string message, Encoding encoding, bool isHtml)
{
var _to = new string[0];
var _cc = new string[0];
var _bcc = new string[0];
if (!string.IsNullOrEmpty(mailTo))
_to = mailTo.Split(',').Select(x => x.Trim()).ToArray();
if (!string.IsNullOrEmpty(mailCc))
_cc = mailCc.Split(',').Select(x => x.Trim()).ToArray();
if (!string.IsNullOrEmpty(mailBcc))
_bcc = mailBcc.Split(',').Select(x => x.Trim()).ToArray();
Check.Argument.IsNotEmpty(_to, nameof(mailTo));
Check.Argument.IsNotEmpty(message, nameof(message));
var mimeMessage = new MimeMessage();
//add mail from
mimeMessage.From.Add(new MailboxAddress(_MailKitProvider.Options.SenderName, _MailKitProvider.Options.SenderEmail));
//add mail to 
foreach (var to in _to)
{
mimeMessage.To.Add(MailboxAddress.Parse(to));
}
//add mail cc
foreach (var cc in _cc)
{
mimeMessage.Cc.Add(MailboxAddress.Parse(cc));
}
//add mail bcc 
foreach (var bcc in _bcc)
{
mimeMessage.Bcc.Add(MailboxAddress.Parse(bcc));
}
//add subject
mimeMessage.Subject = subject;
//add email body
TextPart body = null;
if (isHtml)
{
body = new TextPart(TextFormat.Html);
}
else
{
body = new TextPart(TextFormat.Text);
}
//set email encoding
body.SetText(encoding, message);
//set email body
mimeMessage.Body = body;
using (var client = _MailKitProvider.SmtpClient)
{
client.Send(mimeMessage);
}
}

如您所见，我已经设置了所有内容，我在这里错过了什么吗？ 为什么地址在MimeKit.MailboxAddress()为空？

Answer 1

您似乎没有正确加载配置设置。我怀疑您的代码中的失败行是

//add mail from
mimeMessage.From.Add(new MailboxAddress(_MailKitProvider.Options.SenderName, _MailKitProvider.Options.SenderEmail));

选项均为空，这会导致异常。

从配置文件加载设置时，需要在变量前面附加节名称。例如

services.AddMailKit(optionBuilder =>
{
optionBuilder.UseMailKit(new MailKitOptions()
{
//get options from sercets.json
Server = Configuration["EmailConfiguration:Server"],
Port = Convert.ToInt32(Configuration["EmailConfiguration:Port"]),
SenderName = Configuration["EmailConfiguration:SenderName"],
SenderEmail = Configuration["EmailConfiguration:SenderEmail"],
Account = Configuration["EmailConfiguration:SenderEmail"],
Password = Configuration["EmailConfiguration:SenderPassword"],
Security = true
});
});

Answer 2

我的猜测是异常被抛在以下行：

mimeMessage.From.Add(new MailboxAddress(_MailKitProvider.Options.SenderName, _MailKitProvider.Options.SenderEmail));

这意味着_MailKitProvider.Options.SenderEmail是null.

我知道您希望从 appsettings.json 文件中正确加载这些值，但似乎由于某种原因没有加载它们。