在 .net 核心中将 MailMessage 转换为 MemoryStream

Question

我正在使用带有 Amazon SES（SimpleEmail）的 .Net Core 1.2 来发送电子邮件（原始电子邮件）。

下面是我们在.net framework 4.5中使用的工作代码版本：

   public MemoryStream ConvertMailMessageToMemoryStream(MailMessage message)
    {
        Assembly assembly = typeof(SmtpClient).Assembly;

        Type mailWriterType = assembly.GetType("System.Net.Mail.MailWriter");

        MemoryStream fileStream = new MemoryStream();

        ConstructorInfo mailWriterContructor = mailWriterType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(Stream) }, null);

        object mailWriter = mailWriterContructor.Invoke(new object[] { fileStream });

        MethodInfo sendMethod = typeof(MailMessage).GetMethod("Send", BindingFlags.Instance | BindingFlags.NonPublic);

        sendMethod.Invoke(message, BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { mailWriter, true, true }, null);

        MethodInfo closeMethod = mailWriter.GetType().GetMethod("Close", BindingFlags.Instance | BindingFlags.NonPublic);

        closeMethod.Invoke(mailWriter, BindingFlags.Instance | BindingFlags.NonPublic, null, new object[] { }, null);

        return fileStream;

    }

但在 .Net Core 1.2 中，我们无法获取 SmtpClient 和 System.Net.Mail.MailWriter 类 Assembly 的参考。以下是在常规 .net 框架中工作：

Assembly assembly = typeof(SmtpClient).Assembly;

在.Net Core中，由于MailKit中提供了SmtpClient，我们引用了它并给出如下错误：

'Type' does not contain a definition for 'Assembly' and no extension method 'Assembly' accepting a first argument of type 'Type' could be found (are you missing a using directive or an assembly reference?)

.Net Core 中有什么方法可以将 MailMessage 转换为 MemoryStream 吗？

Answer 1

在 dotnet core 5.0 中似乎没有构造函数只接受一个参数，试试这个。

ConstructorInfo mailWriterContructor = mailWriterType.GetConstructor(BindingFlags.Instance | BindingFlags.NonPublic, null, new[] { typeof(Stream), typeof(bool) }, null);

    object mailWriter = mailWriterContructor.Invoke(new object[] { fileStream,true });

Answer 2

**试试这个**

 private static string ConvertMailMessageToMemoryStream(MailMessage message)
    {
        BindingFlags flags = BindingFlags.Instance | BindingFlags.NonPublic;
        Assembly assembly = typeof(SmtpClient).Assembly;
        Type mailWriterType = assembly.GetType("System.Net.Mail.MailWriter");
        MemoryStream stream = new MemoryStream();
        ConstructorInfo mailWriterConstructor = mailWriterType.GetConstructor(flags, null, new[] { typeof(Stream) }, null);
        object mailWriter = mailWriterConstructor.Invoke(new object[] { stream });
        MethodInfo sendMethod = typeof(MailMessage).GetMethod("Send", flags);
        sendMethod.Invoke(message, flags, null, new[] { mailWriter, true, true }, null);
        var sr = new StreamReader(stream);
        var str = sr.ReadToEnd();
        MethodInfo closeMethod = mailWriter.GetType().GetMethod("Close", flags);
        closeMethod.Invoke(mailWriter, flags, null, new object[] { }, null);
        return str;
    }