Convert MailMessage to MemoryStream in .net core - amazon-ses

Question

I am using the .Net Core 1.2 with Amazon SES(SimpleEmail) to send the Emails(Raw Emails).
Below is the working code version we have used in .net framework 4.5:
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;
}
But in .Net Core 1.2 we are unable to get reference for class Assembly of SmtpClient and System.Net.Mail.MailWriter. Below is working in regular .net framework:
Assembly assembly = typeof(SmtpClient).Assembly;
In .Net Core, since SmtpClient is available in MailKit, we have referenced it and gives the following error:
'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?)
Is there any way in .Net Core to convert the MailMessage to MemoryStream?

Answer 1

Looks like there is no constructor accepting only one argument in dotnet core 5.0, try this.
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

** try this**
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;
}