在.NET Core 1.0 中，SMTP Client代码并没有被移植，直到.NET Core 2.0的发布。使用下面的代码：
static void Main(string[] args)
{
SmtpClient client = new SmtpClient("smtp.163.com");
client.UseDefaultCredentials = false;
client.Credentials = new NetworkCredential("bidianqing123", "your password");
MailMessage mailMessage = new MailMessage();
mailMessage.From = new MailAddress("bidianqing123@163.com");
mailMessage.To.Add("bidianqing@qq.com");
mailMessage.Body = "body";
mailMessage.Subject = "subject";
client.Send(mailMessage);
Console.WriteLine("发送成功");
Console.ReadKey();
}
一定要确保框架是.NET Core 2.0，否则你将无法使用它。
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<OutputType>Exe</OutputType>
<TargetFramework>netcoreapp2.0</TargetFramework>
</PropertyGroup>
</Project>