我想在控制台应用程序中使用 smtp 一次发送多个 email 请求。如何使用线程一次发送批量 email 请求

Question

for (int i = 0; i < 50; i++)
{
    Thread T1 = new Thread(delegate ()
    {
            Console.WriteLine("email sent..");
            smtp.Send(msg);
    });
    T1.Start();
}                       

I am trying to send bulk request with multithreading using smtp.Send(msg).

I have tried the code above but I am getting this error

An asynchronous call is already in progress. It must be completed or canceled before you can call this method

How I can resolve this.

Answer 1

If you are using following client . I would recommend you refactor your code like following:

var tasks = new List<Task>()
for (int i = 0; i < 50; i++)
{
    task.Add(smtp.SendAsync(msg));
}
await Task.WhenAll(tasks)

What's the difference?

Using tasks will use Threads in the background but will take care of all the thread scheduling and cleanup. c# TPL is the way to go if you want to add parallelism and concurrency to your application applications (I stole that line from above link)

Taking into account @phuzi comment on your question it can be that you need to instantiate a client inside your for loop.

Bare in mind that this will use await for you'll have to add async to your function signature.