Can't return completedsuccesfull task in .net core - .net-core

Question

Hi I wrote the following code:
private bool GetIsCompleted()
{
return Email.SendMessageAsync().IsCompletedSuccessfully;
}
[HttpPost]
public ViewResult CheckOut(Order order)
{
if (Cart.Lines.Count() == 0)
{
ModelState.AddModelError("","Your Cart is empty!");
}
if (ModelState.IsValid)
{
order.CartLines = Cart.Lines;
order.DateTime = DateTime.Now;
order.TotalPrice = Cart.ComputeTotalValue();
if (Repository.SaveOrder(order))
{
if (User.Identity.Name != null)
{
Email.SetMessageBody(order.OrderID);
if (GetIsCompleted())
{
Cart.Clear();
return View("Completed");
}
}
}
ViewBag.Error = "An error Occured while sending you an email with the order details.";
return View(new Order());
}
else
{
ViewBag.Error = "An error Occured while trying to save your order. Please try again!";
return View(new Order());
}
}
public async Task SendMessageAsync()
{
this.Message = new MailMessage(this.MailFrom.ToString(), this.MailTo.ToString(), this.GetSubject(), this.GetMessageBody());
//Message.Dispose();
try
{
await this.Client.SendMailAsync(this.Message);
}
catch (Exception ex)
{
Logger.LogInformation("The Email couldn't send to the recipient");
}
}
I get
An error Occured while sending you an email with the order details.
in the View. I want GetIsCompleted() to return true to proceed the code. It is developed under .net core. I do not understand why IsCompletedSuccessfully() does not return true; Any suggestion?

Answer 1

The current flow of your code is this:
Start sending the e-mail.
Check if it is completed successfully, decide that it hasn't and return failure.
The e-mail completes sending.
You're awaiting the actual SendMailAsync(..) method, and that's great, but nothing awaits SendMessageAsync(...) so it immediately returns the incomplete task to the caller. Because there isn't enough time between starting to send the e-mail and checking if the task completed, the status will be false.
You need to use async all the way up. Change your method definition to be async:
public async Task<ViewResult> CheckOut(Order order)
Replace this code:
if (GetIsCompleted())
{
Cart.Clear();
return View("Completed");
}
with this:
try
{
await Email.SendMessageAsync();
Cart.Clear();
return View("Completed");
}
catch (Exception e)
{
// handle exception
}
It's worth noting that you'll only ever get an exception if the call to new MailMessage(...) fails because your try/catch block in SendMessageAsync is swallowing all other exceptions.