Asp.Net Identity 2.0(MVC5)中能否安全弃用UserManager.SendEmailAsync？

Absolutely, you can safely ignore and bypass UserManager.SendEmailAsync—this is a common, valid approach when the default email implementation is too limited for your needs. Here’s a practical breakdown of how to pull this off cleanly:

Why ignoring it is safe #

The UserManager.SendEmailAsync method is just a convenience wrapper that delegates to an IIdentityMessageService implementation (like the default template EmailService). None of Identity’s core functionality—user creation, authentication, role management—depends on this method. It only runs when your code explicitly calls it (for example, in the default "forgot password" or "account confirmation" flows). As long as you replace those explicit calls with your custom service, you won’t break any core Identity features.

How to replace the default email flow #

1. Build your standalone email service
   Create a separate assembly with a clear service interface (e.g., IUserNotificationService) that exposes methods like ScheduleMessage(int userId, MessageKindEnum messageKind). This service will handle all the details you care about:

   • Fetching user details (email, username) from your data store
   • Rendering HTML templates (use a library like RazorEngine or a custom template system for dynamic content)
   • Sending emails via a robust client (MailKit is a far better alternative to the outdated SmtpClient)
   • Optional async scheduling (use tools like Hangfire to queue emails for background delivery and avoid blocking user interactions)

2. Replace default calls to SendEmailAsync
   Go through your codebase to find where UserManager.SendEmailAsync is being used (like in the default AccountController’s ForgotPassword or ConfirmEmail actions) and swap those calls with your custom service. For example:

   // Old default code
   // await UserManager.SendEmailAsync(userId, "Reset Password", resetLink);
   
   // New custom service call
   await _userNotificationService.ScheduleMessage(userId, MessageKindEnum.PasswordReset);
   

3. Clean up unused dependencies
   If you registered an IIdentityMessageService implementation in your startup code, you can remove that registration entirely. Since you’re no longer relying on UserManager.SendEmailAsync, this won’t impact your app at all.

Pro tips for a smooth transition #

• Keep your service decoupled: Inject dependencies like your user database context or template renderer via DI, making the service easy to test and maintain.
• Handle edge cases: Add error handling for scenarios like missing user emails, template rendering failures, or email delivery errors—log these issues so you can debug them later.
• Validate end-to-end: Test all email-triggering flows (password reset, account confirmation, custom notifications) to ensure they work as expected with your new service.

内容的提问来源于stack exchange，提问作者Diana