如何注射ILogger <T> 依賴於ConfigureServices中的服務 - .net core 2.0

Question

我有以下MailService ：

public class MailService : IMailService
{
    private readonly ILogger<MailService> _logger;
    private readonly SmtpClient _client;

    public MailService(ILogger<MailService> logger, SmtpClient client)
    {
        _logger = logger;
        _client = client;
    }

    public async Task Send(string to, string subject, string body)
    {
        var message = new MailMessage
        {
            Subject = subject,
            Body = body,
            IsBodyHtml = true,
            From = new MailAddress("info@domain.com")
        };

        message.To.Add(to);

        using (_client)
        {
            _logger.LogTrace($"Sending email from {message.From.Address} to {to}. Subject: {subject}");
            await _client.SendMailAsync(message);
        }
    }

}

我想使用實現工廠創建此服務，因為我將從配置中讀取smtp設置並提供smtp客戶端，如Startup.cs的以下內容：

services.AddTransient<IMailService>(provider =>
{
    var mailService = new MailService(***LOGGER INSTANCE HERE***, new SmtpClient("127.0.0.1", 25));
    return mailService;
});

有沒有辦法獲取記錄器實例並將其提供給郵件服務？

Answer 1

我想使用實現工廠創建此服務，因為我將從配置中讀取smtp設置並提供smtp客戶端

你不應該用實現工廠添加IMailService ，最好用實現工廠添加SmtpClient

services.AddTransient<IMailService, MailService>();
services.AddTransient(_ => new SmtpClient("127.0.0.1", 25));

Answer 2

這不行嗎？

services.AddTransient<IMailService>(provider =>

        {
            return new MailService(provider.GetRequiredService<ILogger<MailService>>(), new SmtpClient());
        });