Register NullSmsSender as TryRegister

framework/src/Volo.Abp.Sms/Volo/Abp/Sms/ISmsSender.cs

@@ -1,5 +1,4 @@
-using System.Collections.Generic;
-using System.Threading.Tasks;
+using System.Threading.Tasks;
 
 namespace Volo.Abp.Sms
 {

framework/src/Volo.Abp.Sms/Volo/Abp/Sms/NullSmsSender.cs

@@ -1,11 +1,11 @@
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Logging.Abstractions;
-using System.Collections.Generic;
 using System.Threading.Tasks;
 using Volo.Abp.DependencyInjection;
 
 namespace Volo.Abp.Sms
 {
+    [Dependency(TryRegister = true)]
     public class NullSmsSender : ISmsSender, ISingletonDependency
     {
         public ILogger<NullSmsSender> Logger { get; set; }
@@ -18,6 +18,7 @@ namespace Volo.Abp.Sms
         public Task SendAsync(SmsMessage smsMessage)
         {
             Logger.LogWarning($"SMS Sending was not implemented! Using {nameof(NullSmsSender)}:");
+
             Logger.LogWarning("Phone Number : " + smsMessage.PhoneNumber);
             Logger.LogWarning("SMS Text     : " + smsMessage.Text);