diff --git a/framework/src/Volo.Abp.EventBus.Azure/Volo/Abp/EventBus/Azure/AzureDistributedEventBus.cs b/framework/src/Volo.Abp.EventBus.Azure/Volo/Abp/EventBus/Azure/AzureDistributedEventBus.cs
index 100d2d9942..8279a412a5 100644
--- a/framework/src/Volo.Abp.EventBus.Azure/Volo/Abp/EventBus/Azure/AzureDistributedEventBus.cs
+++ b/framework/src/Volo.Abp.EventBus.Azure/Volo/Abp/EventBus/Azure/AzureDistributedEventBus.cs
@@ -22,13 +22,13 @@ namespace Volo.Abp.EventBus.Azure;
 [ExposeServices(typeof(IDistributedEventBus), typeof(AzureDistributedEventBus))]
 public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDependency
 {
-    private readonly AbpAzureEventBusOptions _options;
-    private readonly IAzureServiceBusMessageConsumerFactory _messageConsumerFactory;
-    private readonly IPublisherPool _publisherPool;
-    private readonly IAzureServiceBusSerializer _serializer;
-    private readonly ConcurrentDictionary<Type, List<IEventHandlerFactory>> _handlerFactories;
-    private readonly ConcurrentDictionary<string, Type> _eventTypes;
-    private IAzureServiceBusMessageConsumer _consumer;
+    protected AbpAzureEventBusOptions Options { get; }
+    protected IAzureServiceBusMessageConsumerFactory MessageConsumerFactory { get; }
+    protected IPublisherPool PublisherPool { get; }
+    protected IAzureServiceBusSerializer Serializer { get; }
+    protected ConcurrentDictionary<Type, List<IEventHandlerFactory>> HandlerFactories { get; }
+    protected ConcurrentDictionary<string, Type> EventTypes  { get; }
+    protected IAzureServiceBusMessageConsumer Consumer  { get; private set; }
 
     public AzureDistributedEventBus(
         IServiceScopeFactory serviceScopeFactory,
@@ -52,22 +52,22 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
             eventHandlerInvoker,
             localEventBus)
     {
-        _options = abpAzureEventBusOptions.Value;
-        _serializer = serializer;
-        _messageConsumerFactory = messageConsumerFactory;
-        _publisherPool = publisherPool;
-        _handlerFactories = new ConcurrentDictionary<Type, List<IEventHandlerFactory>>();
-        _eventTypes = new ConcurrentDictionary<string, Type>();
+        Options = abpAzureEventBusOptions.Value;
+        Serializer = serializer;
+        MessageConsumerFactory = messageConsumerFactory;
+        PublisherPool = publisherPool;
+        HandlerFactories = new ConcurrentDictionary<Type, List<IEventHandlerFactory>>();
+        EventTypes = new ConcurrentDictionary<string, Type>();
     }
 
     public void Initialize()
     {
-        _consumer = _messageConsumerFactory.CreateMessageConsumer(
-            _options.TopicName,
-            _options.SubscriberName,
-            _options.ConnectionName);
+        Consumer = MessageConsumerFactory.CreateMessageConsumer(
+            Options.TopicName,
+            Options.SubscriberName,
+            Options.ConnectionName);
 
-        _consumer.OnMessageReceived(ProcessEventAsync);
+        Consumer.OnMessageReceived(ProcessEventAsync);
         SubscribeHandlers(AbpDistributedEventBusOptions.Handlers);
     }
 
@@ -78,13 +78,13 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
         {
             return;
         }
-        var eventType = _eventTypes.GetOrDefault(eventName);
+        var eventType = EventTypes.GetOrDefault(eventName);
         if (eventType == null)
         {
             return;
         }
 
-        var eventData = _serializer.Deserialize(message.Body.ToArray(), eventType);
+        var eventData = Serializer.Deserialize(message.Body.ToArray(), eventType);
 
         if (await AddToInboxAsync(message.MessageId, eventName, eventType, eventData))
         {
@@ -110,9 +110,9 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
     {
         var outgoingEventArray =  outgoingEvents.ToArray();
 
-        var publisher = await _publisherPool.GetAsync(
-            _options.TopicName,
-            _options.ConnectionName);
+        var publisher = await PublisherPool.GetAsync(
+            Options.TopicName,
+            Options.ConnectionName);
 
         using var messageBatch = await publisher.CreateMessageBatchAsync();
 
@@ -144,13 +144,13 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
 
     public async override Task ProcessFromInboxAsync(IncomingEventInfo incomingEvent, InboxConfig inboxConfig)
     {
-        var eventType = _eventTypes.GetOrDefault(incomingEvent.EventName);
+        var eventType = EventTypes.GetOrDefault(incomingEvent.EventName);
         if (eventType == null)
         {
             return;
         }
 
-        var eventData = _serializer.Deserialize(incomingEvent.EventData, eventType);
+        var eventData = Serializer.Deserialize(incomingEvent.EventData, eventType);
         var exceptions = new List<Exception>();
         await TriggerHandlersFromInboxAsync(eventType, eventData, exceptions, inboxConfig);
         if (exceptions.Any())
@@ -161,7 +161,7 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
 
     protected override byte[] Serialize(object eventData)
     {
-        return _serializer.Serialize(eventData);
+        return Serializer.Serialize(eventData);
     }
 
     public override IDisposable Subscribe(Type eventType, IEventHandlerFactory factory)
@@ -242,7 +242,7 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
 
     protected virtual Task PublishAsync(string eventName, object eventData)
     {
-        var body = _serializer.Serialize(eventData);
+        var body = Serializer.Serialize(eventData);
 
         return PublishAsync(eventName, body, null);
     }
@@ -262,16 +262,16 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
             message.MessageId = (eventId ?? GuidGenerator.Create()).ToString("N");
         }
 
-        var publisher = await _publisherPool.GetAsync(
-            _options.TopicName,
-            _options.ConnectionName);
+        var publisher = await PublisherPool.GetAsync(
+            Options.TopicName,
+            Options.ConnectionName);
 
         await publisher.SendMessageAsync(message);
     }
 
     protected override IEnumerable<EventTypeWithEventHandlerFactories> GetHandlerFactories(Type eventType)
     {
-        return _handlerFactories
+        return HandlerFactories
             .Where(hf => ShouldTriggerEventForHandler(eventType, hf.Key))
             .Select(handlerFactory =>
                 new EventTypeWithEventHandlerFactories(handlerFactory.Key, handlerFactory.Value))
@@ -283,14 +283,20 @@ public class AzureDistributedEventBus : DistributedEventBusBase, ISingletonDepen
         return handlerEventType == targetEventType || handlerEventType.IsAssignableFrom(targetEventType);
     }
 
+    protected override Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        EventTypes.GetOrAdd(eventName, eventType);
+        return base.OnAddToOutboxAsync(eventName, eventType, eventData);
+    }
+
     private List<IEventHandlerFactory> GetOrCreateHandlerFactories(Type eventType)
     {
-        return _handlerFactories.GetOrAdd(
+        return HandlerFactories.GetOrAdd(
             eventType,
             type =>
             {
                 var eventName = EventNameAttribute.GetNameOrDefault(type);
-                _eventTypes[eventName] = type;
+                EventTypes.GetOrAdd(eventName, eventType);
                 return new List<IEventHandlerFactory>();
             }
         );
diff --git a/framework/src/Volo.Abp.EventBus.Dapr/Volo/Abp/EventBus/Dapr/DaprDistributedEventBus.cs b/framework/src/Volo.Abp.EventBus.Dapr/Volo/Abp/EventBus/Dapr/DaprDistributedEventBus.cs
index 28077ad43e..23cf8aa1e9 100644
--- a/framework/src/Volo.Abp.EventBus.Dapr/Volo/Abp/EventBus/Dapr/DaprDistributedEventBus.cs
+++ b/framework/src/Volo.Abp.EventBus.Dapr/Volo/Abp/EventBus/Dapr/DaprDistributedEventBus.cs
@@ -165,6 +165,7 @@ public class DaprDistributedEventBus : DistributedEventBusBase, ISingletonDepend
                 EventName = outgoingEvent.EventName,
                 EventData = outgoingEvent.EventData
             });
+
             await PublishToDaprAsync(outgoingEvent.EventName, Serializer.Deserialize(outgoingEvent.EventData, GetEventType(outgoingEvent.EventName)));
         }
     }
@@ -201,6 +202,12 @@ public class DaprDistributedEventBus : DistributedEventBusBase, ISingletonDepend
         return Serializer.Serialize(eventData);
     }
 
+    protected override Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        EventTypes.GetOrAdd(eventName, eventType);
+        return base.OnAddToOutboxAsync(eventName, eventType, eventData);
+    }
+
     private List<IEventHandlerFactory> GetOrCreateHandlerFactories(Type eventType)
     {
         return HandlerFactories.GetOrAdd(
@@ -208,7 +215,7 @@ public class DaprDistributedEventBus : DistributedEventBusBase, ISingletonDepend
             type =>
             {
                 var eventName = EventNameAttribute.GetNameOrDefault(type);
-                EventTypes[eventName] = type;
+                EventTypes.GetOrAdd(eventName, eventType);
                 return new List<IEventHandlerFactory>();
             }
         );
diff --git a/framework/src/Volo.Abp.EventBus.Kafka/Volo/Abp/EventBus/Kafka/KafkaDistributedEventBus.cs b/framework/src/Volo.Abp.EventBus.Kafka/Volo/Abp/EventBus/Kafka/KafkaDistributedEventBus.cs
index 057b081ad8..62e161fad1 100644
--- a/framework/src/Volo.Abp.EventBus.Kafka/Volo/Abp/EventBus/Kafka/KafkaDistributedEventBus.cs
+++ b/framework/src/Volo.Abp.EventBus.Kafka/Volo/Abp/EventBus/Kafka/KafkaDistributedEventBus.cs
@@ -282,6 +282,12 @@ public class KafkaDistributedEventBus : DistributedEventBusBase, ISingletonDepen
             });
     }
 
+    protected override Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        EventTypes.GetOrAdd(eventName, eventType);
+        return base.OnAddToOutboxAsync(eventName, eventType, eventData);
+    }
+
     private List<IEventHandlerFactory> GetOrCreateHandlerFactories(Type eventType)
     {
         return HandlerFactories.GetOrAdd(
@@ -289,7 +295,7 @@ public class KafkaDistributedEventBus : DistributedEventBusBase, ISingletonDepen
             type =>
             {
                 var eventName = EventNameAttribute.GetNameOrDefault(type);
-                EventTypes[eventName] = type;
+                EventTypes.GetOrAdd(eventName, eventType);
                 return new List<IEventHandlerFactory>();
             }
         );
diff --git a/framework/src/Volo.Abp.EventBus.RabbitMQ/Volo/Abp/EventBus/RabbitMq/RabbitMqDistributedEventBus.cs b/framework/src/Volo.Abp.EventBus.RabbitMQ/Volo/Abp/EventBus/RabbitMq/RabbitMqDistributedEventBus.cs
index 050f730dba..8d4756165a 100644
--- a/framework/src/Volo.Abp.EventBus.RabbitMQ/Volo/Abp/EventBus/RabbitMq/RabbitMqDistributedEventBus.cs
+++ b/framework/src/Volo.Abp.EventBus.RabbitMQ/Volo/Abp/EventBus/RabbitMq/RabbitMqDistributedEventBus.cs
@@ -358,6 +358,12 @@ public class RabbitMqDistributedEventBus : DistributedEventBusBase, ISingletonDe
         }
     }
 
+    protected override Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        EventTypes.GetOrAdd(eventName, eventType);
+        return base.OnAddToOutboxAsync(eventName, eventType, eventData);
+    }
+
     private List<IEventHandlerFactory> GetOrCreateHandlerFactories(Type eventType)
     {
         return HandlerFactories.GetOrAdd(
@@ -365,7 +371,7 @@ public class RabbitMqDistributedEventBus : DistributedEventBusBase, ISingletonDe
             type =>
             {
                 var eventName = EventNameAttribute.GetNameOrDefault(type);
-                EventTypes[eventName] = type;
+                EventTypes.GetOrAdd(eventName, eventType);
                 return new List<IEventHandlerFactory>();
             }
         );
diff --git a/framework/src/Volo.Abp.EventBus.Rebus/Volo/Abp/EventBus/Rebus/RebusDistributedEventBus.cs b/framework/src/Volo.Abp.EventBus.Rebus/Volo/Abp/EventBus/Rebus/RebusDistributedEventBus.cs
index befc734aa3..0983e98836 100644
--- a/framework/src/Volo.Abp.EventBus.Rebus/Volo/Abp/EventBus/Rebus/RebusDistributedEventBus.cs
+++ b/framework/src/Volo.Abp.EventBus.Rebus/Volo/Abp/EventBus/Rebus/RebusDistributedEventBus.cs
@@ -184,6 +184,12 @@ public class RebusDistributedEventBus : DistributedEventBusBase, ISingletonDepen
         unitOfWork.AddOrReplaceDistributedEvent(eventRecord);
     }
 
+    protected override Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        EventTypes.GetOrAdd(eventName, eventType);
+        return base.OnAddToOutboxAsync(eventName, eventType, eventData);
+    }
+
     private List<IEventHandlerFactory> GetOrCreateHandlerFactories(Type eventType)
     {
         return HandlerFactories.GetOrAdd(
@@ -191,7 +197,7 @@ public class RebusDistributedEventBus : DistributedEventBusBase, ISingletonDepen
             type =>
             {
                 var eventName = EventNameAttribute.GetNameOrDefault(type);
-                EventTypes[eventName] = type;
+                EventTypes.GetOrAdd(eventName, eventType);
                 return new List<IEventHandlerFactory>();
             }
         );
diff --git a/framework/src/Volo.Abp.EventBus/Volo/Abp/EventBus/Distributed/DistributedEventBusBase.cs b/framework/src/Volo.Abp.EventBus/Volo/Abp/EventBus/Distributed/DistributedEventBusBase.cs
index 871fb9459f..89423ce111 100644
--- a/framework/src/Volo.Abp.EventBus/Volo/Abp/EventBus/Distributed/DistributedEventBusBase.cs
+++ b/framework/src/Volo.Abp.EventBus/Volo/Abp/EventBus/Distributed/DistributedEventBusBase.cs
@@ -105,7 +105,7 @@ public abstract class DistributedEventBusBase : EventBusBase, IDistributedEventB
         IncomingEventInfo incomingEvent,
         InboxConfig inboxConfig);
 
-    private async Task<bool> AddToOutboxAsync(Type eventType, object eventData)
+    protected virtual async Task<bool> AddToOutboxAsync(Type eventType, object eventData)
     {
         var unitOfWork = UnitOfWorkManager.Current;
         if (unitOfWork == null)
@@ -117,10 +117,11 @@ public abstract class DistributedEventBusBase : EventBusBase, IDistributedEventB
         {
             if (outboxConfig.Selector == null || outboxConfig.Selector(eventType))
             {
-                var eventOutbox =
-                    (IEventOutbox)unitOfWork.ServiceProvider.GetRequiredService(outboxConfig.ImplementationType);
+                var eventOutbox = (IEventOutbox)unitOfWork.ServiceProvider.GetRequiredService(outboxConfig.ImplementationType);
                 var eventName = EventNameAttribute.GetNameOrDefault(eventType);
 
+                await OnAddToOutboxAsync(eventName, eventType, eventData);
+
                 await TriggerDistributedEventSentAsync(new DistributedEventSent()
                 {
                     Source = DistributedEventSource.Direct,
@@ -143,6 +144,11 @@ public abstract class DistributedEventBusBase : EventBusBase, IDistributedEventB
         return false;
     }
 
+    protected virtual Task OnAddToOutboxAsync(string eventName, Type eventType, object eventData)
+    {
+        return Task.CompletedTask;
+    }
+
     protected async Task<bool> AddToInboxAsync(
         string messageId,
         string eventName,