解决RabbitMQ没有连接就获取通道的bug

Admin.NET/Admin.NET.Core/RabbitMQ/RabbitMqConsumer.cs

@@ -21,15 +21,16 @@ public class RabbitMqConsumer : BackgroundService
     }
     protected override async Task ExecuteAsync(CancellationToken stoppingToken)
     {
-        var channel = _connection.Channel;
-        if (channel == null)
-            throw new InvalidOperationException("RabbitMQ channel is null");
-
         if (!await _connection.TryConnectAsync())
         {
             _logger.LogError($"RabbitMQ连接失败，请检查配置文件。");
             return;
         }
+
+        var channel = _connection.Channel;
+        if (channel == null)
+            throw new InvalidOperationException("RabbitMQ channel is null");
+
         await channel.QueueDeclareAsync(queue: _handler.QueueName, durable: true, exclusive: false, autoDelete: false, arguments: null);
         await channel.BasicQosAsync(prefetchSize: 0, prefetchCount: 1, global: false);
         var consumer = new AsyncEventingBasicConsumer(channel);