Merge pull request #18062 from abpframework/auto-merge/rel-7-4/2261

Merge branch dev with rel-7.4

framework/src/Volo.Abp.Cli.Core/Volo/Abp/Cli/ServiceProxying/CSharp/CSharpServiceProxyGenerator.cs

@@ -538,8 +538,11 @@ public class CSharpServiceProxyGenerator : ServiceProxyGeneratorBase<CSharpServi
             usingNamespaceList?.AddIfNotContains($"using {GetTypeNamespace(typeName)};");
             return NormalizeTypeName(typeName.Split(".").Last());
         }
-        
-        AddGenericTypeUsingNamespace(typeName, usingNamespaceList);
+
+        if(usingNamespaceList != null)
+        {
+            AddGenericTypeUsingNamespace(typeName, usingNamespaceList);
+        }
         
         var type = new StringBuilder();
         var s1 = typeName.Split("<");