src/Hotline.Application/Mappers/KnowledgeMapperConfigs.cs

@@ -66,6 +66,9 @@ public class KnowledgeMapperConfigs : IRegister
             .AfterMapping((s, d) => d.Id = s.KnowledgeTypeId)
             ;
 
+        config.ForType<KnowledgeApprove, KnowledgeApproveDto>()
+            .IgnoreIf((s, d) => s.Approver == null, d => d.Approver);
+
         #endregion
     }
 }