UiPath - issue - "Newtonsoft.Json.JsonSerializationException: Cannot create and populate list type System"

【问题描述】

用 UiPath (2019.3.0 Community Edition) 编写了一个非常简单的Tool，但是运行的时候出现了异常，下图是 Designer panel 的 workflow 和 异常截图

 

以下是详细的报错信息：

19.3.0+Branch.master.Sha.5fdb43627d7d3c011018bb545ddf9470210d44a9


Cannot create and populate list type System.Collections.Generic.IReadOnlyCollection`1[System.String]. Path 'ReferencedAssemblies.$values', line 1, position 373.


System.ServiceModel.FaultException`1[System.ServiceModel.ExceptionDetail]: Cannot create and populate list type System.Collections.Generic.IReadOnlyCollection`1[System.String]. Path 'ReferencedAssemblies.$values', line 1, position 373. (Fault Detail is equal to An ExceptionDetail, likely created by IncludeExceptionDetailInFaults=true, whose value is:
Newtonsoft.Json.JsonSerializationException: Cannot create and populate list type System.Collections.Generic.IReadOnlyCollection`1[System.String]. Path 'ReferencedAssemblies.$values', line 1, position 373.
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateNewList(JsonReader reader, JsonArrayContract contract, Boolean& createdFromNonDefaultCreator)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateList(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, Object existingValue, String id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.ReadMetadataProperties(JsonReader reader, Type& objectType, JsonContract& contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue, Object& newValue, String& id)
   at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObje...).

 

问题关键点：

Newtonsoft.Json.JsonSerializationException: Cannot create and populate list type System

 

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【解决方法】

原因：

Newtonsoft.Json 不兼容版本被加载到了 Global Assembly Cache（GAC）里边。

 

操作：

第一步，在C盘中搜索 Newtonsoft.Json.dll 

 

第二步，右键打开该文件所在文件夹 -  Open Location

第三步，往上两级，将整个 Newtonsoft.Json 文件夹 剪切到另外别的地方保存

 

第四步，重新安装 UiPath，再次运行就没有报错了

 

 

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【参考】

https://documentation.red-gate.com/clone2/troubleshooting/common-issues/newtonsoft-json-jsonserializationexception-cannot-create-and-populate-list-type