Question

我正在使用Neo4jClient找到的示例尝试Neo4j图表数据库的here。

以下相当简单的代码：

var client = new GraphClient(new Uri("http://localhost:7474/db/data"));
client.Connect();

var myNodeReference = client.Create(new MyNode { Foo = "bar" });
var myNode = client.Get<MyNode>(myNodeReference);

在最后一行（.Get）上抛出以下错误：

An item with the same key has already been added.

（即使Get是第一个也是唯一的方法，也会抛出相同的错误，并且我通过使用之前创建的一些现有密钥来获取节点。

在查看堆栈跟踪后，我发现它与Neo4jClient相关，而不是与Neo4j db相关，因为它似乎是在添加到Dictionary时抛出的错误：

 at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector)
   at Neo4jClient.Deserializer.CommonDeserializerMethods.GetPropertiesForType(Type objType) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CommonDeserializerMethods.cs:line 344
   at Neo4jClient.Deserializer.CommonDeserializerMethods.Map(Object targetObject, JToken parentJsonToken, CultureInfo culture, IEnumerable`1 typeMappings, Int32 nestingLevel) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CommonDeserializerMethods.cs:line 228
   at Neo4jClient.Deserializer.CommonDeserializerMethods.CreateAndMap(Type type, JToken element, CultureInfo culture, IEnumerable`1 typeMappings, Int32 nestingLevel) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CommonDeserializerMethods.cs:line 210
   at Neo4jClient.Deserializer.CommonDeserializerMethods.SetPropertyValue(Object targetObject, PropertyInfo propertyInfo, JToken value, CultureInfo culture, IEnumerable`1 typeMappings, Int32 nestingLevel) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CommonDeserializerMethods.cs:line 132
   at Neo4jClient.Deserializer.CommonDeserializerMethods.Map(Object targetObject, JToken parentJsonToken, CultureInfo culture, IEnumerable`1 typeMappings, Int32 nestingLevel) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CommonDeserializerMethods.cs:line 234
   at Neo4jClient.Deserializer.CustomJsonDeserializer.Deserialize[T](RestResponse response) in c:\TeamCity\buildAgent\work\460e89b30f53245b\Neo4jClient\Deserializer\CustomJsonDeserializer.cs:line 59
   at RestSharp.RestClient.Deserialize[T](IRestRequest request, RestResponse raw)

如果相关，这些是NuGet的包版本：
    <package id="Neo4jClient" version="1.0.0.397" targetFramework="net40-Client" />
    <package id="Newtonsoft.Json" version="4.0.8" targetFramework="net40-Client" />
    <package id="RestSharp" version="102.7" targetFramework="net40-Client" />

我在这里做错了什么？

修改 MyNode课程：

[JsonObject]
public class MyNode
{
    [JsonProperty("Bar")]
    public string Foo { get; set; }

    [JsonIgnore]
    public string Bar { get; set; }
}

Answer 1

除非你真的需要这样做，否则我会取消[JsonProperty("Bar")]位，因为这是造成麻烦的原因。反序列化器无法区分实际属性“Bar”和JsonProperty“Bar”

如果你取消它，你的代码将正常工作。

如果想要使用Json的东西，你可以创建另一个Node对象：

public class OtherNode { public string Bar { get;set;} }

并反序列化：

var nodeReference = client.Create(new MyNode { Foo = "blah" });
var retrieved = client.Get<OtherNode>(nodereference);

这将有效。

Neo4jClient - 如何获取节点？

1 个答案: