我有一个基本的Neo4j DB,我正在想办法把数据从它变成.Net Core下的C#。我在4.03的DB上使用bolt连接。Windows 10。我可能还没有掌握图形数据库,但我正试图建立一个包含Position的Person对象,其中包含Skill和Ranks。
这段代码返回6个Person的实例(我有6个实例,但这是个小问题,我有点担心
var cv = client.Cypher.Match("(person:Person {UserNumber:5})-[:HAS]->(position:Position)<-[:WITHIN]-(skill:Skill)<-[:ON]-(rank:Rank)")
.Return(person => person.As<Person>());
人物类
public class Person
{
public Person() {
RankingProfile = new List<decimal>();
EmailConfirmed = false;
}
…lots of variables (dates, string decimals, boolean)
public List<decimal> RankingProfile { get; set; }
}
改变结果格式,尝试构建复合对象,但只从Person开始(已添加.Results以获得异常),我得到一个Type初始化器不可调用。异常。
var cv = client.Cypher.Match("(person:Person {UserNumber:5})-[:HAS]->(position:Position)<-[:WITHIN]-(skill:Skill)<-[:ON]-(rank:Rank)")
.Return(person => new {
Person = person.As<Person>()
}).Results;
给了我下面的异常。挖掘异常意味着我需要一个无参数的构造函数,我添加了。 现在有点迷茫了。
System.Reflection.TargetInvocationException
HResult=0x80131604
Message=Exception has been thrown by the target of an invocation.
Source=Neo4jClient
StackTrace:
at Neo4jClient.BoltGraphClient.Neo4jClient.IRawGraphClient.ExecuteGetCypherResults[TResult](CypherQuery query)
at Neo4jClient.Cypher.CypherFluentQuery`1.get_Results()
at SonOFMatrix.Controllers.CVController.Get() in C:\Users\Controllers\CVController.cs:line 29
at Microsoft.Extensions.Internal.ObjectMethodExecutor.Execute(Object target, Object[] parameters)
at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.SyncObjectResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeActionMethodAsync()
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.InvokeNextActionFilterAsync()
This exception was originally thrown at this call stack:
[External Code]
Inner Exception 1:
MemberAccessException: Type initializer was not callable.
StackTrace "
at System.Reflection.RuntimeConstructorInfo.ThrowNoInvokeException()
at System.Reflection.RuntimeConstructorInfo.Invoke(BindingFlags invokeAttr, Binder binder, Object[] parameters, CultureInfo culture)
at System.Reflection.ConstructorInfo.Invoke(Object[] parameters)
at Neo4jClient.StatementResultHelper.ConstructNew[T]()
at Neo4jClient.StatementResultHelper.Parse[T](IRecord record, String identifier, IGraphClient graphClient)" string
这是因为我使用的日期时间而导致的失败。数据库中的日期时间的格式如下(包括时区)"1939-06-23T01:00:00+01:00"。把结尾的 +01:00 删掉,它就能在 Person 对象上工作了,其日期时间为
public DateTime BirthDate { get; set; }
在对象类中使用Neo4j.Driver.V1允许我指定一个ZonedDateTime。这与包含时区的原始日期格式是一致的。
public ZonedDateTime BirthDate { get; set; }
非常感谢克里斯,如果没有你的评论,我将会在这里跌跌撞撞地走很久。