Neo4j.Map.Extension

What is Neo4j.Map.Extension?

Neo4j.Map.Extension is a simple tool that was born from an experiment while I was learning how to use Neo4j.Driver to execute queries in Neo4j. After some repetitive query parses, I tried to make it more abstract for me, using some attributes to configure a graph node as a custom C# class.

Where can I get it?

You can install Neo4j.Map.Extension using

Package Manager

PM> Install-Package Neo4j.Map.Extension

Paket CLI

> paket add Neo4j.Map.Extension

.NET CLI

> dotnet add package Neo4j.Map.Extension

How to use it?

There are two attributes that you can use to set up your custom class, Neo4jLabelAttribute to map your classes and Neo4jPropertyAttribute to map your properties. If you have any class which you want its properties values to be bind by Neo4j.Map.Extension, it must inherit from Neo4jNode class.

[Neo4jLabel("Employee")]
class Employee : Neo4jNode
{
    [Neo4jProperty(Name = "name")]
    public string Name { get; set; }

    [Neo4jProperty(Name = "occupation")]
    public Ocuppation Ocuppation { get; set; }

    public override string ToString()
    {
        return $"Person {{Employee: '{UUID}', Name: '{Name}', Occupation: '{Ocuppation}'}}";
    }
}

UUID is a default property inherited from the Neo4jNode class. UUID is a value generated to guarantee that all your nodes have one unique identity value. You can read more about it on neo4j-uuid

Map() - Binding node values to properties

Once you get the return from Neo4j server, you can use the Map extension method to check and bind all the values of you graph node into your custom class.

IDriver driver = GraphDatabase.Driver("bolt://127.0.0.1:7687", AuthTokens.None);
List<Employee> nodes = new List<Employee>();
using (ISession session = driver.Session(AccessMode.Read))
{
    IStatementResultCursor result = await session.RunAsync("MATCH (n:Employee) return n");
    await result.ForEachAsync(r =>
    {
        nodes.Add(r[r.Keys[0]].Map<Employee>());
    });
}