使用POCO类的mongodb graphLookup c#示例

// 定义POCO类
public class Employee
{
    public ObjectId Id { get; set; }
    public string Name { get; set; }
    public ObjectId ManagerId { get; set; }
}

// 创建mongodb客户端
var client = new MongoClient("mongodb://localhost:27017");

// 获取数据库和集合
var database = client.GetDatabase("mydb");
var collection = database.GetCollection<Employee>("employees");

// 构建graphLookup查询
var pipeline = new BsonDocument[]
{
    new BsonDocument("$graphLookup", new BsonDocument
    {
        { "from", "employees" },
        { "startWith", "$ManagerId" },
        { "connectFromField", "ManagerId" },
        { "connectToField", "_id" },
        { "as", "reportingHierarchy" }
    })
};

// 执行查询
var result = collection.Aggregate<Employee>(pipeline).ToList();

// 输出结果
foreach (var employee in result)
{
    Console.WriteLine($"Employee: {employee.Name}");
    foreach (var reportee in employee.reportingHierarchy)
    {
        Console.WriteLine($"- Reportee: {reportee.Name}");
    }
}