C#：无法将列表中存储的值写入控制台

Question

I have the following function that allows me to make REST request via this function:

static Observation GetData(string baseUrl, string provider, string key, string sensor)
        {
            var client = new RestClient(String.Format("{0}/data/{1}/{2}", baseUrl, provider, sensor));
            client.Timeout = -1;
            var request = new RestRequest(Method.GET);
            request.AddHeader("IDENTITY_KEY", key);
            IRestResponse response = client.Execute(request);
            Console.WriteLine(response.Content);
            
            var observationsModel = JsonSerializer.Deserialize<SentiloResponse>(response.Content, options);
            Console.WriteLine("This is observationsModel:");
            Console.WriteLine(observationsModel);
            Console.WriteLine("This is the outcome of GetData:");
            Console.WriteLine(observationsModel.Observations.FirstOrDefault());
            return observationsModel.Observations.FirstOrDefault();
        }

The outcome from it is the following (see screenshot):

Now, from this point

In the next section I call GetData, I would like to select Value and Timestamp Variables to do other tasks, but I'm unable to (my attempts are in lines where myTest and myTest_2 are being declared):

static void Main(string[] args)
        {
            configuration = JsonSerializer.Deserialize<SentiloConfig>(File.ReadAllText("configuration.json"), options);
            Console.WriteLine("Configuration Loaded");
            
            foreach(var componentMapping in configuration.ComponentMappings)
            {
                var inputComponent = componentMapping.InputComponent;
                Console.WriteLine("Getting data");
                var sensorsContent = inputComponent.Sensors.AsParallel().Select(s =>
                    new SensorContent{
                        Sensor = GetSensorString(s.SensorName),
                        Observations = new List<Observation>() {
                                
                            GetData(
                                    inputComponent.ServerUrl,
                                    inputComponent.Provider,
                                    inputComponent.Token,
                                    GetSensorString(s.SensorName)
                                    )
                                
                        }
                    }
                ).Where(s => s.Observations.First() != null).ToList();
                var myTest = sensorsContent.Select(s => s.Observations.First().Value).ToList();
                var myTest_2 = sensorsContent.Select(s => s.Observations.First().Value.ToList());
                Console.WriteLine(myTest.ToString());
                Console.WriteLine(myTest_2);
                Console.WriteLine("data retrieved");
                if (!sensorsContent.Any())
                {
                    Console.WriteLine("No sensor data for component {0} with sensors: {1}, check configuration", inputComponent.ComponentName, string.Join(",", inputComponent.Sensors.Select(s => s.SensorName)));
                    continue;
                }
                var sensorRequest = new SentiloPutRequest { Sensors = sensorsContent };
                    
            }
            System.Threading.Thread.Sleep(configuration.SendTime*1000);
            
        }

But the outcome of myTest and myTest_2 are the following:

System.Collections.Generic.List 1[System.String] System.Linq.Enumerable+SelectListIterator 2[SentiloSpoofer.SensorContent,System.Collections.Generic.List`1[System.Char]]

I'm thinking perhaps is best to call GetData outside of the Lambda and bypass these issues, but if I wanted to retrieve this data, what could be a good way to do so?

Answer 1

It's just the way you are writing to the console. Use string.Join or a foreach .

Essentially, you are trying to magic the values out of a list. Technically List<T> doesn't have an override of ToString() that knows how you want to format it. It's up to you. So it just returns the type name (which is what you are seeing).

Try instead:

foreach(var value in myTest)
  Console.WriteLine(value);

// or
Console.WriteLine(string.Join(",",myTest));

Answer 2

You are trying to access a List as a String. The values are there if you wanna show it in your console, just use an aggregate in your List.

Example:

var myTestString = myTest.Select(i => i).Aggregate((i, j) => i + "," + j);
Console.WriteLine(myTestString)

// Or

myTest.ForEach(x => Console.WriteLine(x));