Question 296094 in Json Question posted in
Our archive of expertly curated questions and answers provides insights and solutions to common problems related to this popular data interchange format. From parsing and manipulating JSON data to integrating it with various programming languages and web services, our archive has got you covered. Start exploring today and take your JSON skills to the next level

C# handling multiple elements in a JSON file

I have a JSON file with the following structure:

{
    "name": "ML4 093 Historical",
    "unit": "pounds",
    "data":[
        {
            "date": "1985-12-01",
            "value": "250"
        },
        {
            "date": "1985-11-01",
            "value": "237"
        },
        {
            "date": "1985-10-01",
            "value": "286"
        }
    ]
}

Long story short, I need to get the value that corresponds to a specific date (for example, 250 for 1985-12-01 or 237 for 1985-11-01).

I understand how to get the information for a single element (for example, getting pounds for unit), but I have no clue how to go about doing it in this case.

This is what I have to get the information for a single element:

using System.Text.Json;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace test
{

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void Form1_Load(object sender, EventArgs e)
        {
             Label unitname = label3;

            string QUERY_URL = "JSON URL HERE";
                Uri queryUri = new Uri(QUERY_URL);

            using (System.Net.WebClient client = new System.Net.WebClient())
            {
                  var json_data = client.DownloadString(queryUri);

                  var jsonDocument = JsonDocument.Parse(json_data);

                  var rootElement = jsonDocument.RootElement;

                  var unitElement = rootElement.GetProperty("unit");

                  var unit = unitElement.GetString();

                  unitname.Text = unit;
            }

        }
    }
}

JSON URL HERE is, obviously, replaced with the actual URL in the code – I just can’t share it publicly.

Tags:

2

Answers


  1. 0

    You can create a class representing this JSON object (keeping in mind that Data should be an entirely separate object, inside the parent object), like so:

        public class DataObject
    {
        public string date { get; set; }
        public string value { get; set; }
    }

    public class FormObject
    {
        public string name { get; set; }
        public string unit { get; set; }
        public List<Data> data { get; set; }
    }

    Then to retrieve the value, an example would be:

    var rootElement = (DataObject)jsonDocument.RootElement;  //there are other better ways to do this - you might want to take a look at Automapper library
var unitElement = rootElement.Data[1].Value  //to get the first data value element.
    Login or Signup to reply.
  2. 0

    You can create a model class

    DataModel.cs

    using System.Collections.Generic;

namespace MyFoodBag.Forecast.Presentation.Forecaster.Models
{
    public class DataModel
    {
        public string Name { get; set; }
        public string Unit { get; set; }
        public List<Data> Data { get; set; }
    }

    public class Data
    {
        public string Date { get; set; }
        public string Value { get; set; }
    }
}

    After that just a little modification in you code should work

    using System.Text.Json;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace test
{

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }


        private void Form1_Load(object sender, EventArgs e)
        {
             Label unitname = label3;

            string QUERY_URL = "JSON URL HERE";
            Uri queryUri = new Uri(QUERY_URL);

            using (System.Net.WebClient client = new System.Net.WebClient())
            {
                  var json_data = client.DownloadString(queryUri);
                  // map json to model object
                  var dataModel= JsonConvert.DeserializeObject<DataModel>(json_data);

                  var valueForDate = dataModel.Data.Where(x => x.Date == <whateverdate>).Select(v => v.Value);
            }

        }
    }
}
    Login or Signup to reply.
Please signup or login to give your own answer.

Back To Top
Search