Import specific properties from JSON

Introduction

Learn how to read a json string with known properties and remove unwanted properties, followed by deserializing to a strongly typed class.

From incoming to desired data type

For this demonstration, the following data is incoming data with an extra property, Age, and two properties, Name and Last, which need to be FirstName and LastName.

[
  {
    "Id": 1,
    "Name": "Mary",
    "Last": "Jones",
    "Age": 22
  },
  {
    "Id": 2,
    "Name": "John",
    "Last": "Burger",
    "Age": 44
  },
  {
    "Id": 3,
    "Name": "Anne",
    "Last": "Adams",
    "Age": 33
  },
  {
    "Id": 4,
    "Name": "Paul",
    "Last": "Smith",
    "Age": 29
  },
  {
    "Id": 5,
    "Name": "Lucy",
    "Last": "Brown",
    "Age": 25
  }
]

The class to import data into.

public class Person
{
    public int Id { get; set; }
    [JsonPropertyName("Name")]
    public string FirstName { get; set; }
    [JsonPropertyName("Last")]
    public string LastName { get; set; }
}

Aliasing properties

JsonPropertyName is used to alias from property names in json to what is in the class.

Removing unwanted properties

This is a simple process, read in a json file with the correct format followed iterating the array and for each item remove one or more properties. Here only one property is being removed.

var jsonArray = JsonNode.Parse(File.ReadAllText("peopleIncoming.json"))!.AsArray();

foreach (var item in jsonArray)
{
    JsonObject obj = item!.AsObject();
    obj.Remove("Age");
}

Next, place the modified json into a variable and write the json to a file.

var updatedJson = jsonArray.ToJsonString(Indented);

DisplayUpdatedJsonPanel(updatedJson);

Console.WriteLine();

File.WriteAllText("People.json", updatedJson);

Indented definition

public static JsonSerializerOptions Indented => new() { WriteIndented = true };

Deserializing to the Person class

var people = JsonSerializer.Deserialize<Person[]>(updatedJson);

The following screenshot is from a sample project that is included.

Summary

With the provided instructions, it is easy to import json data into a desired format.

Karen Payne @karenpayneoregon