MSDN Documentation

Windows Programming: Data

Working with JSON in Windows Applications

JavaScript Object Notation (JSON) is a lightweight data-interchange format that is easy for humans to read and write and easy for machines to parse and generate. It is built upon two structures:

  • A collection of name/value pairs (in various languages, it is realized as a dictionary, record, struct, object, hash table, keyed list, or associative array).
  • An ordered list of values (in most languages, this is realized as an array, vector, list, or sequence).

This document provides guidance on how to effectively use JSON within your Windows applications, covering parsing, generation, and common patterns.

Key Advantages of JSON

  • Readability: Simple, human-readable format.
  • Lightweight: Less verbose than XML, leading to smaller payloads.
  • Ubiquity: Widely used in web APIs and modern application architectures.
  • Interoperability: Easily exchanged between different programming languages and platforms.

Parsing JSON Data

Windows applications can leverage several built-in and third-party libraries to parse JSON strings into native data structures.

Using Windows Runtime (WinRT) JSON APIs

For Universal Windows Platform (UWP) and modern Windows applications, the Windows Runtime provides powerful JSON parsing capabilities.


using Windows.Data.Json;

public void ParseJsonString(string jsonString)
{
    try
    {
        JsonValue jsonValue = JsonValue.Parse(jsonString);

        if (jsonValue.ValueType == JsonValueType.Object)
        {
            JsonObject jsonObject = jsonValue.GetObject();
            string name = jsonObject.GetNamedString("name");
            int age = (int)jsonObject.GetNamedNumber("age");
            JsonArray hobbies = jsonObject.GetNamedArray("hobbies");

            // Process the parsed data
            System.Diagnostics.Debug.WriteLine($"Name: {name}, Age: {age}");
            foreach (var hobby in hobbies)
            {
                System.Diagnostics.Debug.WriteLine($"- {hobby.GetString()}");
            }
        }
    }
    catch (System.Exception ex)
    {
        System.Diagnostics.Debug.WriteLine($"Error parsing JSON: {ex.Message}");
    }
}

Using Newtonsoft.Json (Json.NET)

For .NET Framework and .NET Core applications, Newtonsoft.Json is a popular and robust third-party library for JSON manipulation.


using Newtonsoft.Json;

public class Person
{
    public string Name { get; set; }
    public int Age { get; set; }
    public string[] Hobbies { get; set; }
}

public void ParseJsonWithNewtonsoft(string jsonString)
{
    try
    {
        Person person = JsonConvert.DeserializeObject<Person>(jsonString);

        // Process the deserialized object
        System.Diagnostics.Debug.WriteLine($"Name: {person.Name}, Age: {person.Age}");
        foreach (var hobby in person.Hobbies)
        {
            System.Diagnostics.Debug.WriteLine($"- {hobby}");
        }
    }
    catch (JsonException ex)
    {
        System.Diagnostics.Debug.WriteLine($"Error deserializing JSON: {ex.Message}");
    }
}

Generating JSON Data

Creating JSON strings from native data structures is equally straightforward.

Using Windows Runtime (WinRT) JSON APIs


using Windows.Data.Json;

public string GenerateJsonString()
{
    JsonObject jsonObject = new JsonObject();
    jsonObject["name"] = JsonValue.CreateStringValue("Alice");
    jsonObject["age"] = JsonValue.CreateNumberValue(30);

    JsonArray hobbiesArray = new JsonArray();
    hobbiesArray.Add(JsonValue.CreateStringValue("Reading"));
    hobbiesArray.Add(JsonValue.CreateStringValue("Hiking"));
    jsonObject["hobbies"] = hobbiesArray;

    return jsonObject.Stringify();
}

Using Newtonsoft.Json (Json.NET)


using Newtonsoft.Json;

public string GenerateJsonWithNewtonsoft()
{
    var person = new Person
    {
        Name = "Bob",
        Age = 25,
        Hobbies = new string[] { "Gaming", "Coding" }
    };

    return JsonConvert.SerializeObject(person, Formatting.Indented);
}

Common JSON Structures and Patterns

Understanding typical JSON structures can help you map them to your application's data models more efficiently.

Arrays of Objects

This is a very common pattern for representing collections of items.


[
  {
    "id": 101,
    "productName": "Laptop",
    "price": 1200.00
  },
  {
    "id": 102,
    "productName": "Keyboard",
    "price": 75.50
  }
]

Nested Objects

Used to represent hierarchical data relationships.


{
  "orderId": "ORD789",
  "customer": {
    "firstName": "Jane",
    "lastName": "Doe",
    "address": {
      "street": "123 Main St",
      "city": "Anytown",
      "zipCode": "12345"
    }
  },
  "totalAmount": 150.75
}

Best Practices

  • Use consistent naming conventions for JSON keys (e.g., camelCase or snake_case).
  • Validate incoming JSON data to prevent errors and security vulnerabilities.
  • Consider using dedicated JSON schema validation for complex data structures.
  • For large datasets, consider streaming JSON parsing if available in your chosen library.

Further Reading