Convert JSON String to Object in C#

Here you will learn how to parse JSON string to class object in C#.

JSON is known as Javascript Object Notation used for storing and transferring data. In the C# application, you often need to convert JSON string data to class objects.

For example, assume that you have the following JSON string:

 "{\"DeptId\": 101, \"DepartmentName\": \"IT\"}"; 

Now, to convert the above string to a class object, the name of the data properties in the string must match with the name of the class properties. To convert the above JSON string, the class should be as below:

public class Department{
    public int DeptId { get; set; }
    public string DepartmentName { get; set; }
}

Notice that the above properties of the above class match with the properties of a JSON string. Therefore, any change in the name would result in an exception.

The .NET Core 3.0 and later versions include the built-in class JsonSerializer in the System.Text.Json namespace that provides functionality for serializing and deserializing from JSON.

The .NET 4.x framework does not provide any built-in JsonSerializer class that converts objects to JSON. You have to install the NuGet package Microsoft.Extensions.Configuration.Json in your project to include the System.Text.Json.JsonSerializer to your project which can be used to convert objects to JSON and vice-versa.

Deserialization is the process of parsing a string into an object of a specific type. The JsonSerializer.Deserialize() method converts a JSON string into an object of the type specified by a generic type parameter.

Syntax:

public static TValue? Deserialize<TValue> (string json, 
                        JsonSerializerOptions? options = default);

The following example shows how to parse a JSON string using the JsonSerializer.Deserialize() method:

string jsonData = "{\"DeptId\": 101, \"DepartmentName\": \"IT\"}";

Department deptObj = JsonSerializer.Deserialize<Department>(jsonData);

Console.WriteLine("Department Id: {0}", deptObj.DeptId);
Console.WriteLine("Department Name: {0}", deptObj.DepartmentName);

Convert JSON Array String to List

Many times the JSON string contains an array to store multiple data. This can be converted to an array or list of objects in C#. The following example shows how to parse JSON array to C# list collection.

string jsonArray = "[{\"DeptId\": 101,\"DepartmentName\":\"IT\" }, {\"DeptId\": 102,\"DepartmentName\":\"Accounts\" }]";

var deptList = JsonSerializer.Deserialize<IList<Department>>(jsonArray);

foreach(var dept in deptList)
{
    Console.WriteLine("Department Id is: {0}", dept.DeptId);
    Console.WriteLine("Department Name is: {0}", dept.DepartmentName);
}

Convert JSON String to Object in AJAX Application

Use the JavaScriptSerializer class to provide serialization and deserialization functionality for AJAX-enabled ASP.NET web applications. The JavaScriptSerializer.Deserialize() method converts the specified JSON string to the type of the specified generic parameter object.

The following example shows how to parse JSON string using JavaScriptSerializer.Deserialize() method.

using System;
using System.Collections.Generic;
using System.Web.UI;
using System.Web.Script.Serialization;

namespace MyWebApplication
{
    public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            string jsonDept = @"{'DeptId': '101', 'DepartmentName': 'IT'}";
            var serializer = new JavaScriptSerializer();
            Department deptObj = new serializer.Deserialize<Department>(jsonDept);
        }
    }

    public class Department
    {
        public int DeptId { get; set; }
        public string DepartmentName { get; set; }
    }
}

Learn more about System.Web.Script.Serialization.JavaScriptSerializer.

Thus, convert the JSON string to class object in C# using the JsonSerializer.Deserialize() method.

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