Serializing a list to JSON Serializing a list to JSON json json

Serializing a list to JSON

If using .Net Core 3.0 or later;

Default to using the built in System.Text.Json parser implementation.


using System.Text.Json;var json = JsonSerializer.Serialize(aList);

alternatively, other, less mainstream options are available like Utf8Json parser and Jil: These may offer superior performance, if you really need it but, you will need to install their respective packages.

If stuck using .Net Core 2.2 or earlier;

Default to using Newtonsoft JSON.Net as your first choice JSON Parser.


using Newtonsoft.Json;var json = JsonConvert.SerializeObject(aList);

you may need to install the package first.

PM> Install-Package Newtonsoft.Json

For more details see and upvote the answer that is the source of this information.

For reference only, this was the original answer, many years ago;

// you need to reference System.Web.Extensionsusing System.Web.Script.Serialization;var jsonSerialiser = new JavaScriptSerializer();var json = jsonSerialiser.Serialize(aList);

You can also use Json.NET. Just download it at, extract the compressed file and add it as a reference.

Then just serialize the list (or whatever object you want) with the following:

using Newtonsoft.Json;string json = JsonConvert.SerializeObject(listTop10);

Update: you can also add it to your project via the NuGet Package Manager (Tools --> NuGet Package Manager --> Package Manager Console):

PM> Install-Package Newtonsoft.Json

Documentation: Serializing Collections

There are two common ways of doing that with built-in JSON serializers:

  1. JavaScriptSerializer

    var serializer = new JavaScriptSerializer();return serializer.Serialize(TheList);
  2. DataContractJsonSerializer

    var serializer = new DataContractJsonSerializer(TheList.GetType());using (var stream = new MemoryStream()){    serializer.WriteObject(stream, TheList);    using (var sr = new StreamReader(stream))    {        return sr.ReadToEnd();    }}

    Note, that this option requires definition of a data contract for your class:

    [DataContract]public class MyObjectInJson{   [DataMember]   public long ObjectID {get;set;}   [DataMember]   public string ObjectInJson {get;set;}}