如何从 System.Text.Json 中的 JsonNode 读取值

Question

I want to serialize a refresh token and send it to the client.

Then on return, I want to deserialize and read it.

Here's my code.

using System.Text.Json;
using System.Dynamic;
using System;
using System.Text.Encodings.Web;
using System.Text.Unicode;
using System.Text.Json.Nodes;


dynamic token = new ExpandoObject();

token.UserName = "John";
token.Expires = DateTime.Now.AddMinutes(5);
token.CreateDate = DateTime.Now;

var options = new JsonSerializerOptions
                {
                    PropertyNameCaseInsensitive = true,
                    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
                    DictionaryKeyPolicy = JsonNamingPolicy.CamelCase,
                    Encoder = JavaScriptEncoder.Create(UnicodeRanges.All)
                };

var refreshToken = JsonSerializer.Serialize(token,  options);

Console.WriteLine(refreshToken);

var deserializedToken = JsonSerializer.Deserialize<JsonNode>(refreshToken, options);

var userName = "How can I extract username from JsonNode";

I tried to use JsonNode["UserName"].Value , but it does not work.

Answer 1

Since you are using dynamic all subsequent variables are resolved as dynamic too. Just declare one of the types (for example string for serialization result) and use indexer + GetValue :

string refreshToken = JsonSerializer.Serialize(token,  options);

JsonNode? deserializedToken = JsonSerializer.Deserialize<JsonNode>(refreshToken, options);
var userName = deserializedToken["userName"].GetValue<string>();

Answer 2

you can just use Parse

JsonNode deserializedToken = JsonNode.Parse(refreshToken);
string userName = (string) deserializedToken["userName"];