HttpClient 上的串行化擴充方法

將 JSON 資料從網路進行序列化和反序列化是一項常見的操作。 HttpClient 和 HttpContent 上的擴充方法 可讓您在單行程式代碼中執行這些作業。 這些擴充方法會針對 JsonSerializerOptions 使用Web 預設值。

下列範例說明如何使用 HttpClientJsonExtensions.GetFromJsonAsync 和 HttpClientJsonExtensions.PostAsJsonAsync：

using System.Net.Http.Json;

namespace HttpClientExtensionMethods
{
    public class User
    {
        public int Id { get; set; }
        public string? Name { get; set; }
        public string? Username { get; set; }
        public string? Email { get; set; }
    }

    public class Program
    {
        public static async Task Main()
        {
            using HttpClient client = new()
            {
                BaseAddress = new Uri("https://jsonplaceholder.typicode.com")
            };

            // Get the user information.
            User? user = await client.GetFromJsonAsync<User>("users/1");
            Console.WriteLine($"Id: {user?.Id}");
            Console.WriteLine($"Name: {user?.Name}");
            Console.WriteLine($"Username: {user?.Username}");
            Console.WriteLine($"Email: {user?.Email}");

            // Post a new user.
            HttpResponseMessage response = await client.PostAsJsonAsync("users", user);
            Console.WriteLine(
                $"{(response.IsSuccessStatusCode ? "Success" : "Error")} - {response.StatusCode}");
        }
    }
}

// Produces output like the following example but with different names:
//
//Id: 1
//Name: Tyler King
//Username: Tyler
//Email: Tyler@contoso.com
//Success - Created

Imports System.Net.Http
Imports System.Net.Http.Json

Namespace HttpClientExtensionMethods

    Public Class User
        Public Property Id As Integer
        Public Property Name As String
        Public Property Username As String
        Public Property Email As String
    End Class

    Public Class Program

        Public Shared Async Function Main() As Task
            Using client As New HttpClient With {
                .BaseAddress = New Uri("https://jsonplaceholder.typicode.com")
                }

                ' Get the user information.
                Dim user1 As User = Await client.GetFromJsonAsync(Of User)("users/1")
                Console.WriteLine($"Id: {user1.Id}")
                Console.WriteLine($"Name: {user1.Name}")
                Console.WriteLine($"Username: {user1.Username}")
                Console.WriteLine($"Email: {user1.Email}")

                ' Post a new user.
                Dim response As HttpResponseMessage = Await client.PostAsJsonAsync("users", user1)
                Console.WriteLine(
                $"{(If(response.IsSuccessStatusCode, "Success", "Error"))} - {response.StatusCode}")
            End Using
        End Function

    End Class

End Namespace

' Produces output like the following example but with different names:
'
'Id: 1
'Name: Tyler King
'Username: Tyler
'Email: Tyler@contoso.com
'Success - Created