在 Visual Basic 中反序列化 JSON [英] Deserializing JSON in Visual basic

问题描述

基本上，我正在尝试使用 4chan JSON API 解析来自 4chan 线程的评论.https://github.com/4chan/4chan-API

Basically, I'm trying to parse the comments from a 4chan thread using the 4chan JSON API. https://github.com/4chan/4chan-API

基本上，有一个叫做 input 的富文本框，另一个叫做 post_text_box.我试图做的是让来自 4chan 线程的 JSON 输入到输入文本框中，并从该 JSON 中提取注释并显示在输出文本框中

basically, there is one rich text box called input, and another called post_text_box. What im trying to do is make it so that JSON from a 4chan thread entered in the input text box, and comments are extracted from that JSON and displayed in the output text box

但是，每当我尝试单击开始"按钮时，什么都没有发生.

however, whenever I try clicking the Go button nothing happens.

这是我目前的代码

Imports System.Web.Script.Serialization
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq

Public Class Form1
    Private Sub start_button_Click(sender As Object, e As EventArgs) Handles start_button.Click
        Dim j As Object = New JavaScriptSerializer().Deserialize(Of Post)(input.Text)

        post_text_box.Text = j.com
    End Sub
End Class

Public Class Rootobject
    Public Property posts() As Post
End Class

Public Class Post
    Public Property no As Integer
    Public Property now As String
    Public Property name As String
    Public Property com As String
    Public Property filename As String
    Public Property ext As String
    Public Property w As Integer
    Public Property h As Integer
    Public Property tn_w As Integer
    Public Property tn_h As Integer
    Public Property tim As Long
    Public Property time As Integer
    Public Property md5 As String
    Public Property fsize As Integer
    Public Property resto As Integer
    Public Property bumplimit As Integer
    Public Property imagelimit As Integer
    Public Property replies As Integer
    Public Property images As Integer
End Class

推荐答案

由于您要导入 Newtonsoft.Json，因此您只需使用 JsonConvert.DeserializeObject(String) 方法:

Since you're importing Newtonsoft.Json, you can just use the JsonConvert.DeserializeObject<T>(String) method:

Dim exampleJson As String = "{ 'no':'123', 'name':'Some Name', 'com':'This is a comment'}"
Dim post As Post = JsonConvert.DeserializeObject(Of Post)(exampleJson)
Dim com As String = post.com
post_text_box.Text = com

或者，如果您不想为 Post 创建一个类，您可以使用 JsonConvert.DeserializeAnonymousType(String, T):

Alternatively, if you don't want to create a class for Post, you can use JsonConvert.DeserializeAnonymousType<T>(String, T):

Dim exampleJson As String = "{ 'no':'123', 'name':'Some Name', 'com':'This is a comment'}"
Dim tempPost = New With {Key .com = ""}
Dim post = JsonConvert.DeserializeAnonymousType(exampleJson, tempPost)
Dim com As String = post.com
post_text_box.Text = com

编辑:看起来您正在从 API 获取一个数组:

EDIT: It looks like you're getting an array back from the API:

{
    "posts" : [{
            "no" : 38161812,
            "now" : "11/19/13(Tue)15:18",
            "name" : "Anonymous",
            "com" : ‌​ "testing thread for JSON stuff",
            "filename" : "a4c",
            "ext" : ".png",
            "w" : 386,
            "h" : 378,
            "tn_w" : 250,
            "tn_h" : 244,
            "tim" ‌​ : 1384892303386,
            "time" : 1384892303,
            "md5" : "tig/aNmBqB+zOZY5upx1Fw==",
            "fsize" : 6234,
            "‌​resto" : 0,
            "bumplimit" : 0,
            "imagelimit" : 0,
            "replies" : 0,
            "images" : 0
        }
    ]
}

在这种情况下，您需要将正在反序列化的类型更改为 Post():

In that case, you will need to change the type that is being deserialized to Post():

首先，添加另一个小包装类:

First, add another small wrapper class:

Public Class PostWrapper
    Public posts() As Post
End Class

然后调整你的反序列化代码:

Then adjust your deserialization code:

Dim json As String = input_box.Text
Dim postWrapper = JsonConvert.DeserializeObject(Of PostWrapper)(json) ' Deserialize array of Post objects
Dim posts = postWrapper.posts

If posts.Length = 1 Then ' or whatever condition you prefer
    post_text_box.Text = posts(0).com
End If

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