在 Visual Basic 中反序列化 JSON
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Deserializing JSON in Visual basic
提问by user3010090
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，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, 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
基本上，有一个称为 input 的富文本框，另一个称为 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
however, whenever I try clicking the Go button nothing happens.
但是，每当我尝试单击 Go 按钮时，什么也没有发生。
Here is my code so far
到目前为止，这是我的代码
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
回答by valverij
Since you're importing Newtonsoft.Json, you can just use the JsonConvert.DeserializeObject<T>(String)method:
由于您正在导入Newtonsoft.Json，您可以使用以下JsonConvert.DeserializeObject<T>(String)方法：
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
Alternatively, if you don't want to create a class for Post, you can use JsonConvert.DeserializeAnonymousType<T>(String, T):
或者，如果您不想为 创build一个类Post，您可以使用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
EDIT: It looks like you're getting an array back from the API:
编辑：看起来您正在从 API 获取一个数组：
{
"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
}
]
}
In that case, you will need to change the type that is being deserialized to Post():
在这种情况下，您需要将正在反序列化的类型更改为Post()：
First, add another small wrapper class:
首先，添加另一个小包装类：
Public Class PostWrapper
Public posts() As Post
End Class
Then adjust your deserialization code:
然后调整你的反序列化代码：
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
回答by Karl Anderson
Instead of needing to define a class, you can deserialize the JSON into an Object, like this:
无需定义类，您可以将 JSON 反序列化为Object，如下所示：
Dim json As String = "{""items"":[{""Name"":""John"",""Age"":""20"",""Gender"":""Male""},{""Name"":""Tom"",""Age"":""25"",""Gender"":""Male""},{""Name"":""Sally"",""Age"":""30"",""Gender"":""Female""}]}"
Dim jss = New JavaScriptSerializer()
Dim data = jss.Deserialize(Of Object)(json)
Now, as an example, you could loop through the deserialized JSON and build an HTML table, like this:
现在，作为示例，您可以遍历反序列化的 JSON 并构建一个 HTML 表，如下所示：
Dim sb As New StringBuilder()
sb.Append("<table>" & vbLf & "<thead>" & vbLf & "<tr>" & vbLf)
' Build the header based on the keys of the first data item.
For Each key As String In data("items")(0).Keys
sb.AppendFormat("<th>{0}</th>" & vbLf, key)
Next
sb.Append("</tr>" & vbLf & "</thead>" & vbLf & "<tbody>" & vbLf)
For Each item As Dictionary(Of String, Object) In data("items")
sb.Append("<tr>" & vbLf)
For Each val As String In item.Values
sb.AppendFormat(" <td>{0}</td>" & vbLf, val)
Next
Next
sb.Append("</tr>" & vbLf & "</tbody>" & vbLf & "</table>")
Dim myTable As String = sb.ToString()
Disclaimer: I work with C# on a daily basis and this is a C# example using dynamicthat was converted to VB.NET, please forgive me if there are any syntax errors with this.
免责声明：我每天都在使用 C#，这是一个 C# 示例，使用dynamic它转换为 VB.NET，如果有任何语法错误，请原谅我。
回答by prog2011
Also, if you have complex json string. If there is subclasses, arrays, etc. in the json string, you can use this way at below. I tried it and it worked for me. I hope it will useful for you.
另外，如果您有复杂的 json 字符串。如果json字符串中有子类、数组等，可以在下面使用这种方式。我试过了，它对我有用。我希望它对你有用。
I accessed root->simpleforecast->forecastday[]->date->hight->celsius,fahrenheit values etc. in the json string.
我在 json 字符串中访问了 root->simpleforecast->forecastday[]->date->hight->celsius、fahrenheit 值等。
Dim tempforecast = New With {Key .forecast = New Object}
Dim sFile As String = SimpleTools.RWFile.ReadFile("c:\testjson\test.json")
Dim root = JsonConvert.DeserializeAnonymousType(sFile, tempforecast)
Dim tempsimpleforecast = New With {Key .simpleforecast = New Object}
Dim forecast = jsonConvert.DeserializeAnonymousType(root.forecast.ToString(), tempsimpleforecast)
Dim templstforecastday = New With {Key .forecastday = New Object}
Dim simpleforecast = JsonConvert.DeserializeAnonymousType(forecast.simpleforecast.ToString(), templstforecastday)
Dim lstforecastday = simpleforecast.forecastday
For Each jforecastday In lstforecastday
Dim tempDate = New With {Key .date = New Object, .high = New Object, .low = New Object}
Dim forecastday = JsonConvert.DeserializeAnonymousType(jforecastday.ToString(), tempDate)
Dim tempDateDetail = New With {Key .day = "", .month = "", .year = ""}
Dim fcDateDetail = JsonConvert.DeserializeAnonymousType(forecastday.date.ToString(), tempDateDetail)
Weather_Forcast.ForcastDate = fcDateDetail.day.ToString() + "/" + fcDateDetail.month.ToString() + "/" + fcDateDetail.year.ToString()
Dim temphighDetail = New With {Key .celsius = "", .fahrenheit = ""}
Dim highDetail = JsonConvert.DeserializeAnonymousType(forecastday.high.ToString(), temphighDetail)
Dim templowDetail = New With {Key .celsius = "", .fahrenheit = ""}
Dim lowDetail = JsonConvert.DeserializeAnonymousType(forecastday.low.ToString(), templowDetail)
Weather_Forcast.highCelsius = Decimal.Parse(highDetail.celsius.ToString())
Weather_Forcast.lowCelsius = Decimal.Parse(lowDetail.celsius.ToString())
Weather_Forcast.highFahrenheit = Decimal.Parse(lowDetail.fahrenheit.ToString())
Weather_Forcast.lowFahrenheit = Decimal.Parse(lowDetail.fahrenheit.ToString())
Weather_Forcast09_Result.Add(Weather_Forcast)
Next
回答by Kannadasan K
Note:
笔记：
First you have to install Newtonsoft.Json on nuget console. Then include following code on top of your code.
首先，您必须在 nuget 控制台上安装 Newtonsoft.Json。然后在您的代码之上包含以下代码。
Imports Newtonsoft.Json
Step:1 Create class with get & set properties.
步骤：1 创建具有获取和设置属性的类。
Public Class Student
Public Property rno() As String
Get
Return m_rno
End Get
Set(value As String)
m_rno = value
End Set
End Property
Private m_rno As String
Public Property name() As String
Get
Return m_name
End Get
Set(value As String)
m_name = value
End Set
End Property
Private m_name As String
Public Property stdsec() As String
Get
Return m_StdSec
End Get
Set(value As String)
m_StdSec = value
End Set
End Property
Private m_stdsec As String
End Class
Step: 2 Create string as a json format and conver as a json object model.
步骤：2 将字符串创建为 json 格式并转换为 json 对象模型。
Dim json As String = "{'rno':'09MCA08','name':'Kannadasan Karuppaiah','stdsec':'MCA'}"
Dim stuObj As Student = JsonConvert.DeserializeObject(Of Student)(json)
Step: 3 Just traverses by object.entity name as follows.
步骤：3 只需按object.entity name 遍历如下。
MsgBox(stuObj.rno)
MsgBox(stuObj.name)
MsgBox(stuObj.stdsec)
