vb.net 在 Visual Basic 中使用 json.net 解析嵌套的 JSON

Parse nested JSON with json.net in Visual Basic

提问by user1829564

I have nested JSON strings that i would like to parse out the appropriate values from much like below. As i am learning by doing I am struggling a little bit, I have the first part working in that I can parse out single JSON strings, and return the appropriate value using code example 1 below, however i am stuck with a JSON string that is problematic in that it is nested, so the same approach won't work

我有嵌套的 JSON 字符串，我想从下面的很像中解析出适当的值。当我边做边学时我有点挣扎，我有第一部分工作，我可以解析单个 JSON 字符串，并使用下面的代码示例 1 返回适当的值，但是我被困在一个 JSON 字符串中问题在于它是嵌套的，所以同样的方法不起作用

{
  "jsonrpc":"2.0",
  "method":"Player.OnPause",
  "params":{
     "data": { "item": { "id":29, "type":"episode" },
               "player": { "playerid":1, "speed":0 }
             },
     "sender":"xbmc"
  }
}

And the code...

还有代码...

    Dim JSON As String
    Dim values As Newtonsoft.Json.Linq.JObject
    JSON = JSON STRING WOULD GO HERE, COMES from TCP IP STREAM
    values = JObject.Parse(JSON)
    Console.WriteLine(values.GetValue("method"))

Using that example i can extract the method key (e.g. Player.OnPause) from the first level JSON string, but how can i extract data from the second, and third level strings, For example in the above string, being able to get to Data level JSON values, and Item level JSON values. Is this possible in a similar way to the above?

使用该示例，我可以从第一级 JSON 字符串中提取方法键（例如 Player.OnPause），但是如何从第二级和第三级字符串中提取数据，例如在上面的字符串中，能够获取数据级别 JSON 值和项目级别 JSON 值。这可能以与上述类似的方式进行吗？

Appreciate any tips you could provide, I am a learn by examples person, but just struggling to apply something to read multiple nested JSON strings, or multiple levels. No doubt it will be an easy thing that i am missing, but id appreciate any help someone could provide.

感谢您提供的任何提示，我是一个通过示例学习的人，但只是努力应用某些东西来读取多个嵌套的 JSON 字符串或多个级别。毫无疑问，我错过了这将是一件容易的事情，但我很感激有人可以提供的任何帮助。

Thanks

谢谢

回答by igrimpe

    Dim jsonstring = IO.File.ReadAllText("json.txt")
    Dim jo = Json.Linq.JObject.Parse(jsonstring)
    Dim playerid = jo("params")("data")("player")("playerid")

Do you mean something like this? "json.txt" simply contains your JSON string.

你的意思是这样的吗？“json.txt”只包含您的 JSON 字符串。

回答by Simon Barnett

After searching here and else where for an polymorhic example of parsing javascrip object notation into a .net dictionary I gave up and wrote my own. Hope someone finds this useful ;)

在here和其他地方搜索将javascrip对象表示法解析为.net字典的多态示例后，我放弃并编写了自己的字典。希望有人觉得这很有用 ;)

Public Class jsonDictionary
    Inherits Dictionary(Of String, Object)

#Region "Public Properties"
    Private _parent As jsonDictionary
    Public ReadOnly Property Parent() As jsonDictionary
        Get
            Return _parent
        End Get
    End Property

#End Region

#Region "Initialisation and Finalisation"

    Public Sub New(ByVal Parent As jsonDictionary, ByVal strJson As String)
        _parent = Parent
        For Each Element As String In SplitJSON(CharTrim(strJson))
            Dim elName As String = CharTrim(Element.Split(":")(0).Trim)
            Select Case Element.Split(":")(1).Trim.Substring(0, 1)
                Case "{"
                    Me.Add(elName, New jsonDictionary(Me, Element.Substring(InStr(Element, ":"))))
                Case "["
                    Dim ElArray As New List(Of jsonDictionary)
                    For Each ArrayElement As String In SplitJSON(CharTrim(Element.Substring(InStr(Element, ":"))))
                        ElArray.Add(New jsonDictionary(Me, ArrayElement))
                    Next
                    Me.Add(elName, ElArray)
                Case Else
                    Me.Add(elName, Element.Split(":")(1).Trim)
            End Select

        Next
    End Sub

#End Region

#Region "Private Methods"

    Public Shared Function CharTrim(ByVal Str As String) As String
        Return Str.Trim.Substring(1, Str.Length - 2)
    End Function

    Private Function SplitJSON(ByVal str As String) As String()

        Dim ret() As String = Nothing
        Dim sqCount As Integer = 0
        Dim clCount As Integer = 0
        Dim buildStr As New System.Text.StringBuilder

        For i As Integer = 0 To str.Length - 1
            Select Case str.Substring(i, 1)
                Case ","
                    If sqCount = 0 And clCount = 0 Then
                        Try
                            ReDim Preserve ret(UBound(ret) + 1)
                        Catch ex As Exception
                            ReDim ret(0)
                        Finally
                            ret(UBound(ret)) = buildStr.ToString
                            buildStr = New System.Text.StringBuilder
                        End Try
                    Else
                        buildStr.Append(str.Substring(i, 1))
                    End If
                Case Else
                    buildStr.Append(str.Substring(i, 1))
                    Select Case str.Substring(i, 1)
                        Case "["
                            sqCount += 1
                        Case "]"
                            sqCount -= 1
                        Case "{"
                            clCount += 1
                        Case "}"
                            clCount -= 1

                    End Select
            End Select
        Next
        If buildStr.ToString.Length > 0 Then
            Try
                ReDim Preserve ret(UBound(ret) + 1)
            Catch ex As Exception
                ReDim ret(0)
            Finally
                ret(UBound(ret)) = buildStr.ToString
            End Try
        End If
        Return ret

    End Function

#End Region

End Class