json - ServiceStack.Text 读取 json 结果不起作用

Question

我只是想找出反序列化从 3rd 方 api 调用返回的 json 字符串的最佳方法。我读到 ServiceStack 很快，所以想尝试一下。没有经验，这是我所做的：

1. 打开 Visual Studio 2013
2. 创建新项目 Windows 窗体应用程序
3. 安装 ServiceStack.Text（基于https://servicestack.net/download）
4. 添加了一个按钮（btnView）和文本框（txtOutput）

5. 将代码添加到 btnView_Click 事件

          Private Sub btnView_Click(sender As Object, e As EventArgs) Handles btnView.Click
   
       Me.Cursor = Cursors.WaitCursor
   
       Dim wp As New WebPost 'this allows to pass url and return results
       wp.URL = "xxxx"
       Dim sJSONRetVal As String = wp.Request(String.Empty, True)
   'sJSONRetVal return values looks like the following:
   '{"complaints":[{"feedback_type":"abuse","subject":"Sales Agent Position"},{"feedback_type":"abuse","subject":"Sales Agent Position"}],"message":"OK","code":0}
   
   
       'ServiceStack.Text example
       Dim t As SMTP_Complaints = ServiceStack.Text.JsonSerializer.DeserializeFromString(Of SMTP_Complaints)(sJSONRetVal)
   
       'For Each xi As SMTP_Complaints In t
       '    txtOutput.Text &= xi.mail_from & vbCrLf
       'Next
   
       wp = Nothing
   
       txtOutput.Text = t.ToString
   
       Me.Cursor = Cursors.Default
   
   End Sub
   
   Public Class SMTP_Complaints
   
   Dim _feedback_type As String = ""
   Dim _subject As String = ""
   
   Public Property feedback_type As String
       Get
           Return _feedback_type
       End Get
       Set(value As String)
           _feedback_type = value
       End Set
   End Property
   
   Public Property subject As String
       Get
           Return _subject
       End Get
       Set(value As String)
           _subject = value
       End Set
   End Property
   End Class
   

以上似乎没有得到任何数据。我将如何遍历返回的数据并从两个实例返回数据？只是不确定我需要如何设置它来读取 json 数据然后能够输出。

Answer 1

基于返回的 JSON：

{"complaints":[{"feedback_type":"abuse","subject":"Sales Agent Position"},{"feedback_type":"abuse","subject":"Sales Agent Position"}],"message":"OK","code":0}

您将需要两个 DTO 来反序列化此结果。

我在这里使用了自动实现的属性来简化代码的复杂性。如果您使用旧版本的 VB，则需要扩展这些以包含带有 get 和 set 方法的支持字段。

Public Class SMTP_Complaint
    Public Property feedback_type As String
    Public Property subject As String
End Class

Public Class SMTP_ComplaintsResponse
    Public Property complaints As SMTP_Complaint()
    Public Property message As String
    Public Property code As Integer
End Class

您需要该SMTP_ComplaintsResponse课程，因为您的投诉包含在 JSON 响应中。

然后反序列化响应：

Dim response = JsonSerializer.DeserializeFromString(Of SMTP_ComplaintsResponse)(sJSONRetVal)

然后可以访问您的投诉：

For Each complaint As var In response.complaints
    Console.WriteLine("Type: {0}, Subject {1}", complaint.feedback_type, complaint.subject)
Next