vb.net 使用 Visual Basic 2010 中的对象进行 JSON 编码和解码
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JSON Encode and Decode with objects in Visual Basic 2010
提问by Blease
I have the following code:
我有以下代码：
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq
Module Module1
Structure JSONList
Dim Name, Email As String
Dim Age As Integer
End Structure
Sub Main()
Dim Data(1) As JSONList
Data(0).Name = "Josh"
Data(0).Age = 17
Data(0).Email = "[email protected]"
Data(1).Name = "Greg"
Data(1).Age = 17
Data(1).Email = "[email protected]"
Dim JSONEncode As String
JSONEncode = JsonConvert.SerializeObject(Data)
Console.WriteLine(JSONEncode)
Console.WriteLine()
Console.WriteLine()
Dim JSONDecode() As JSONList = JsonConvert.DeserializeObject(JSONEncode)
Console.WriteLine(JSONDecode(0).Name)
Console.ReadKey()
End Sub
End Module
The first encoding part of the script is used to store the encoded string to a database, the output is:
脚本的第一个编码部分用于将编码后的字符串存储到数据库中，输出为：
[{"Name":"Josh","Email":"[email protected]","Age":17},{"Name":"Greg","Email":"[email protected]","Age":17}]
Now when I try to decode this JSON string, I get an error Unable to cast object of type 'Newtonsoft.Json.Linq.JArray' to type 'JSONList[]'.
现在，当我尝试解码此 JSON 字符串时，出现错误 Unable to cast object of type 'Newtonsoft.Json.Linq.JArray' to type 'JSONList[]'.
I need the data to be encoded in the JSON format so that I can use it in my website that uses PHP to decode it. I am using Visual Basic 2010 along with JSON.NET.
我需要以 JSON 格式对数据进行编码，以便我可以在使用 PHP 对其进行解码的网站中使用它。我正在使用 Visual Basic 2010 和 JSON.NET。
回答by Adrian Wragg
The problem is that JsonConvert.DeserializeObjectdeserialises into an object of type Newtonsoft.Json.Linq.JArraywhich .net cannot automatically convert to an array of JSONList. A little bit of conversion is required:
问题是JsonConvert.DeserializeObject反序列化为Newtonsoft.Json.Linq.JArray.net 无法自动转换为JSONList. 需要一点转换：
Dim jsonObject As Newtonsoft.Json.Linq.JArray =
JsonConvert.DeserializeObject(JSONEncode)
Dim JSONDecode() As JSONList = (
From j In jsonObject
Select New JSONList() With {.Age = j("Age"),
.Email = j("Email"),
.Name = j("Name")}
).ToArray()
回答by Brian Rogers
As @Adrian said, JsonConvert.DeserializeObjectwill deserialize to JArray, which .Net cannot automatically convert into an array of your JSONListstructure. However, you don't need to do manual conversion; you simply need to use the overload of DeserializeObjectwhich accepts a type parameter. This will allow Json.Net to deserialize directly to your type without needing any special conversion code.
正如@Adrian 所说，JsonConvert.DeserializeObject将反序列化为JArray.Net 无法自动转换为您的JSONList结构数组。但是，您不需要进行手动转换；您只需要使用DeserializeObject接受类型参数的重载。这将允许 Json.Net 直接反序列化为您的类型，而无需任何特殊的转换代码。
Dim JSONDecode() As JSONList = _
JsonConvert.DeserializeObject(Of JSONList())(JSONEncode)
