如果类中的目标已初始化，则newtonsoft json将有效日期时间反序列化为可空的日期时间偏移不同的行为

Question

Newtonsoft JSON今天从NuGet（我认为是V12），.NET框架V4.7.2，web服务返回的简化示例中提取。代码和输出如下。所有返回的日期时间表单均声明为UTC。当反序列化为类的datetimeoffset成员时，是否有反序列化设置选项将无时区信息视为UTC？样本返回值为“2015-08-04T22:04:50”

如果datetimeoffset成员未标记为可空，则不带时区的可分析datetimeoffset将返回默认的未初始化值(1/1/0001 12:00:00 AM 00:00)。换句话说，反序列化不成功。用DateTimeOffset分析时，字符串相同。Parse将其视为本地时区，并返回本地时区中的有效日期时间。不好，但是可以用其他代码处理。

如果date时间偏移成员被标记为可空，则该成员保持为空（无），这也是不正确的。

类中日期时间偏移量的初始化值： 8/4/2015 10：04：50 PM 00：00

纽顿软件。JSON . JSON convert . serialize object序列化字符串:{ " dtore turned ":" 2015-08-04t 22:04:50 00:00 " }

来自web服务的序列化字符串:{ " dtore turned ":" 2015-08-04t 22:04:50 " }

datetimeoffset的取消排序值：8/4/2015 10:04:50 PM 00:00

类中未初始化的datetimeoffset值:1/1/0001 12:00:00 AM 00:00

datetimeoffset的非序列化值:1/1/0001 12:00:00 AM 00:00

类中datetimeoffset的初始化值：8/4/2025 10:04:50 PM 00:00

纽顿软件。JSON . JSON convert . serialize object序列化字符串:{ " dtore turned ":" 2025-08-04t 22:04:50 00:00 " }

来自web服务的序列化字符串:{ " dtore turned ":" 2025-08-04t 22:04:50 " }

datetimeoffset的非序列化值:2025年8月4日10:04:50 PM 00:00

反序列化前类中日期时间偏移量的值为无

类中datetimeoffset的deserialzied值为空

进口系统。IO公共类表单1

Private Sub Form1_Load(sender As Object, e As EventArgs) Handles Me.Load
    Dim obj1a As New TestClass1 ' transfers_v1_incoming
    obj1a.dtoReturned = DateTimeOffset.Parse("2015-08-04T22:04:50Z")
    Debug.Print("initialized value of datetimeoffset in class: " & obj1a.dtoReturned.ToString)
    Dim strIn As String = Newtonsoft.Json.JsonConvert.SerializeObject(obj1a)
    Debug.Print("Newtonsoft.Json.JsonConvert.SerializeObject serialized string: " & strIn)
    strIn = Replace(strIn, "+00:00", "")
    Debug.Print("serialized string from web service: " & strIn)

    Newtonsoft.Json.JsonConvert.DeserializeObject(strIn, obj1a.GetType)
    Debug.Print("deserialzied value of datetimeoffset: " & obj1a.dtoReturned.ToString)

    Dim obj1b As New TestClass1 ' transfers_v1_incoming
    Debug.Print("uninitialized value of datetimeoffset in class: " & obj1b.dtoReturned.ToString)

    Newtonsoft.Json.JsonConvert.DeserializeObject(strIn, obj1b.GetType)
    Debug.Print("deserialzied value of datetimeoffset: " & obj1b.dtoReturned.ToString)

    Dim obj2a As New TestClass2
    obj2a.dtoReturned = DateTimeOffset.Parse("2025-08-04T22:04:50Z")
    Debug.Print("initialized value of datetimeoffset in class: " & obj2a.dtoReturned.ToString)
    strIn = Newtonsoft.Json.JsonConvert.SerializeObject(obj2a)
    Debug.Print("Newtonsoft.Json.JsonConvert.SerializeObject serialized string: " & strIn)
    strIn = Replace(strIn, "+00:00", "")
    Debug.Print("serialized string from web service: " & strIn)
    Newtonsoft.Json.JsonConvert.DeserializeObject(strIn, obj2a.GetType)
    Debug.Print("deserialzied value of datetimeoffset: " & obj2a.dtoReturned.ToString)

    Dim obj2b As New TestClass2
    If IsNothing(obj2b.dtoReturned) Then
        Debug.Print("value of datetimeoffset in class before deserialize is nothing")
    Else
        Debug.Print("uninitialized value of datetimeoffset in class before deserialize: " & obj2b.dtoReturned.ToString)
    End If

    Newtonsoft.Json.JsonConvert.DeserializeObject(strIn, obj2b.GetType)
    If IsNothing(obj2b.dtoReturned) Then
        Debug.Print("deserialzied value of datetimeoffset in class is nothing")
    Else
        Debug.Print("deserialzied value of datetimeoffset: " & obj2b.dtoReturned.ToString)
    End If

End Sub

Class TestClass1
    Public Property dtoReturned As DateTimeOffset
End Class
Class TestClass2
    Public Property dtoReturned As DateTimeOffset?
End Class

结束类

Answer 1

您正在调用Newtonsoft.Json.JsonConvert。反序列化对象（strIn，obj.GetType），就好像它要变异obj变量一样。不会的。

相反，您需要使用从该方法返回的对象。您还需要将它强制转换到您的类中。

obj = CType(Newtonsoft.Json.JsonConvert.DeserializeObject(strIn, obj.GetType), TestClass1)

或者更简单，使用采用泛型类型定义的重载：

obj = Newtonsoft.Json.JsonConvert.DeserializeObject(Of TestClass1)(strIn)