GET到的WebAPI调用(GET calls to WebAPI)

我有一个XML响应到Web API的调用问题。具体而言，我有一个功能“的GetValue”打电话，当我要以XML格式为基础，以ID或类“Cellulare”或类“Televisore”返回。

问题是，如果我从浏览器的请求，给了我下面的错误：

<Message>An error has occurred.</Message>
<ExceptionMessage>
The 'ObjectContent`1' type failed to serialize the response body for content type 'application/xml; charset=utf-8'.
</ExceptionMessage>

这是例子：

Public Class Cellulare
    Public Property Colore As String
    Public Property SistemaOperativo As String
End Class

Public Class Televisore
    Public Property Colore As String
    Public Property Marca As String
End Class          

Public Function GetValue(ByVal id As Integer) // ' As Cellulare
    If Id = 1 Then    
        Dim MyTelevisore As New Televisore    
        MyTelevisore.Colore = "grigio"
        MyTelevisore.Marca = "lg"
        Return MyTelevisore
    Else            
        Dim MyCellulare As New Cellulare    
        MyCellulare.Colore = "nero"
        MyCellulare.SistemaOperativo = "android"    
        Return MyCellulare
    End If    
End Function

谁能帮我解决这个问题？？？

预先感谢问候多纳托

Answer 1:

我觉得你的做法是错误的。

你有简单的对象返回，可以很容易通过的WebAPI所提供的默认串行处理。

你返回的对象类型应该是IHttpActionResult （webapi2）或HttpResponseMessage 。

我不会去什么@Frank维特建议，原因返回对象本身是不好的做法。特别是在这里你可以通过返回的通用对象IHttpActionResult / HttpResponseMessage 。

你应该这样做：

Public Function GetValue(ByVal id As Integer) As IHttpActionResult
    If Id = 1 Then    
        Dim MyTelevisore As New Televisore    
        MyTelevisore.Colore = "grigio"
        MyTelevisore.Marca = "lg"
        Return Ok(MyTelevisore)
    Else            
        Dim MyCellulare As New Cellulare    
        MyCellulare.Colore = "nero"
        MyCellulare.SistemaOperativo = "android"    
        Return Ok(MyCellulare)
    End If    
End Function