我正在为我的服务实现PUT，POST和DELETE。但是每次我尝试向服务器发送一些json时，都会收到错误“无法创建抽象类”。我通过DataContractJsonSerializer运行对象的实例，添加__type字段，并将其包装在{“ obj”：mydata}中来生成请求数据。
我可以通过DataContractJsonSerializer来运行它，它期望BaseObj并且可以正常工作：
{"__type":"RepositoryItem:http:\/\/objects\/","Insert_date":null,"Modified_date":null,"insert_by":null,"last_modify_user_id":null,"modified_by":null, "external_id":"1234","internal_id":54322,"school_id":45,"type_name":0, "vendor_id":57}
我的服务合同以
ServiceKnownType属性修饰，列表中包含RepositoryItem和BaseObj。我正在使用jQuery发布
$.ajax({
type: "POST",
url: "http://localhost/slnSDK/service.svc/create/repositoryitem.json?t=" + token,
data: data,
success: function(result) {
$("#input").html(result);
},
error: function(xhr, result, err) {
$("#htmloutput").html(xhr.responseText);
},
dataType: "json",
contentType: "application/json"
});
我暴露了以下端点：
<OperationContract(Action:=Api2Information.Namespace & "createJson")> _
<WebInvoke(Method:="POST", _
BodyStyle:=WebMessageBodyStyle.Bare, _
RequestFormat:=WebMessageFormat.Json, _
responseFormat:=WebMessageFormat.Json, _
UriTemplate:="/create/{objType}.json?t={token}")> _
Function createJson(ByVal objType As String, ByVal obj As BaseObj, ByVal token As String) As Integer
以及以下对象（省略了IBaseObj，因为它可以由其实现者推断）
<DataContract(Namespace:="http://objects/")> _
Public Class RepositoryItem : Inherits BaseObj
' members backing properties have been omitted.
Public Sub New()
...
<DataMember()> _
Public Property type_name() As eType
...
' Override this to expose it as a property on the WebAPI
<DataMember()> _
Public Overrides Property internal_id() As Integer?
...
<DataMember()> _
Public Property external_id() As String
...
<DataMember()> _
Public Property vendor_id() As Integer
...
End Class
<DataContract(Namespace:="http://objects/")> _
<Serializable()> _
Public MustInherit Class BaseObj : Implements IBaseObj
' members backing properties have been omitted.
<DataMember()> _
Public Overridable Property insert_by() As String Implements IBaseObj.Insert_by
...
<DataMember()> _
Public Overridable Property Insert_date() As Nullable(Of Date) Implements IBaseObj.Insert_date
...
<DataMember()> _
Public Overridable Property modified_by() As String Implements IBaseObj.Modified_by
...
<DataMember()> _
Public Overridable Property Modified_date() As Nullable(Of Date) Implements IBaseObj.Modified_date
...
<DataMember()> _
Public Overridable Property last_modify_user_id() As Nullable(Of Integer) Implements IBaseObj.Last_modify_user_id
...
End Class
POST的Fiddler输出：
POST http://localhost/slnSDK/service.svc/create/repositoryitem.json?t= HTTP/1.1
Host: localhost
Connection: keep-alive
Referer: http://localhost/apitest.html
Content-Length: 265
Origin: http://localhost
X-Requested-With: XMLHttpRequest
Content-Type: application/json
Accept: application/json, text/javascript, */*; q=0.01
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.7 (KHTML, like Gecko) RockMelt/0.8.36.79 Chrome/7.0.517.44 Safari/534.7
Accept-Encoding: gzip,deflate,sdch
Accept-Language: en-US,en;q=0.8
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.3
Cookie: ASP.NET_SessionId=ywyooz45mi3c4d55h4ld4bec; x=lHOtsYBHvS/fKE7JQWzFTw==; y=XhfNVfYYQynJrIZ/odWFOg==
{"obj":{"__type":"RepositoryItem:http:\/\/objects\/","Insert_date":null,"Modified_date":null,"insert_by":null,"last_modify_user_id":null,"modified_by":null, "external_id":"1234","internal_id":54322,"school_id":45,"type_name":0, "vendor_id":57}}
您可以提供的任何帮助都会很棒。谢谢！
最佳答案
大量提示，但始终很难进行远程调试，有几点建议：
删除了提琴手小费（如我所见，您正在使用它）
在您的Ajax帖子中：
success: function(result) {
$("#input").html(result);
},
您应该使用result.d获取消息内容。
success: function(result) {
$("#input").html(result.d);
},
在调试消息中，insert_by字段为null，从片段来看，它似乎不可接受null（作为String？而不是String）。