Asmx Web 服务如何返回 JSON 而不是 XML？

Question

我的服务方式：

[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public string getDataFromTrainingMaster()
{
    List<TrainingMasterDataStruct> results = new DAL().GetDataFromTrainingMaster();
    JavaScriptSerializer js = new JavaScriptSerializer();                    
    return js.Serialize(results).ToString(); 
}

我的 .net Web 服务返回包装在 XML 中的 JSON，如下所示：

<?xml version="1.0" encoding="UTF-8"?>
<string xmlns="http://tempuri.org/">   [{"Training_Code":"1234 ","Training_Duration":"2hrs ","Training_Startdate":"2/14/2013 3:00:00 PM","Training_Enddate":"2/14/2013 5:00:00 PM","Trainer_ID":1,"Training_Location":"B-Wing Training room-4","Comments":"C# training","Keyword":"C#1234","NumberofDays":1},{"Training_Code":"4321 ","Training_Duration":"16 ","Training_Startdate":"2/17/2013 10:30:00 AM","Training_Enddate":"2/17/2013 5:30:00 PM","Trainer_ID":2,"Training_Location":"A-Wing Training Room-6","Comments":"Objective-C","Keyword":"Obj-C4321","NumberofDays":2}]

我需要以下格式：

"Training":[{"Training_Code":"1234 ","Training_Duration":"2hrs ","Training_Startdate":"2/14/2013 3:00:00 PM","Training_Enddate":"2/14/2013 5:00:00 PM","Trainer_ID":1,"Training_Location":"B-Wing Training room-4","Comments":"C# training","Keyword":"C#1234","NumberofDays":1},{"Training_Code":"4321 ","Training_Duration":"16 ","Training_Startdate":"2/17/2013 10:30:00 AM","Training_Enddate":"2/17/2013 5:30:00 PM","Trainer_ID":2,"Training_Location":"A-Wing Training Room-6","Comments":"Objective-C","Keyword":"Obj-C4321","NumberofDays":2}]</string>

我该怎么做？

Answer 1

无需自己创建 JSON 字符串。返回 List<TrainingMasterDataStruct> 并让 .NET 即时为您序列化它：

[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public List<TrainingMasterDataStruct> getDataFromTrainingMaster()
{
   List<TrainingMasterDataStruct> list = doStuff();
   return list;
}

其次，非静态方法签名表明这是一个 asmx 文件（页面方法是静态的）。默认情况下，这些序列化为 xml，因此您需要取消注释或将 System.Web.Script.Services.ScriptService 属性添加到 Web 服务类：

[WebService(Namespace = "http://tempuri.org/")]
[WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
[System.Web.Script.Services.ScriptService]
public class WebService : System.Web.Services.WebService {

这允许它返回 JSON。一个问题：JSON 序列化器似乎能够序列化比 XML 更多的类型，所以如果你想输出或者/或在这里要小心 - 在这里使用列表和数组而不是集合。

第三，非常重要，客户端必须向服务器表明它需要 JSON 响应。

为了测试和验证第三点，我建议您按照上述步骤，然后使用 jQuery 从测试网页调用 Web 服务并监控 Fiddler 中的流量。比如：

$.ajax({
        type: "POST",
        url: "WebService.asmx/getDataFromTrainingMaster",
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        data: "",
        success: function (msg) { }
    });

这是 JSON 请求/响应的样子 - 请特别注意 POST、Accept 和 Content-Type 标头：

POST http://scrubbed/GetVehicles HTTP/1.1
x-requested-with: XMLHttpRequest
Accept-Language: en-gb
Accept: application/json, text/javascript, */*
Content-Type: application/json; charset=utf-8
Accept-Encoding: gzip, deflate
User-Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 6.1; WOW64; Trident/4.0; SLCC2; .NET CLR 2.0.50727; .NET CLR 3.5.30729; .NET CLR 3.0.30729; .NET4.0C; .NET4.0E; InfoPath.2)
Host: scrubbed
Content-Length: 0
Connection: Keep-Alive
Pragma: no-cache

HTTP/1.1 200 OK
Cache-Control: private, max-age=0
Content-Type: application/json; charset=utf-8
Server: Microsoft-IIS/7.5
X-Powered-By: ASP.NET
Date: Mon, 04 Oct 2010 10:49:12 GMT
Content-Length: 1417

{"d":{"Data":[{"Key":1,"Value":[{"VehicleId":15036,"VehicleAlias":"Whatever","Expiry":"\/Date(1915983035043)\/","Expired":false},{"VehicleId":

Answer 2

尝试将您的返回类型更改为List<TrainingMasterDataStruct> 并返回“results”。您不需要自己序列化字符串，带有 WebMethod 属性的 ASP.NET 会为您解决这个问题。

Answer 3

你可以试试这个：

var data = [{"Training_Code":"1234 ","Training_Duration":"2hrs ","Training_Startdate":"2/14/2013 3:00:00 PM","Training_Enddate":"2/14/2013 5:00:00 PM","Trainer_ID":1,"Training_Location":"B-Wing Training room-4","Comments":"C# training","Keyword":"C#1234","NumberofDays":1},{"Training_Code":"4321 ","Training_Duration":"16 ","Training_Startdate":"2/17/2013 10:30:00 AM","Training_Enddate":"2/17/2013 5:30:00 PM","Trainer_ID":2,"Training_Location":"A-Wing Training Room-6","Comments":"Objective-C","Keyword":"Obj-C4321","NumberofDays":2}]

var result = JSON.stringify({ Training: data })

result 会给你想要的输出。

Answer 4

我遇到了类似的错误。一种方法以正确的 json 格式返回响应，但另一种方法以相同的 asmx 格式返回 xml。

这里有两种方法：

JSON 格式的响应：

[WebMethod]
    [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
    public string loginOne(string param1, string param2){
          result = new JObject();
          ...
          ...
          return result.ToString();
    }

XML 格式的响应：

 [WebMethod]
    [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
    public string getCompaniesOne()
    {
        ...
        ...
        return result.ToString();
    }

我是怎么解决的？

在错误的响应方法中添加一个虚拟参数。

 [WebMethod]
    [ScriptMethod(ResponseFormat = ResponseFormat.Json)]
    public string getCompaniesOne(string dummy)
    {
       ...
       ...
       return result.ToString();
    }       

希望对您有所帮助。