c# - 如何在 Windows Phone 7 中为 JSON Web 服务结果创建类？

Question

如何为 JSON Web 服务结果创建类？这是我从 google api 获得的 JSON 结果。那么，如何为这个 JSON 对象创建类和反序列化。

我创建了一个类来反序列化这个 JSON 对象，

string mapdetail = e.Result;
        var djosn = new DataContractJsonSerializer(typeof(mapResult));
        var mstr = new MemoryStream(Encoding.UTF8.GetBytes(mapdetail));
        mapResult reslt = (mapResult)djosn.ReadObject(mstr);

map 结果类:

[DataContract]
public class mapResult
{
    [DataMember]
    public string status
    {
        get;
        set;
    }
    [DataMember]
    public IList<Resultdetail> result
    {
        get;
        set;
    }
}

所以我创建了结果详细信息和其他列表:

[DataContract]
public class Resultdetail
{
    [DataMember]
    public List<string> types
    {
        get;
        set;
    }
    [DataMember]
    public string formatted_address
    {
        get;
        set;
    }
    [DataMember]
    public List<object> address_components
    {
        get;
        set;
    }
    [DataMember]
    public List<Geometry> geometry
    {
        get;
        set;
    }

}

[DataContract]
public class Geometry
{
    [DataMember]
    public List<GeoLocation> location
    {
        get;
        set;
    }
    [DataMember]
    public string location_type
    {
        get;
        set;
    }
    [DataMember]
    public List<object> viewport
    {
        get;
        set;
    }
    [DataMember]
    public List<object> bounds
    {
        get;
        set;
    }

}

[DataContract]
public class GeoLocation
{
    [DataMember]
    public double lat
    {
        get;
        set;
    }
    [DataMember]
    public double lng
    {
        get;
        set;
    }

}

现在我得到的是 Null 引用；

Answer 1

您的 DatContract 类存在一些问题。

我在下面更正了这些内容，注释掉了原始行并添加了关于具体错误的评论。

[DataContract]
public class mapResult
{
    [DataMember]
    public string status { get; set; }
    [DataMember]
    //public IList<Resultdetail> result { get; set; }
    // Misspelt property name and use of interface rather than concrete type
    public List<Resultdetail> results { get; set; }
}

[DataContract]
public class Resultdetail
{
    [DataMember]
    public List<string> types { get; set; }
    [DataMember]
    public string formatted_address { get; set; }
    [DataMember]
    public List<object> address_components { get; set; }
    [DataMember]
    //public List<Geometry> geometry { get; set; }
    // Json does not contain an array/list of these
    public Geometry geometry { get; set; }
}

[DataContract]
public class Geometry
{
    [DataMember]
    //public List<GeoLocation> location { get; set; }
    // Json does not contain an array/list of these
    public GeoLocation location { get; set; }
    [DataMember]
    public string location_type { get; set; }
    [DataMember]
    // public List<object> viewport { get; set; }  
    // Json does not contain an array/list of these
    public object viewport { get; set; }
    [DataMember]
    //public List<object> bounds { get; set; }
    // Json does not contain an array/list of these
    public object bounds { get; set; }
}

下面的代码表明这是可行的:

var jsonStr = "{\"status\": \"OK\", \"results\": [ { \"types\": [ \"route\" ], \"formatted_address\": \"7th Main Rd, Koramangala, sengaluru, Karnataka 560034, India\", \"address_components\": [ { \"long_name\": \"7th Main Rd\", \"short_name\": \"7th Main Rd\", \"types\": [ \"route\" ] }, { \"long_name\": \"Koramangala\", \"short_name\": \"Koramangala\", \"types\": [ \"sublocality\", \"political\" ] }, { \"long_name\": \"Bengaluru\", \"short_name\": \"Bengaluru\", \"types\": [ \"locality\", \"political\" ] }, { \"long_name\": \"sengaluru\", \"short_name\": \"sengaluru\", \"types\": [ \"administrative_area_level_2\", \"political\" ] }, { \"long_name\": \"Karnataka\", \"short_name\": \"Karnataka\", \"types\": [ \"administrative_area_level_1\", \"political\" ] }, { \"long_name\": \"India\", \"short_name\": \"IN\", \"types\": [ \"country\", \"political\" ] }, { \"long_name\": \"560034\", \"short_name\": \"560034\", \"types\": [ \"postal_code\" ] }],\"geometry\": { \"location\":{ \"lat\": 12.9259085, \"lng\": 77.6334715 }, \"location_type\": \"GEOMETRIC_CENTER\", \"viewport\": { \"southwest\": { \"lat\": 12.9227118, \"lng\": 77.6301852 }, \"northeast\": { \"lat\": 12.929007, \"lng\": 77.6364805}}, \"bounds\": { \"southwest\": { \"lat\": 12.9247615, \"lng\": 77.6330486 },\"northeast\": { \"lat\": 12.9269574, \"lng\": 77.6336171 }}}}]}";

// If using json.net (http://json.codeplex.com/)
var des = JsonConvert.DeserializeObject<mapResult>(jsonStr);

// If using System.Runtime.Serialization.Json
var djosn = new DataContractJsonSerializer(typeof(mapResult));
var mstr = new MemoryStream(Encoding.UTF8.GetBytes(jsonStr));
des = (mapResult)djosn.ReadObject(mstr);

var latitude = des.results[0].geometry.location.lat;
var longitude = des.results[0].geometry.location.lng;

请注意，我的代码仅使用您的示例 json 对象进行了测试，不能保证适用于网络服务返回的所有内容。您还对 object 进行了很多反序列化，如果您想要的不仅仅是纬度和经度，使用起来可能会很尴尬。