Question

我在database中有两个表，有一对多关系.State有很多Cities.I从数据库中获取这些数据并将relationship转换为c#中对象的逻辑。

将Dictionary<State, List<City>>转换为JSON，然后使用AngularJs显示。

[WebMethod]
[ScriptMethod(ResponseFormat = ResponseFormat.Json)]
public static Dictionary<State, List<City>> GetCitiesState()
{
    List<State> stateList = new List<State>();
    stateList = StateList();
    List<City> cityList = new List<City>();
    cityList = CityList();
    List<City> currentList = new List<City>();

    Dictionary<State, List<City>> dictionary = new Dictionary<State, List<City>>();
    bool found = false;
    foreach (State state in stateList)
    {
        foreach (City city in cityList)
        {
            if (state.Id == city.StateId)
            {
                found = true;
                currentList.Add(city);
            }
        }
        if (found)
        {
            dictionary.Add(state, currentList);
        }
    }
    return dictionary;
}

它给我 500内部服务器错误

{ “消息”：“类型 \ u0027System.Collections.Generic.Dictionary2 [[AngularWeb.State， AngularWeb，版本= 1.0.0.0，文化=中立，公钥=空]，[System.Collections.Generic.List1 [[AngularWeb.City， AngularWeb，Version = 1.0.0.0，Culture = neutral，PublicKeyToken = null]]， mscorlib，版本= 4.0.0.0，文化=中性，不支持PublicKeyToken = b77a5c561934e089] \ u0027 字典的序列化/反序列化，键必须是字符串或对象。“，”StackTrace“：”at System.Web.Script.Serialization.JavaScriptSerializer.SerializeDictionary（IDictionary的 o，StringBuilder sb，Int32 depth，Hashtable objectsInUse， SerializationFormat serializationFormat）\ r \ n at System.Web.Script.Serialization.JavaScriptSerializer.SerializeValueInternal（对象 o，StringBuilder sb，Int32 depth，Hashtable objectsInUse， SerializationFormat serializationFormat，MemberInfo currentMember）\ r \ n 在 System.Web.Script.Serialization.JavaScriptSerializer.SerializeValue（对象 o，StringBuilder sb，Int32 depth，Hashtable objectsInUse， SerializationFormat serializationFormat，MemberInfo currentMember）\ r \ n 在 System.Web.Script.Serialization.JavaScriptSerializer.Serialize（对象 obj，StringBuilder输出，SerializationFormat serializationFormat）\ r \ n at System.Web.Script.Serialization.JavaScriptSerializer.Serialize（对象 obj，SerializationFormat serializationFormat）\ r \ n at System.Web.Script.Services.RestHandler.InvokeMethod（HttpContext的 context，WebServiceMethodData methodData，IDictionary`2 rawParams）\ r \ n 在 System.Web.Script.Services.RestHandler.ExecuteWebServiceCall（HttpContext的 context，WebServiceMethodData methodData）”， “ExceptionType”： “System.ArgumentException”}

我不确定json的正确语法，但我想要显示这样的东西：

STATE
 CITY
 CITY
 CITY
STATE
 CITY
 CITY
 CITY
......

谢谢！

Answer 1

虽然C＃可以Dictionary<object, object>，但Serialization Guide表示：

序列化字典时，字典的键将转换为字符串并用作JSON对象属性名称。为密钥编写的字符串可以通过覆盖密钥类型的ToString（）或通过实现TypeConverter来自定义。在反序列化字典时，TypeConverter还将支持再次转换自定义字符串。

基本上，它说你不能使用State作为关键。你有几个选择。

将州和城市作为Dictionary<string, object>发送，并让前端为您处理关系。
创建一个负责后端关系的匿名类。

这两种方法都记录在这里。

方法1：以Dictionary<string, object>

[WebMethod]
public static string GetCitiesState()
{
    Dictionary<string, object> result = new Dictionary<string, object>();

    List<State> states = StateList();
    List<City> cities = CityList();

    result.Add("states", states);
    result.Add("cities", cities);

    return new JavaScriptSerializer().Serialize(result);
}

方法2：以List<Anonymous Class>

基本思想是创建一个匿名类型对象列表（或者您可以创建自己的类）。您可以拨打new List<object>();。

[WebMethod]
public static string GetCitiesState()
{
    var result = new List<object>();

    //get stateList and cityList
    //etc... your code here etc...
    boolean found=false;
    foreach(State state in stateList)
    {
        var currentState = new {
            id = state.Id,
            state = state.State,
            stateName = state.Name,
            cities = new List<City>()
        };

        foreach(City city in cityList)
        {
            if(city.StateId == state.Id)
            {
                found=true;
                currentState.cities.Add(city);
            }
        }

        if(found )
        { 
        //add it to the running state list,only states that have cities.
        //on this situation it does not make sense because every states have  
        //cities but for extra info                                                                                              
        result.Add(currentState);
        }
    }

    return new JavaScriptSerializer().Serialize(result);
}

c＃转换字典<object，list <object =“”>＆gt;到JSON

1 个答案: