无法将当前 JSON 对象（例如 {"name":"value"}）反序列化为类型 'System.Collections.Generic.List答案

【问题标题】：Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'System.Collections.Generic.List无法将当前 JSON 对象（例如 {"name":"value"}）反序列化为类型 'System.Collections.Generic.List
【发布时间】：2015-09-24 14:14:32
【问题描述】：

我有以下代码

public async Task<ActionResult> GetExtendedProperties()
        {
            Uri serviceRoot = new Uri(SettingsHelper.AzureAdGraphApiEndPoint);
            var token = AppToken.GetAppToken();
            var adClient = AuthenticationHelper.GetActiveDirectoryClient();

            Microsoft.Azure.ActiveDirectory.GraphClient.Application app = (Microsoft.Azure.ActiveDirectory.GraphClient.Application)adClient.Applications.Where(
                a => a.AppId == SettingsHelper.ClientId).ExecuteSingleAsync().Result;
            if (app == null)
            {
                throw new ApplicationException("Unable to get a reference to application in Azure AD.");
            }

            string requestUrl = string.Format("https://graph.windows.net/{0}/applications/{1}/extensionProperties?api-version=1.5", SettingsHelper.Tenant, app.ObjectId);

            HttpClient hc = new HttpClient();
            hc.DefaultRequestHeaders.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue(
                "Bearer", token);

            HttpResponseMessage hrm = await hc.GetAsync(new Uri(requestUrl));

            if (hrm.IsSuccessStatusCode)
            {
                string jsonresult = await hrm.Content.ReadAsStringAsync();


                return View();
            }
            else
            {
                return View();
            }
        }

它会返回这个字符串

{"odata.metadata":"https://graph.windows.net/mysaasapp.onmicrosoft.com/$metadata#directoryObjects/Microsoft.DirectoryServices.ExtensionProperty","value":[{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"f751a646-2cc1-4e30-bfc6-a8217c0ce0a3","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_Modulos","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]},{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"80aabe1b-b020-41d1-bd2d-cc04af264fe5","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_ModulesPerUser","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]},{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"6e3d7592-7a66-4792-b408-891251197868","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_Comasdasa3dsdaspInfo","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]},{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"93a26374-4135-4f29-9f24-4154522449ec","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_CompInfo","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]},{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"21a8a3d4-f4b4-45b4-8d07-55d450db35f2","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_CompanyNameForSaasApp","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]},{"odata.type":"Microsoft.DirectoryServices.ExtensionProperty","objectType":"ExtensionProperty","objectId":"7b3109e0-8710-4d1a-81c3-2b6a83fb62ee","deletionTimestamp":null,"appDisplayName":"","name":"extension_33e037a7b1aa42ab96936c22d01ca338_Compania","dataType":"String","isSyncedFromOnPremises":false,"targetObjects":["User"]}]}

使用 json2charp，我创建了这个类：

public class ActiveDirectorySchemaExtension
    {
        public string objectType { get; set; }
        public string objectId { get; set; }
        public object deletionTimestamp { get; set; }
        public string appDisplayName { get; set; }
        public string name { get; set; }
        public string dataType { get; set; }
        public bool isSyncedFromOnPremises { get; set; }
        public List<string> targetObjects { get; set; }
    }

如何将该字符串转换为 List 以便在视图上轻松操作它？

更新：我试过这个：

 List<ActiveDirectorySchemaExtension> tmp = JsonConvert.DeserializeObject<List<ActiveDirectorySchemaExtension>>(jsonresult);

但我得到了这个

无法反序列化当前 JSON 对象（例如 {"name":"value"}）输入类型 'System.Collections.Generic.List`1[CapatechSaasApp.Areas.GlobalAdmin.Models.ActiveDirectorySchemaExtension]' 因为该类型需要一个 JSON 数组（例如 [1,2,3]）来反序列化正确。要修复此错误，请将 JSON 更改为 JSON 数组（例如 [1,2,3]）或更改反序列化类型，使其成为正常的 .NET 类型（例如，不是像整数这样的原始类型，也不是集合可以从 JSON 反序列化的数组或列表等类型目的。 JsonObjectAttribute 也可以添加到类型中来强制它从 JSON 对象反序列化。路径 '['odata.metadata']'，第 1 行，第 18 位。

【问题讨论】：

Newtonsoft JSON Deserialize的可能重复
请看duplicate
完全不重复，问题很具体，deserialize会转成对象，我需要转成List of objects
本质上是一样的。请记住，List 也是一个对象。
这不起作用，请参阅更新

标签： c# .net json asp.net-mvc

【解决方案1】：

你在 json2csharp 中忘记了你的父对象。

Demo on .NETFiddle

using System;
using System.Collections.Generic;
using Newtonsoft.Json;

public class ActiveDirectorySchemaExtension // You can switch from the original class name to yours
{
    public string Type { get; set; }        // You should switch to PascalCase to respect C# notation
    public string ObjectType { get; set; }
    public string ObjectId { get; set; }
    public object DeletionTimestamp { get; set; }
    public string AppDisplayName { get; set; }
    public string Name { get; set; }
    public string DataType { get; set; }
    public bool IsSyncedFromOnPremises { get; set; }
    public List<string> TargetObjects { get; set; }
}

public class RootObject
{
    public string Metadata { get; set; }
    public List<ActiveDirectorySchemaExtension> Value { get; set; }
}

public void Main()
{
    var json = "{'odata.metadata':'https://graph.windows.net/mysaasapp.onmicrosoft.com/$metadata#directoryObjects/Microsoft.DirectoryServices.ExtensionProperty','value':[{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'f751a646-2cc1-4e30-bfc6-a8217c0ce0a3','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_Modulos','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']},{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'80aabe1b-b020-41d1-bd2d-cc04af264fe5','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_ModulesPerUser','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']},{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'6e3d7592-7a66-4792-b408-891251197868','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_Comasdasa3dsdaspInfo','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']},{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'93a26374-4135-4f29-9f24-4154522449ec','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_CompInfo','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']},{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'21a8a3d4-f4b4-45b4-8d07-55d450db35f2','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_CompanyNameForSaasApp','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']},{'odata.type':'Microsoft.DirectoryServices.ExtensionProperty','objectType':'ExtensionProperty','objectId':'7b3109e0-8710-4d1a-81c3-2b6a83fb62ee','deletionTimestamp':null,'appDisplayName':'','name':'extension_33e037a7b1aa42ab96936c22d01ca338_Compania','dataType':'String','isSyncedFromOnPremises':false,'targetObjects':['User']}]}";
    var o = JsonConvert.DeserializeObject<RootObject>(json);
    Console.WriteLine(o.Value[0].Name);
}

输出：

extension_33e037a7b1aa42ab96936c22d01ca338_Modulos

【讨论】：

【解决方案2】：

你可以使用 DataContractSerializer

var serializer = new DataContractJsonSerializer(typeof(RootObject));
var ms = new MemoryStream(Encoding.Unicode.GetBytes(json));
var root = serializer.ReadObject(ms) as RootObject;

但你也应该用 [DataContract] 属性标记你的类，用 [DataMember] 属性标记成员。

像这样：

 [DataContract]
    public class RootObject
    {
        [DataMember(Name = "odata.metadata")]
        public string metadata { get; set; }
        [DataMember]
        public List<ActiveDirectorySchemaExtension> value { get; set; }
    }

此外，您在 ActiveDirectorySchemaExtension 类中丢失了一个字段 - odataType。你可以像这样反序列化它：

[DataMember(Name = "odata.type")]
public string odataType { get; set; }

【讨论】：