我正在尝试从REST Api响应中反序列化JSON字符串，然后在Xamarin.forms中的ListView上显示它。这是到目前为止我得到的：
-TheMainPage.xaml.cs，在此我连接到api并（应该）反序列化响应。
-MainPage.xaml，我在其中创建了要显示的ListView。
-UserModel.cs，用于存储我从API接收的JSON模型（在此处粘贴JSON：https://app.quicktype.io/以获得类）。
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net.Http;
using System.Net.Http.Headers;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms;
using RESTListView;
namespace RESTListViewApp
{
public partial class MainPage : ContentPage
{
public MainPage()
{
InitializeComponent();
GETRequest();
}
private async void GETRequest()
{
HttpClient client = new HttpClient();
client.DefaultRequestHeaders.Clear();
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.TryAddWithoutValidation("Content-Type", "application/json");
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", "dXNlcjQyMzIxNTQwMzMwMjI0OmE2YTZjZDMyLWQ4NTItNGZlNS04NmMxLWE3NTFhMWUyNmZlNA==");
string url = "https://shared-sandbox-api.marqeta.com/v3/users";
var result = await client.GetAsync(url);
var json = result.Content.ReadAsStringAsync().Result;
Users model = Users.FromJson(json);
MyListView.ItemsSource = model;
}
}
}
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:local="clr-namespace:RESTListViewApp"
x:Class="RESTListViewApp.MainPage">
<StackLayout>
<StackLayout HorizontalOptions="Center">
<Button Text="ADD"/>
<Button Text="DELETE"/>
</StackLayout>
<ListView x:Name="MyListView" HasUnevenRows="True">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout HorizontalOptions="Center">
<Label Text="{Binding Token}"/>
<Label Text="{Binding FirstName}"/>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
</StackLayout>
</ContentPage>
// <auto-generated />
//
// To parse this JSON data, add NuGet 'Newtonsoft.Json' then do:
//
// using RESTListView;
//
// var users = Users.FromJson(jsonString);
namespace RESTListView
{
using System;
using System.Collections.Generic;
using System.Globalization;
using Newtonsoft.Json;
using Newtonsoft.Json.Converters;
public partial class Users
{
[JsonProperty("count")]
public long Count { get; set; }
[JsonProperty("start_index")]
public long StartIndex { get; set; }
[JsonProperty("end_index")]
public long EndIndex { get; set; }
[JsonProperty("is_more")]
public bool IsMore { get; set; }
[JsonProperty("data")]
public Datum[] Data { get; set; }
}
public partial class Datum
{
[JsonProperty("token")]
public string Token { get; set; }
[JsonProperty("active")]
public bool Active { get; set; }
[JsonProperty("first_name", NullValueHandling = NullValueHandling.Ignore)]
public string FirstName { get; set; }
[JsonProperty("email")]
public string Email { get; set; }
[JsonProperty("phone", NullValueHandling = NullValueHandling.Ignore)]
public string Phone { get; set; }
[JsonProperty("parent_token", NullValueHandling = NullValueHandling.Ignore)]
public Guid? ParentToken { get; set; }
[JsonProperty("uses_parent_account")]
public bool UsesParentAccount { get; set; }
[JsonProperty("corporate_card_holder")]
public bool CorporateCardHolder { get; set; }
[JsonProperty("company", NullValueHandling = NullValueHandling.Ignore)]
public string Company { get; set; }
[JsonProperty("created_time")]
public DateTimeOffset CreatedTime { get; set; }
[JsonProperty("last_modified_time")]
public DateTimeOffset LastModifiedTime { get; set; }
[JsonProperty("business_token", NullValueHandling = NullValueHandling.Ignore)]
public Guid? BusinessToken { get; set; }
[JsonProperty("metadata")]
public Metadata Metadata { get; set; }
[JsonProperty("account_holder_group_token")]
public string AccountHolderGroupToken { get; set; }
[JsonProperty("status")]
public string Status { get; set; }
}
public partial class Metadata
{
}
public partial class Users
{
public static Users FromJson(string json) => JsonConvert.DeserializeObject<Users>(json, RESTListView.Converter.Settings);
}
public static class Serialize
{
public static string ToJson(this Users self) => JsonConvert.SerializeObject(self, RESTListView.Converter.Settings);
}
internal static class Converter
{
public static readonly JsonSerializerSettings Settings = new JsonSerializerSettings
{
MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
DateParseHandling = DateParseHandling.None,
Converters =
{
new IsoDateTimeConverter { DateTimeStyles = DateTimeStyles.AssumeUniversal }
},
};
}
}
{
"count" : 5,
"start_index" : 0,
"end_index" : 4,
"is_more" : true,
"data" : [ {
"token" : "9dd1c8bd-9de8-4c36-8f33-d088f843b053",
"active" : true,
"first_name" : "Dhd Fh",
"email" : "TEMPORARY_5cab6e5f-8d8c-44f2-aa4a-ad3d1caed890_ffg@ff.gg",
"phone" : "+375291766633",
"parent_token" : "1074bcd0-8e92-4158-8edf-71b6039c7059",
"uses_parent_account" : true,
"corporate_card_holder" : false,
"company" : " fggg",
"created_time" : "2018-11-19T07:11:33Z",
"last_modified_time" : "2018-11-19T07:11:33Z",
"business_token" : "1074bcd0-8e92-4158-8edf-71b6039c7059",
"metadata" : { },
"account_holder_group_token" : "DEFAULT_AHG",
"status" : "ACTIVE"
}, {
"token" : "c26623b3-e1ac-47d5-82b5-890771cb5450",
"active" : true,
"first_name" : "Dhd Fh",
"email" : "TEMPORARY_2f34b134-1b76-4a69-a4c3-945d971cf70a_fud@dhd.dhd",
"phone" : "+375291766633",
"parent_token" : "85b279c6-4c3a-45cd-8a8c-c7c361f5b413",
"uses_parent_account" : true,
"corporate_card_holder" : false,
"company" : "fjf",
"created_time" : "2018-11-19T07:07:33Z",
"last_modified_time" : "2018-11-19T07:07:33Z",
"business_token" : "85b279c6-4c3a-45cd-8a8c-c7c361f5b413",
"metadata" : { },
"account_holder_group_token" : "DEFAULT_AHG",
"status" : "ACTIVE"
}, {
"token" : "B$_C_zlq3yedu",
"active" : true,
"email" : "B$_C_zlq3yedu@square.invalid",
"uses_parent_account" : false,
"corporate_card_holder" : false,
"created_time" : "2018-11-19T05:16:52Z",
"last_modified_time" : "2018-11-19T05:16:52Z",
"metadata" : { },
"account_holder_group_token" : "DEFAULT_AHG",
"status" : "ACTIVE"
}, {
"token" : "B$_C_svutldl3",
"active" : true,
"email" : "B$_C_svutldl3@square.invalid",
"uses_parent_account" : false,
"corporate_card_holder" : false,
"created_time" : "2018-11-19T04:50:18Z",
"last_modified_time" : "2018-11-19T04:50:18Z",
"metadata" : { },
"account_holder_group_token" : "DEFAULT_AHG",
"status" : "ACTIVE"
}, {
"token" : "B$_C_4wzzylny",
"active" : true,
"email" : "B$_C_4wzzylny@square.invalid",
"uses_parent_account" : false,
"corporate_card_holder" : false,
"created_time" : "2018-11-19T04:11:13Z",
"last_modified_time" : "2018-11-19T04:11:13Z",
"metadata" : { },
"account_holder_group_token" : "DEFAULT_AHG",
"status" : "ACTIVE"
} ]
}
但是当我运行程序时，出现以下错误：Newtonsoft.Json.JsonSerializationException: Cannot deserialize the current JSON object (e.g. {"name":"value"}) into type 'RESTListView.Users[]' because the type requires a JSON array (e.g. [1,2,3]) to deserialize correctly.To fix this error either change the JSON to a JSON array (e.g. [1,2,3]) or change the deserialized type so that it is a normal .NET type (e.g. not a primitive type like integer, not a collection type like an array or List<T>) that can be deserialized from a JSON object.
https://i.stack.imgur.com/dtxr5.png [异常图片]
在实现此目标方面的任何帮助将不胜感激。
答案 0 :(得分：1)
您的ItemsSource必须是IEnumerable（即集合或列表）。
Users model = Users.FromJson(json);
List<Users> users = new List<Users>();
users.Add(model);
MyListView.ItemsSource = users;
答案 1 :(得分：0)
尝试像这样的列表视图绑定：
Users model = Users.FromJson(json);
MyListView.ItemsSource = model.Data;
并替换您的局部类，例如：
public partial class Users
{
[JsonProperty("count")]
public long Count { get; set; }
[JsonProperty("start_index")]
public long StartIndex { get; set; }
[JsonProperty("end_index")]
public long EndIndex { get; set; }
[JsonProperty("is_more")]
public bool IsMore { get; set; }
[JsonProperty("data")]
public List<Datum> Data { get; set; }
}