【发布时间】：2021-07-21 17:29:18
【问题描述】：
我在我的 xamarin 表单 .xaml 中使用 json 序列化的 REST API 显示数据时遇到问题。
Console.WriteLine("测试产品：" + ProductList.Count);确实返回了产品列表 (55) 但它没有查看。
我也有这个错误
[0:] 无法将当前 JSON 对象（例如 {"name":"value"}）反序列化为类型 'System.Collections.ObjectModel.ObservableCollection`1[xxx_xxxxx.Models.Category]' 因为该类型需要正确反序列化的 JSON 数组（例如 [1,2,3]）。 要修复此错误，要么将 JSON 更改为 JSON 数组（例如 [1,2,3]），要么将反序列化类型更改为普通的 .NET 类型（例如，不是像整数这样的原始类型，而不是像这样的集合类型可以从 JSON 对象反序列化的数组或列表。 JsonObjectAttribute 也可以添加到类型中以强制它从 JSON 对象反序列化。 路径“消息”，第 1 行，位置 11。：\tERROR {0}
我不知道是什么问题。
RESTAPIService.cs
public RestAPIService()
{
client = new HttpClient { BaseAddress = new Uri("https://xxx.xxxxxxx.xx/xx/") };
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
}
public async Task<ObservableCollection<Products>> GetProducts()
{
products = new ObservableCollection<Products>();
var token = SecureStorage.GetAsync("AuthKey");
client.DefaultRequestHeaders.Add("www-authentication", await token);
try
{
HttpResponseMessage response = await client.GetAsync("products");
if (response.IsSuccessStatusCode)
{
var content = await response.Content.ReadAsStringAsync();
products = JsonConvert.DeserializeObject<ObservableCollection<Products>>(content);
Console.WriteLine("response products: " + products.Count);
}
}
catch (Exception ex)
{
Debug.WriteLine(@"\tERROR {0}", ex.Message);
}
return products;
}
Products.cs我的模态类
public class ImageFront
{
public string extension { get; set; }
public string name { get; set; }
public string contents { get; set; }
public int size { get; set; }
public string date { get; set; }
public object thumb { get; set; }
public int? width { get; set; }
public int? height { get; set; }
}
public class ImageThumb
{
public string extension { get; set; }
public string name { get; set; }
public string contents { get; set; }
public int size { get; set; }
public string date { get; set; }
public object thumb { get; set; }
public int? width { get; set; }
public int? height { get; set; }
}
public class File
{
public string extension { get; set; }
public string name { get; set; }
public string contents { get; set; }
public int size { get; set; }
public string date { get; set; }
}
public class Product
{
public string id { get; set; }
public string number { get; set; }
public string name { get; set; }
public string indication { get; set; }
public string weight { get; set; }
public string amount { get; set; }
public string kind { get; set; }
public string usage_days { get; set; }
public string usage_dosage { get; set; }
public string usage_how { get; set; }
public string dosage { get; set; }
public string allergie { get; set; }
public string nutrition { get; set; }
public string preserve { get; set; }
public string shelf_distribution { get; set; }
public string shelf_prod_nr { get; set; }
public string shelf_life { get; set; }
public string charge { get; set; }
public string shelf_description { get; set; }
public string webtext { get; set; }
public string daily_dosage { get; set; }
public object ingredients { get; set; }
public object composition { get; set; }
public string factor { get; set; }
public string risk_analysis { get; set; }
public string conclusion { get; set; }
public string color { get; set; }
public string label { get; set; }
public string purchase_price { get; set; }
public double price { get; set; }
public double sales_price { get; set; }
public string tax_rate { get; set; }
public string min_stock { get; set; }
public string category { get; set; }
public string fabrikant_id { get; set; }
public bool archive { get; set; }
public bool active { get; set; }
public string price_original { get; set; }
public string sales_price_original { get; set; }
public int current_stock { get; set; }
public bool stock_warning { get; set; }
public ImageFront image_front { get; set; }
public ImageThumb image_thumb { get; set; }
public List<File> File { get; set; }
}
public class Products
{
public Product Product { get; set; }
}
ProductViewModel.cs
public class ProductViewModel : BaseViewModel
{
private ObservableCollection<Products> products;
public ProductViewModel()
{
ProductList = new ObservableCollection<Products>();
GetProducts();
}
public ObservableCollection<Products> ProductList
{
get { return products; }
set
{
products = value;
OnPropertyChanged();
}
}
public async void GetProducts()
{
ProductList.Clear();
ProductList = await App.RestAPIManager.GetProductsAsync();
Console.WriteLine("test products: " + ProductList.Count);
}
}
ProductPage.xaml
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="xxx_xxxxx.Views.ProductPage"
xmlns:vm="clr-namespace:xxx_xxxxx.ViewModels" xmlns:model="clr-namespace:xxx_xxxxxx.xxxxxx">
<ContentPage.BindingContext>
<vm:ProductViewModel/>
</ContentPage.BindingContext>
<StackLayout>
<CollectionView x:Name="productList"
ItemsSource="{Binding ProductList}"
VerticalScrollBarVisibility="Never"
SelectionMode="Single"
BackgroundColor="LightGray">
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout Padding="10">
<Label Text="{Binding Product.name}"
FontSize="Small"
TextColor="Blue"/>
<Label Text="{Binding Product.price}"
FontSize="Small" />
<Button Text="hoi">
</Button>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
</ContentPage>
【问题讨论】：
-
你的投标表达式应该只是
Text="{Binding name}"等 -
在数据上下文“产品”错误中找不到成员
-
我在 ProductViewModel.cs 中将 ProductList 定义为 public ObservableCollection
ProductList{}。重点是迭代产品并在集合视图中显示它们 -
是的，它是一个 C# 属性
-
是否显示“hoi”按钮？
标签： xamarin xamarin.forms