我如何与.net Maui中的IhttpClientFactory正确使用DI

Question

我在.net Maui中还没有发现有关HTTPCLIENT的任何信息。

有人知道该服务是否： builder.services.addhttpclient＆lt; imyservice，myService＆gt;（）; 在毛伊岛的启动Mauipragram.cs中可以吗？然后将HTTPClient注入将要使用的位置。我已经尝试了所有事情，但它似乎不起作用。仅添加httpclient的Singleton对我有效，但似乎并不最佳。

ps。：我必须安装nuget软件包microsoft.extensions.http，以便使用AddHttpClient服务。

更新：

工作代码：

mauipragram.cs

builder.Services.AddTransient<Service<Display>, DisplayService>();
builder.Services.AddTransient<Service<Video>, VideoService>();
builder.Services.AddTransient<Service<Image>, ImageService>();
builder.Services.AddTransient<Service<Log>, LogService>();

builder.Services.AddSingleton(sp => new HttpClient() { BaseAddress = new Uri("https://api.myapi.com") });

videosviewmodel.cs使用服务的示例

[INotifyPropertyChanged]
public partial class VideosViewModel
{
    readonly Service<Video> videoService;
    
    [ObservableProperty]
    ObservableCollection<Video> videos;

    [ObservableProperty]
    bool isEmpty;
    
    [ObservableProperty]
    bool isRefreshing;
    
    public VideosViewModel(Service<Video> videoService)
    {
        this.videoService = videoService;
    }

    [ICommand]
    internal async Task LoadVideosAsync()
    {
#if ANDROID || IOS || tvOS || Tizen
        UserDialogs.Instance.ShowLoading("Henter videoer fra databasen...");
#endif
        await Task.Delay(2000);
        
        Videos = new();

        try
        {
            await foreach (Video video in videoService.GetAllAsync().OrderBy(x => x.Id))
            {
                Videos.Add(video);
            }
        }
        catch (Exception ex)
        {
            throw new Exception(ex.Message);
        }
        finally
        {
            IsRefreshing = false;
#if ANDROID || IOS || tvOS
            UserDialogs.Instance.HideLoading();
#endif

            if (Videos.Count is 0)
            {
                IsEmpty = true;
            }
            else
            {
                IsEmpty = false;
            }
        }
    }
    
    [ICommand]
    async Task UploadVideoAsync()
    {
        await Shell.Current.DisplayAlert("Upload en video", "Under opbygning - kommer senere!", "OK");
    }
}

不工作代码：

mauipragram.cs

builder.Services.AddHttpClient<Service<Display>, DisplayService>(sp => sp.BaseAddress = new Uri("https://api.myapi.com"));
builder.Services.AddHttpClient<Service<Video>, VideoService>(sp => sp.BaseAddress = new Uri("https://api.myapi.com"));
builder.Services.AddHttpClient<Service<Image>, ImageService>(sp => sp.BaseAddress = new Uri("https://api.myapi.com"));
builder.Services.AddHttpClient<Service<Log>, LogService>(sp => sp.BaseAddress = new Uri("https://api.myapi.com"));

videosviewmodel.cs 与上述工作代码相同。

具体不起作用的是，我在orderby（x =＆gt; x.id）上获得对象参考异常，特别是在ViewModel中突出显示X.ID。删除Orderby方法不再例外，但是视图没有显示一个随机空帧以外的数据。

Answer 1

请勿使用Builder.Services.AddhttpClient在MAUI中。
使用一个实例。

Answer 2

Builder.Services.AddhttpClient为我工作。这是我设置矿山的方式：在主程序中，我添加了.addhttpclient（）

public static class MauiProgram
{
public static MauiApp CreateMauiApp()
{
    var builder = MauiApp.CreateBuilder();
    builder.Services.AddHttpClient();
    builder
        .UseMauiApp<App>()
        .ConfigureFonts(fonts =>
        {
            fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
            fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
        });

 #if DEBUG
    builder.Logging.AddDebug();
 #endif

    return builder.Build();
}
}

和appshell.xaml，我删除了DataTemplate的定义，使其像这样：

<Shell
    x:Class="MAUIMultiPage.AppShell"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:MAUIMultiPage"
    Shell.FlyoutBehavior="Disabled">

    <TabBar>
        <ShellContent
        x:Name="homepage"
        Title="Home"
         />
        <ShellContent
        x:Name="specialOpsPage"
        Title="Special Ops"
         />

    </TabBar>

</Shell>

请注意，请注意我给ShellContents的X：名称。 DataTemplates在AppShell.xAML背后的代码中定义了，我可以将Func对象与IHTTPCLIENTFACTORY作为DI参数，看起来像这样：

public partial class AppShell : Shell
{
    public AppShell(IHttpClientFactory httpClientFactory)
    {
        InitializeComponent();

        homepage.ContentTemplate = new DataTemplate(() => new MainPage(httpClientFactory));
        specialOpsPage.ContentTemplate = new DataTemplate(() => new SpecialOps(httpClientFactory));
    }
}

对于App类，我们可以注入IHTTPCLIENTFACTORY，它可以将其传递给Appshell：

public partial class App : Application
{
    public App(IHttpClientFactory httpClientFactory)
    {
        InitializeComponent();

        MainPage = new AppShell(httpClientFactory);
    }
}

以及每个人。页面我将在我的github存储库中获得IHTTPCLIENTFACTORY

  public partial class SpecialOps : ContentPage
   {
    private readonly IHttpClientFactory _httpClientFactory;

        public SpecialOps(IHttpClientFactory httpClientFactory)
        {
            InitializeComponent();
            this._httpClientFactory = httpClientFactory;
        }
    
        private async void Button_Clicked(object sender, EventArgs e)
        {
            var httpClient = _httpClientFactory.CreateClient();
            var result = await httpClient.GetAsync("https://dummy.restapiexample.com/api/v1/employees");
            txtResult.Text = await result.Content.ReadAsStringAsync();
        }
    }

一个完整的解决方案：