.net - 服务器端 Blazor 不提供 HttpClient 进行注入(inject)

Question

当我尝试注入(inject) HttpClient 时，我在 razor 页面中收到错误:

Unhandled Promise Rejection: Error: System.InvalidOperationException: Cannot provide a value for property 'Http' on type . There is no registered service of type 'System.Net.Http.HttpClient'.

请查看并提供反馈。

Answer 1

如果您给出您想要执行的操作的代码片段，那么回答您的问题会更容易。但是没问题。现在，我将向您展示一个示例，您必须做什么，才能使用 DI 注入(inject)服务。

ChartDataService.cs


namespace MyBlazorApp.Services 
{

  public class ChartDataService: IChartDataService
  {
    public HttpClient httpClient;
    
    public ChartDataService(HttpClient httpClient) 
    {
      this.httpClient = httpClient;
    }

    public async Task < IEnumerable < ChartData >> GetChartData()
    {
      return await httpClient.GetJsonAsync < ChartData[] > ($ "myUri");
    }
  }
}

IChartDataService.cs

namespace MyBlazorApp.Services 
{
  public interface IChartDataService 
  {
    Task < IEnumerable < ChartData >> GetChartData();
  }
}

Startup.cs
// other

public void ConfigureServices(IServiceCollection services) 
{
    services.AddRazorPages();
    services.AddServerSideBlazor();
    // some services
    services.AddHttpClient < IChartDataService, ChartDataService > (client => 
    {
      client.BaseAddress = new Uri(myBaseUri);
    });    
}

MyRazorPage.razor.cs (when using code Behind)

[Inject] private IChartDataService ChartDataService { get; set; }

or in
MyRazorPage.razor

@code
{
[Inject] private IChartDataService ChartDataService { get; set; }
}

then in your code - block or code - behind file u can use something like this,
  for example, in an async function..

protected override async Task OnInitializedAsync() 
{
  chartData = await ChartDataService.MakeChartData();
}