服务器端Blazor不提供HttpClient进行注入 [英] Server-side Blazor does not provide HttpClient for injection

问题描述

当我尝试注入HttpClient时，在剃须刀页面上出现错误:

I get an error in razor page when I try to inject HttpClient:

未处理的承诺拒绝:错误:System.InvalidOperationException:无法为type的属性'Http'提供值.没有类型为"System.Net.Http.HttpClient"的注册服务.

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'.

请仔细检查并提供反馈.

Kindly review and give feedback.

推荐答案

如果您向代码段提供要执行的操作，将更容易回答您的问题.但是没问题.现在，我将向您展示一个示例，您需要执行哪些操作才能使用DI注入服务.

it would be easier to answer your question if you give code-snippets what you are trying to do. But ok. For now I will show you an example what you have to do, to inject a Service with DI.

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();
}

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