Blazor等待ef核心完成请求 [英] Blazor wait for ef core to finish request

问题描述

所以现在我得到一个

Error: System.InvalidOperationException: A second operation was started on this context before a previous operation completed.

因为blazor似乎不尊重当前请求.

Because blazor doesn't seem to respect the current request.

我正在做的事情是这样的:

What I am doing is something like this:

FirstComponent.razor

FirstComponent.razor

@inject IService _service; // abstracted service that calls EF

<layout> // layout stuff here
  <SecondComponent /> // second blazor component
</layout>

@code {

  protected override async Task OnInitializeAsync()
  {
     var getSomething = await _service.OnInitializedAsync();
  }

}

SecondComponent.razor

SecondComponent.razor

@inject IService _service; // abstracted service that calls EF

@code {

  protected override async Task OnInitializedAsync()
  {
     var getSomething = await _service.GetSomething();
  }

}

---

因此，我将实体拆分为多个子组件以进行编辑.现在我有一个父母".调用所有这些子组件的组件.

---

So I split my entity in to multiple sub-components for editing it. Now I have one "parent" component that calls all these sub-components.

我的 IService 看起来像这样.

public interface IService
{
  public Task<Something> GetSomething();
}

internal class Service : IService
{
  private readonly SomethingRepository _repo;

  public Service(SomethingRepository repo)
  {
     _repo = repo;
  }

  public async Task<Something> GetSomething() => _repo.GetAsync();
}

internal SomethingRepository
{
  private readonly AppDbContext _context;

  public SomethingRepository(AppDbContext context)
  {
    _context = context;
  }

  public async Task<Something> GetAsync() => ...;//implementation of whatever
}

我正在通过 AddDbContext 将我的 AppDbContext 添加到服务集合中，并通过 AddScoped

I am adding my AppDbContext to the service collection with AddDbContext and my services and repositories with AddScoped

推荐答案

将此添加到您的连接字符串"MultipleActiveResultSets = true"

Add this to your connection string "MultipleActiveResultSets=true"

请注意，在编写服务器代码时，我总是在Db服务上使用Transient进行DI.我从一位MS工程师那里学到了这一点，请仔细阅读这里的评论.

As a side note, when writing server code, I always use Transient on my Db services for DI. I learnt this from a MS engineer, go figure, reading the comments here.

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