如何在asp.net core中startup.cs文件的配置方法中更改范圍服務的屬性值

Question

我將在 startup.cs 文件中為我的范圍服務更改或插入一些值。

這是我的代碼。

我正在為 MyService.SomeData 屬性插入一個值。 但是，在查看頁面中，打印空值。

這是為什么？

啟動文件

namespace MyProject
{
    public class Startup
    {
        .
        .
        .
        public void ConfigureServices(IServiceCollection services)
        {
            .
            .
            .
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddScoped<MyService>();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            var scope = app.ApplicationServices.CreateScope();
            var MyService = scope.ServiceProvider.GetService<MyService>();
            app.Use(async (context, next) => 
            {
                if (context.Request.Query.ContainKey("conditionKey") && context.Request.Query["conditonKey"] == "something")
                {
                    MyService.SomeData = "foo";
                }
            });
        }
    }
}

我的服務.cs

namespace MyProject.Service
{
    public class MyService
    {
        public string SomeData { get; set; } = "";
    {
}

我的視圖.cshtml

@inject MyProject.Service.MyService MyService
<!DOCTYPE html>
<html lang="en">
<head>
</head>
<body>
    <div>@MyService.SomeData</div>
</body>

Answer 1

ASP.NET Core 管道為每個 http 請求創建作用域，因此您需要在操作方法中設置此屬性

public class HomeController : Controller
{
    private readonly MyService myService;

    public HomeController(MyService myService)
    {
        this.myService = myService;
    }

    public IActionResult Index()
    {
        myService.MyData = "MyData";

        return View();
    }
}

或者將您的服務注冊為單身人士

public void ConfigureServices(IServiceCollection services)
{
    services.AddSingleton<MyService>();
}


public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    var scope = app.ApplicationServices.CreateScope();
    var MyService = scope.ServiceProvider.GetService<MyService>();

    MyService.MyData = "SomeData";
}

或注冊自定義過濾器並將其集成到管道中

public void ConfigureServices(IServiceCollection services)
{
    services.AddControllersWithViews(x => x.Filters.Add(typeof(MyServiceFilter)));

    services.AddScoped<MyService>();
}


public class MyServiceFilter : IActionFilter
{
    private readonly MyService myService;

    public MyServiceFilter(MyService myService)
    {
        this.myService = myService;
    }

    public void OnActionExecuted(ActionExecutedContext context)
    {
    }

    public void OnActionExecuting(ActionExecutingContext context)
    {
        myService.MyData = "MyData";
    }
}

最后，使用app.Use

app.Use(async (context, next) =>
{
    if (context.Request.Query.ContainsKey("conditionKey") && context.Request.Query["conditionKey"] == "something")
    {
        var myService = context.RequestServices.GetService<MyService>();

        myService.MyData = "foo";
    }

    await next();
});

Answer 2

感謝@YegorAndrosov，我解決了它。 在 app.Use() 中間件中創建請求范圍的服務。 並且，通過 context.RequestServices.GetService(); 創建它

namespace MyProject
{
    public class Startup
    {
        .
        .
        .
        public void ConfigureServices(IServiceCollection services)
        {
            .
            .
            .
            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddScoped<MyService>();
        }
        .
        .
        .
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env, ILogger<Startup> logger)
        {
            .
            .
            .
            app.Use(async (context, next) =>
            {
                var RequestData = context.RequestServices.GetService<RequestData>();
                var HompageSetting = context.RequestServices.GetService<HomepageSetting>();
                if (context.Request.Query.ContainKey("conditionKey") && context.Request.Query["conditonKey"] == "something")
                {
                    MyService.SomeData = "foo";
                }
                await next();
            });
        }
    }
}

如何在asp.net core中startup.cs文件的配置方法中更改范圍服務的屬性值

問題描述

2 個解決方案

解決方案1
2 已采納 2020-10-29 07:04:26

解決方案2
0 2020-10-30 01:48:56

如何在asp.net core中startup.cs文件的配置方法中更改范圍服務的屬性值

問題描述

2 個解決方案

解決方案1 2 已采納 2020-10-29 07:04:26

解決方案2 0 2020-10-30 01:48:56

解決方案1
2 已采納 2020-10-29 07:04:26

解決方案2
0 2020-10-30 01:48:56