如何在核心 razor 网站中存储 int userId asp.net

因此，我想在多个页面中获取 int userId。

所有 Razor 页面都继承自类 。在方案中，将“获取 int userid”的 Razor 页面设置为从自定义页面模型继承，如本 SO 文章中所述。PageModel

从基本页面模型继承允许集中代码，否则这些代码将在每个单独的 Razor 页面模型中重复。

继承的类提供对以下内容的访问：DI 服务、 、 等。此外，从基页模型继承的 Razor 页可以访问自定义基页模型中定义的属性。HttpContextUser

下面的示例演示如何使用依赖项注入设置继承的基页模型。

示例注释

• 此示例使用 DI 服务来替代需要访问数据库服务的方案。IConfiguration

• 该属性在继承的基页模型中定义。请注意，该属性是在 Razor 视图页的方法中设置的，因为继承类中的方法使用该对象。此对象在继承类或 Razor 代码隐藏类的构造函数方法中不可用。 一旦代码执行到达该方法，它就可用。UserIdAsIntOnGet()GetUserIdAsInt()HttpContextHttpContextOnGet()

MyBasePageModel.cs

此 C# 类文件可以插入到项目中的任何位置。如果命名空间不是 .using.cshtml.cs[ProjectName].Pages

using Microsoft.AspNetCore.Mvc.RazorPages;

namespace WebApplication1.Pages
{
    public class MyBasePageModel : PageModel // Inherits from 'PageModel'
    {
        private readonly IConfiguration _configuration;

        public int UserIdAsInt { get; set; }

        public MyBasePageModel(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        public int GetUserIdAsInt()
        {
            int? id = HttpContext.Session.GetInt32("UserIdAsInt");
            if (id == null)
            {
                // Get user ID as integer from database
                id = 100; // For sample purpose set 'id' variable to a hardcoded value
                HttpContext.Session.SetInt32("UserIdAsInt", (int)id);
                System.Diagnostics.Debug.WriteLine("User ID retrieved from database");
            }
            else
            {
                System.Diagnostics.Debug.WriteLine("User ID retrieved from session");
            }
            return (int)id;
        }

        public string GetLoggingLevel()
        {
            return _configuration["Logging:LogLevel:Default"].ToString();
        }
    }
}

InheritFromBasePageModel.cshtml.cs

namespace WebApplication1.Pages
{
    public class InheritFromBasePageModelModel : MyBasePageModel // Inherits from the custom 'MyBasePageModel' class
    {
        public string? LoggingLevel { get; set; }

        public InheritFromBasePageModelModel(IConfiguration configuration)
                : base(configuration: configuration)
        {
        }

        public void OnGet()
        {
            UserIdAsInt = GetUserIdAsInt();
            LoggingLevel = GetLoggingLevel();
        }
    }
}

InheritFromBasePageModel.cshtml

@page
@model WebApplication1.Pages.InheritFromBasePageModelModel
@{
}
@section Styles {
    <style>
        p > span {
            font-weight: bold;
        }
    </style>
}
<p>Logging level property from base page model: <span>@Model.LoggingLevel</span></p>
<p>Integer value: <span>@Model.UserIdAsInt</span></p>

程序.cs

// Configure session state
// https://learn.microsoft.com/en-us/aspnet/core/fundamentals/app-state?view=aspnetcore-7.0#configure-session-state
// https://stackoverflow.com/questions/71070698/session-in-asp-net-core-mvc
// "add session middleware in your configuration file"
builder.Services.AddSession(options =>
{
    //options.IdleTimeout = TimeSpan.FromMinutes(1);   
});

app.UseSession();

（编辑 2023 年 11 月 11 日）

使用 OnPageHandlerExecutionAsync（） 重写

上面的基页模型类要求从基页模型继承的每个 Razor 页在方法中添加行。MyBasePageModel.csUserIdAsInt = GetUserIdAsInt();OnGet()

这篇 SO 文章和文章演示如何为从基页模型继承的每个处理程序执行方法，而无需将其添加到每个 Razor 页面。OnGet()

下面是实现重写方法的修改后的类文件。MyBasePageModel.csOnPageHandlerExecutionAsync()

using Microsoft.AspNetCore.Mvc.Filters;
using Microsoft.AspNetCore.Mvc.RazorPages;

namespace WebApplication1.Pages
{
    public class MyBasePageModel : PageModel
    {
        private readonly IConfiguration _configuration;

        public int UserIdAsInt { get; set; }

        public MyBasePageModel(IConfiguration configuration)
        {
            _configuration = configuration;
        }

        // https://stackoverflow.com/questions/55030251/razor-pages-call-method-from-base-class-after-all-onget-handlers
        // https://www.learnrazorpages.com/razor-pages/filters
        // "Model binding completed. Handler has not been executed."
        public async override Task OnPageHandlerExecutionAsync(PageHandlerExecutingContext context, PageHandlerExecutionDelegate next)
        {
            if (context.HandlerMethod?.MethodInfo.Name == "OnGet")
            {
                // Code placed here will execute just before the OnGet()
                // method is executed.
                UserIdAsInt = await GetUserIdAsInt();
            }
            await base.OnPageHandlerExecutionAsync(context, next);
        }

        public async Task<int> GetUserIdAsInt()
        {
            int? id = HttpContext.Session.GetInt32("UserIdAsInt");

            // A valid user ID integer value exists in the 'Session'
            // object. Therefore, return this value.
            if (id != null)
            {
                System.Diagnostics.Debug.WriteLine("User ID retrieved from session");
                return (int)id;
            }

            // Get user ID as integer from database

            // 'Task.Run()' is used to simulate an async execution
            // of a database task.
            return await Task.Run(() =>
            {
                id = 200; // For sample purpose set 'id' variable to a hardcoded value
                HttpContext.Session.SetInt32("UserIdAsInt", (int)id);
                System.Diagnostics.Debug.WriteLine("User ID retrieved from database");
                return (int)id;
            });
        }

        public string? GetLoggingLevel()
        {
            if (_configuration == null) { return "(Configuration does not exist.)"; }
            return _configuration["Logging:LogLevel:Default"]?.ToString() ?? "Unset";
        }
    }
}