Asp.net core 在httpContextAccessor.HttpContext上返回null

我们重写saveChangesSync（）以自动更新DateCreated、CreatedBy、LastDateModified和LastModifiedBy。使用CreatedBy和LastModifiedBt，我们需要输入标识的用户Id

在ApplicationDbContext的构造函数中，我们添加了如下内容：

\u userName=httpContextAccessor.HttpContext.User.Identity.Name；
//_userID=userManager.GetUserId（httpContext.httpContext.User）

。。并始终在此httpContextAccessor.HttpContext中获取空值。有什么想法吗？我们在下面列出了来源

环境：

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Models;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Linq.Expressions;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;

namespace AthlosifyWebArchery.Data
{
    public class ApplicationDbContext : IdentityDbContext<ApplicationUser, ApplicationRole, string>
    {
        private readonly string _userID;
        private readonly string _userName;


        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options,
                IHttpContextAccessor httpContextAccessor
                )
        : base(options)
        {
            _userName = httpContextAccessor.HttpContext.User.Identity.Name;

            //_userID = userManager.GetUserId(httpContext.HttpContext.User);

        }

        public DbSet<AthlosifyWebArchery.Models.TournamentBatchItem> TournamentBatchItem { get; set; }
        public DbSet<AthlosifyWebArchery.Models.TournamentBatch> TournamentBatch { get; set; }

        public virtual DbSet<AthlosifyWebArchery.Models.Host> Host { get; set; }

        public DbSet<AthlosifyWebArchery.Models.HostApplicationUser> HostApplicationUser { get; set; }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

            foreach (var entityType in builder.Model.GetEntityTypes())
            {
                // 1. Add the IsDeleted property
                entityType.GetOrAddProperty("IsDeleted", typeof(bool));

                // 2. Create the query filter

                var parameter = Expression.Parameter(entityType.ClrType);

                // EF.Property<bool>(post, "IsDeleted")
                var propertyMethodInfo = typeof(EF).GetMethod("Property").MakeGenericMethod(typeof(bool));
                var isDeletedProperty = Expression.Call(propertyMethodInfo, parameter, Expression.Constant("IsDeleted"));

                // EF.Property<bool>(post, "IsDeleted") == false
                BinaryExpression compareExpression = Expression.MakeBinary(ExpressionType.Equal, isDeletedProperty, Expression.Constant(false));

                // post => EF.Property<bool>(post, "IsDeleted") == false
                var lambda = Expression.Lambda(compareExpression, parameter);

                builder.Entity(entityType.ClrType).HasQueryFilter(lambda);
            }


            // Many to Many relationship

            builder.Entity<HostApplicationUser>()
                .HasKey(bc => new { bc.HostID, bc.Id });


            builder.Entity<HostApplicationUser>()
                .HasOne(bc => bc.Host)
                .WithMany(b => b.HostApplicationUsers)
                .HasForeignKey(bc => bc.HostID);

            builder.Entity<HostApplicationUser>()
                .HasOne(bc => bc.ApplicationUser)
                .WithMany(c => c.HostApplicationUsers)
                .HasForeignKey(bc => bc.Id);

        }

        public override int SaveChanges(bool acceptAllChangesOnSuccess)
        {
            OnBeforeSaving();
            return base.SaveChanges(acceptAllChangesOnSuccess);
        }

        public override Task<int> SaveChangesAsync(bool acceptAllChangesOnSuccess, CancellationToken cancellationToken = default(CancellationToken))
        {
            OnBeforeSaving();
            return base.SaveChangesAsync(acceptAllChangesOnSuccess, cancellationToken);
        }

        private void OnBeforeSaving()
        {
            // Added
            var added = ChangeTracker.Entries().Where(v => v.State == EntityState.Added && typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            added.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).DateCreated = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).CreatedBy = _userID;
                ((IBaseEntity)entry.Entity).LastDateModified = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).LastModifiedBy = _userID;
            });

            // Modified
            var modified = ChangeTracker.Entries().Where(v => v.State == EntityState.Modified && 
            typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            modified.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).LastDateModified = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).LastModifiedBy = _userID;
            });

            // Deleted
            //var deleted = ChangeTracker.Entries().Where(v => v.State == EntityState.Deleted &&
            //typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            var deleted = ChangeTracker.Entries().Where(v => v.State == EntityState.Deleted).ToList();

            deleted.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).DateDeleted = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).DeletedBy = _userID;
            });

            foreach (var entry in ChangeTracker.Entries()
                                    .Where(e => e.State == EntityState.Deleted &&
                                    e.Metadata.GetProperties().Any(x => x.Name == "IsDeleted")))
            {
                switch (entry.State)
                {
                    case EntityState.Added:
                        entry.CurrentValues["IsDeleted"] = false;
                        break;

                    case EntityState.Deleted:
                        entry.State = EntityState.Modified;
                        entry.CurrentValues["IsDeleted"] = true;
                        break;
                }
            }
        }
    }



}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Data;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using AthlosifyWebArchery.Models;
using DinkToPdf.Contracts;
using DinkToPdf;

namespace AthlosifyWebArchery
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //services.AddHttpContextAccessor();

            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddSingleton(typeof(IConverter), new SynchronizedConverter(new PdfTools()));

            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));

            // Extended Application User from IdentityUser 
            // and ApplicationRole from IdentityRole

            services.AddIdentity<ApplicationUser, ApplicationRole>(
                options => options.Stores.MaxLengthForKeys = 128)
                .AddEntityFrameworkStores<ApplicationDbContext>()
                .AddDefaultUI()
                .AddDefaultTokenProviders();

            services.AddMvc()
                .AddRazorPagesOptions(options =>
                {
                    options.Conventions.AuthorizeFolder("/Tournaments");
                    options.Conventions.AuthorizeFolder("/TournamentAtheletes");
                    options.Conventions.AuthorizeFolder("/TournamentBatches");
                    options.Conventions.AuthorizeFolder("/TournamentContingents");
                    options.Conventions.AuthorizeFolder("/Admin");
                    //options.Conventions.AuthorizeFolder("/Private");
                    //options.Conventions.AllowAnonymousToPage("/Private/PublicPage");
                    //options.Conventions.AllowAnonymousToFolder("/Private/PublicPages");
                })
                .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
                                ApplicationDbContext context,
                                RoleManager<ApplicationRole> roleManager,
                                UserManager<ApplicationUser> userManager)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseAuthentication();

            app.UseMvc();

            //UserManagerInitialData.Initialize(context, userManager, roleManager).Wait();

        }


    }
}

.NET核心2.1

SQL Server

ApplicationDBContext.cs:

using System;
using System.Collections.Generic;
using System.Text;
using Microsoft.AspNetCore.Identity.EntityFrameworkCore;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Models;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using System.Linq.Expressions;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Identity;

namespace AthlosifyWebArchery.Data
{
    public class ApplicationDbContext : IdentityDbContext<ApplicationUser, ApplicationRole, string>
    {
        private readonly string _userID;
        private readonly string _userName;


        public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options,
                IHttpContextAccessor httpContextAccessor
                )
        : base(options)
        {
            _userName = httpContextAccessor.HttpContext.User.Identity.Name;

            //_userID = userManager.GetUserId(httpContext.HttpContext.User);

        }

        public DbSet<AthlosifyWebArchery.Models.TournamentBatchItem> TournamentBatchItem { get; set; }
        public DbSet<AthlosifyWebArchery.Models.TournamentBatch> TournamentBatch { get; set; }

        public virtual DbSet<AthlosifyWebArchery.Models.Host> Host { get; set; }

        public DbSet<AthlosifyWebArchery.Models.HostApplicationUser> HostApplicationUser { get; set; }

        protected override void OnModelCreating(ModelBuilder builder)
        {
            base.OnModelCreating(builder);

            foreach (var entityType in builder.Model.GetEntityTypes())
            {
                // 1. Add the IsDeleted property
                entityType.GetOrAddProperty("IsDeleted", typeof(bool));

                // 2. Create the query filter

                var parameter = Expression.Parameter(entityType.ClrType);

                // EF.Property<bool>(post, "IsDeleted")
                var propertyMethodInfo = typeof(EF).GetMethod("Property").MakeGenericMethod(typeof(bool));
                var isDeletedProperty = Expression.Call(propertyMethodInfo, parameter, Expression.Constant("IsDeleted"));

                // EF.Property<bool>(post, "IsDeleted") == false
                BinaryExpression compareExpression = Expression.MakeBinary(ExpressionType.Equal, isDeletedProperty, Expression.Constant(false));

                // post => EF.Property<bool>(post, "IsDeleted") == false
                var lambda = Expression.Lambda(compareExpression, parameter);

                builder.Entity(entityType.ClrType).HasQueryFilter(lambda);
            }


            // Many to Many relationship

            builder.Entity<HostApplicationUser>()
                .HasKey(bc => new { bc.HostID, bc.Id });


            builder.Entity<HostApplicationUser>()
                .HasOne(bc => bc.Host)
                .WithMany(b => b.HostApplicationUsers)
                .HasForeignKey(bc => bc.HostID);

            builder.Entity<HostApplicationUser>()
                .HasOne(bc => bc.ApplicationUser)
                .WithMany(c => c.HostApplicationUsers)
                .HasForeignKey(bc => bc.Id);

        }

        public override int SaveChanges(bool acceptAllChangesOnSuccess)
        {
            OnBeforeSaving();
            return base.SaveChanges(acceptAllChangesOnSuccess);
        }

        public override Task<int> SaveChangesAsync(bool acceptAllChangesOnSuccess, CancellationToken cancellationToken = default(CancellationToken))
        {
            OnBeforeSaving();
            return base.SaveChangesAsync(acceptAllChangesOnSuccess, cancellationToken);
        }

        private void OnBeforeSaving()
        {
            // Added
            var added = ChangeTracker.Entries().Where(v => v.State == EntityState.Added && typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            added.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).DateCreated = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).CreatedBy = _userID;
                ((IBaseEntity)entry.Entity).LastDateModified = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).LastModifiedBy = _userID;
            });

            // Modified
            var modified = ChangeTracker.Entries().Where(v => v.State == EntityState.Modified && 
            typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            modified.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).LastDateModified = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).LastModifiedBy = _userID;
            });

            // Deleted
            //var deleted = ChangeTracker.Entries().Where(v => v.State == EntityState.Deleted &&
            //typeof(IBaseEntity).IsAssignableFrom(v.Entity.GetType())).ToList();

            var deleted = ChangeTracker.Entries().Where(v => v.State == EntityState.Deleted).ToList();

            deleted.ForEach(entry =>
            {
                ((IBaseEntity)entry.Entity).DateDeleted = DateTime.UtcNow;
                ((IBaseEntity)entry.Entity).DeletedBy = _userID;
            });

            foreach (var entry in ChangeTracker.Entries()
                                    .Where(e => e.State == EntityState.Deleted &&
                                    e.Metadata.GetProperties().Any(x => x.Name == "IsDeleted")))
            {
                switch (entry.State)
                {
                    case EntityState.Added:
                        entry.CurrentValues["IsDeleted"] = false;
                        break;

                    case EntityState.Deleted:
                        entry.State = EntityState.Modified;
                        entry.CurrentValues["IsDeleted"] = true;
                        break;
                }
            }
        }
    }



}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using AthlosifyWebArchery.Data;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using AthlosifyWebArchery.Models;
using DinkToPdf.Contracts;
using DinkToPdf;

namespace AthlosifyWebArchery
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            //services.AddHttpContextAccessor();

            services.AddSingleton<IHttpContextAccessor, HttpContextAccessor>();
            services.AddSingleton(typeof(IConverter), new SynchronizedConverter(new PdfTools()));

            services.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));

            // Extended Application User from IdentityUser 
            // and ApplicationRole from IdentityRole

            services.AddIdentity<ApplicationUser, ApplicationRole>(
                options => options.Stores.MaxLengthForKeys = 128)
                .AddEntityFrameworkStores<ApplicationDbContext>()
                .AddDefaultUI()
                .AddDefaultTokenProviders();

            services.AddMvc()
                .AddRazorPagesOptions(options =>
                {
                    options.Conventions.AuthorizeFolder("/Tournaments");
                    options.Conventions.AuthorizeFolder("/TournamentAtheletes");
                    options.Conventions.AuthorizeFolder("/TournamentBatches");
                    options.Conventions.AuthorizeFolder("/TournamentContingents");
                    options.Conventions.AuthorizeFolder("/Admin");
                    //options.Conventions.AuthorizeFolder("/Private");
                    //options.Conventions.AllowAnonymousToPage("/Private/PublicPage");
                    //options.Conventions.AllowAnonymousToFolder("/Private/PublicPages");
                })
                .SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
                                ApplicationDbContext context,
                                RoleManager<ApplicationRole> roleManager,
                                UserManager<ApplicationUser> userManager)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseAuthentication();

            app.UseMvc();

            //UserManagerInitialData.Initialize(context, userManager, roleManager).Wait();

        }


    }
}

使用系统；
使用System.Collections.Generic；
使用系统文本；
使用Microsoft.AspNetCore.Identity.EntityFrameworkCore；
使用Microsoft.EntityFrameworkCore；
使用AthlosifyWebArchery.模型；
使用System.Linq；
使用系统线程；
使用System.Threading.Tasks；
使用System.Linq.Expressions；
使用Microsoft.AspNetCore.Http；
使用Microsoft.AspNetCore.Identity；
命名空间AthlosifyWebArchery.Data
{
公共类ApplicationDbContext:IdentityDbContext
{
私有只读字符串_userID；
私有只读字符串\u用户名；
公共应用程序DBContext（DbContextOptions选项，
IHttpContextAccessor httpContextAccessor
)
：基本（选项）
{
_userName=httpContextAccessor.HttpContext.User.Identity.Name；
//_userID=userManager.GetUserId（httpContext.httpContext.User）；
}
公共数据库集TournamentBatchItem{get；set；}
公共DbSet TournamentBatch{get；set；}
公共虚拟数据库集主机{get；set；}
公共DbSet主机应用程序用户{get；set；}
模型创建时受保护的覆盖无效（ModelBuilder）
{
基于模型创建（生成器）；
foreach（builder.Model.GetEntityTypes（）中的var entityType）
{
//1.添加IsDeleted属性
GetOrAddProperty（“IsDeleted”，typeof（bool））；
//2.创建查询筛选器
var parameter=Expression.parameter（entityType.ClrType）；
//EF.财产（后，“已删除”）
var propertyMethodInfo=typeof（EF）.GetMethod（“Property”）.MakeGenericMethod（typeof（bool））；
var isDeletedProperty=Expression.Call（propertyMethodInfo，参数，Expression.Constant（“IsDeleted”）；
//EF.Property（post，“IsDeleted”）==false
BinaryExpression compareExpression=Expression.MakeBinary（ExpressionType.Equal，isDeletedProperty，Expression.Constant（false））；
//post=>EF.Property（post，“IsDeleted”）==false
var lambda=Expression.lambda（比较表达式，参数）；
实体（entityType.ClrType）.HasQueryFilter（lambda）；
}
//多对多关系
builder.Entity（）
.HasKey（bc=>new{bc.HostID，bc.Id}）；
builder.Entity（）
.HasOne（bc=>bc.Host）
.WithMany（b=>b.HostApplicationUsers）
.HasForeignKey（bc=>bc.HostID）；
builder.Entity（）
.HasOne（bc=>bc.ApplicationUser）
.WithMany（c=>c.HostApplicationUsers）
.HasForeignKey（bc=>bc.Id）；
}
公共覆盖int SaveChanges（bool acceptAllChangesOnSuccess）
{
onbeforecaving（）；
返回base.SaveChanges（AcceptalChangesOnSuccess）；
}
public override Task savechangesync（bool acceptillchangesonsuccess，CancellationToken CancellationToken=default（CancellationToken））
{
onbeforecaving（）；
return base.saveChangesSync（acceptAllChangesOnSuccess，cancellationToken）；
}
保存之前的私有void（）
{
//增加
var added=ChangeTracker.Entries（）。其中（v=>v.State==EntityState.added&&typeof（IBaseEntity）.IsAssignableFrom（v.Entity.GetType（））.ToList（）；
添加了.ForEach（条目=>
{
（（IBaseEntity）entry.Entity）.DateCreated=DateTime.UtcNow；
（（IBaseEntity）entry.Entity）.CreatedBy=\u userID；
（（IBaseEntity）entry.Entity）.LastDateModified=DateTime.UtcNow；
（（IBaseEntity）entry.Entity）.LastModifiedBy=\u userID；
});
//修改
var modified=ChangeTracker.Entries（）。其中（v=>v.State==EntityState.modified&&
typeof（IBaseEntity）.IsAssignableFrom（v.Entity.GetType（））.ToList（）；
modified.ForEach（条目=>
{
（（IBaseEntity）entry.Entity）.LastDateModified=DateTime.UtcNow；
（（IBaseEntity）entry.Entity）.LastModifiedBy=\u userID；
});
//删除
//var deleted=ChangeTracker.Entries（）。其中（v=>v.State==EntityState.deleted&&
//typeof（IBaseEntity）.IsAssignableFrom（v.Entity.GetType（））.ToList（）；
var deleted=ChangeTracker.Entries（）；
已删除。ForEach（条目=>
{
（（IBaseEntity）entry.Entity）.DateDeleted=DateTime.UtcNow；
（（IBaseEntity）entry.Entity）.DeletedBy=\u userID；
});
foreach（ChangeTracker.Entries（）中的var条目）
.Where（e=>e.State==EntityState.Deleted&&
e、 Metadata.GetProperties（）.Any（x=>x.Name==“IsDeleted”））
{
开关（进入状态）
{
案例实体状态。添加：
entry.CurrentValues[“IsDeleted”]=false；
打破
案例实体状态。已删除：
entry.State=实体