ASP.NET Core 2.0 MVC自定义数据库初始化程序类上的ObjectDisposedException

问题描述

限时删除！！

自定义数据库初始化类中出现以下异常:

I'm getting the following exception in my custom database initializer class:

这是初始化器:

public class DbInitializer : IDbInitializer
{
    private readonly ApplicationDbContext _Context;
    private readonly UserManager<ApplicationUser> _userManager;
    private readonly RoleManager<ApplicationRole> _roleManager;

    public DbInitializer(
        ApplicationDbContext context,
        UserManager<ApplicationUser> userManager,
        RoleManager<ApplicationRole> roleManager)
    {
        _context = context;
        _userManager = userManager;
        _roleManager = roleManager;
    }

    public async void Initialize()
    {
        var adminUsers = _userManager.GetUsersInRoleAsync(RoleClaimValues.Admin).Result;
        if (adminUsers == null || adminUsers.Count == 0)
        {
(...)
        }
     }
}

public interface IDbInitializer
{
    void Initialize();
}

这是startup.cs，在其中我在ConfigureService中添加IDbInitializer的范围，然后从Configure调用它:

And here is the startup.cs where i add the scope of IDbInitializer in ConfigureService and then call it from Configure:

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

    public IConfiguration Configuration { get; }


    public void ConfigureServices(IServiceCollection services)
    {
        // Add framework services.
        services.AddDbContext<ApplicationDbContext>(options =>
            options.UseSqlServer(Configuration.GetConnectionString("ApplicationConnection")));

        services.AddIdentity<ApplicationUser, ApplicationRole>(o => {
            o.Password.RequireDigit = false;
            o.Password.RequiredLength = 4;
            o.Password.RequireLowercase = false;
            o.Password.RequireUppercase = false;
            o.Password.RequireNonAlphanumeric = false;
            o.User.RequireUniqueEmail = true;
        })
            .AddEntityFrameworkStores<ApplicationDbContext>()
            .AddDefaultTokenProviders();

        services.AddMvc();

        // Add application services.
        services.AddTransient<IEmailSender, MessageServices>();
        //Seed database
        services.AddScoped<IDbInitializer, DbInitializer>();
    }

    public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory, IDbInitializer dbInitializer)
    {
        loggerFactory.AddConsole();

        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();

            app.UseBrowserLink();
            app.UseDatabaseErrorPage();

            app.UseStatusCodePages("text/plain", "Status code page, status code: {0}");
        }
        else
        {
            app.UseExceptionHandler("/Error");
        }

        app.UseStaticFiles();
        app.UseAuthentication();

        dbInitializer.Initialize();

        app.UseMvc(routes =>
        {
            routes.MapRoute(
                name: "default",
                template: "{controller=Home}/{action=Index}/{id?}");
        });
    }
}

我不知道为什么异常告诉我们问题可能出在上下文放置在某个地方.

I don't know why the exception tells that the problem could be that the context is disposed somewhere.

我还添加了

.UseDefaultServiceProvider(options =>
  options.ValidateScopes = false)

在.UseStartup<Startup>()之后，以防万一与范围有关，但例外是相同的.

after .UseStartup<Startup>() just in case it was something relative to the scopes, but the exception is the same.

推荐答案

我遇到了与您相同的问题.您确实必须更改所有代码才能返回Task.否则，DbContext将在所有操作完成之前被处理掉.

I had the same problem as you had.You indeed have to change all code to return a Task. Otherwise the DbContext is disposed before all actions are done.

数据库初始化在dotnet core 2.0中进行了更改.我创建了有关此特定主题的博客.参见 http://www.locktar.nl/programming/net-core/seed-database-users-roles-dotnet-core-2-0-ef/了解更多信息.

Database Initialization is changed in dotnet core 2.0. I created a blog about this specific topic.See http://www.locktar.nl/programming/net-core/seed-database-users-roles-dotnet-core-2-0-ef/ for more information.

这篇关于ASP.NET Core 2.0 MVC自定义数据库初始化程序类上的ObjectDisposedException的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！

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