无法从 'method group' 转换为 asp mvc 身份中的 'Func<ApplicationRoleManager>

Question

此代码用于在数据库中创建角色。

身份配置：

public class ApplicationRoleManager : RoleManager<IdentityRole>
{
    public ApplicationRoleManager(RoleStore<IdentityRole> roleStore)
        : base(roleStore)
    {
    }

    public static ApplicationRoleManager Create(IOwinContext context)
    {
        var roleStore = new RoleStore<IdentityRole>(context.Get<ApplicationDbContext>());
        return new ApplicationRoleManager(roleStore);
    }
}

但在 Startup.Auth 中显示错误：

如何解决这个错误？

编辑

public void Configuration(IAppBuilder app)
{
    ConfigureAuth(app);
}

Answer 1

CreatePerOwingContext<T> 的签名如下所示：

public static IAppBuilder CreatePerOwinContext<T>(this IAppBuilder app, Func<IdentityFactoryOptions<T>, IOwinContext, T> createCallback) where T : class, IDisposable

或者像这样：

public static IAppBuilder CreatePerOwinContext<T>(this IAppBuilder app, Func<T> createCallback) where T : class, IDisposable

即你以太需要提供一个函数来为你创建一个对象，即

app.CreatePerOwinContext<ApplicationRoleManager>(() => new ApplicationRoleManager(/*blah params*/));

这将使用第二个覆盖。或返回默认值：

public static ApplicationRoleManager Create(IdentityFactoryOptions<ApplicationRoleManager> options, IOwinContext context)
{
    var applicationDbContext = context.Get<ApplicationDbContext>();
    var roleStore = new RoleStore<IdentityRole>(applicationDbContext);
    var manager = new ApplicationRoleManager(roleStore);

    return manager;
}