How to Efficiently Retrieve All Users and Their Associated Roles in .NET Core 2.1 Identity?-Mysql Tutorial-php.cn

How to Efficiently Retrieve All Users and Their Associated Roles in .NET Core 2.1 Identity?

Mary-Kate Olsen

Release： 2024-12-02 07:29:10

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How to Efficiently Retrieve All Users and Their Associated Roles in .NET Core 2.1 Identity?

How to Retrieve All Users with Associated Roles in .NET Core 2.1 Identity

Performing database operations involving user management can be complex, as exemplified by the difficulty encountered in retrieving all Identity users with their associated roles.

Issue: Relationship Access Error

As described in the provided context, an error occurs when attempting to access the Roles property of each IdentityUser. This error is caused by changes to the IdentityUser entity in .NET Core. In earlier versions, IdentityUser used to have a Roles property, but this is no longer the case.

Solution: Implementing Custom Entities

To overcome this issue, one must create custom entities to represent the user-role relationship.

ApplicationUser:

public class ApplicationUser : IdentityUser
{
    public ICollection<ApplicationUserRole> UserRoles { get; set; }
}

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ApplicationUserRole:

public class ApplicationUserRole : IdentityUserRole<string>
{
    public virtual ApplicationUser User { get; set; }
    public virtual ApplicationRole Role { get; set; }
}

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ApplicationRole:

public class ApplicationRole : IdentityRole
{
    public ICollection<ApplicationUserRole> UserRoles { get; set; }
}

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DbContext Update:

public class ApplicationDbContext
    : IdentityDbContext<ApplicationUser, ApplicationRole, string, IdentityUserClaim<string>,
    ApplicationUserRole, IdentityUserLogin<string>,
    IdentityRoleClaim<string>, IdentityUserToken<string>>
{
    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        builder.Entity<ApplicationUserRole>(userRole =>
        {
            userRole.HasKey(ur => new { ur.UserId, ur.RoleId });

            userRole.HasOne(ur => ur.Role)
                .WithMany(r => r.UserRoles)
                .HasForeignKey(ur => ur.RoleId)
                .IsRequired();

            userRole.HasOne(ur => ur.User)
                .WithMany(r => r.UserRoles)
                .HasForeignKey(ur => ur.UserId)
                .IsRequired();
        });
    }
}

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Startup Modification:

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

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Data Retrieval:

Eagerly load the user roles and roles:

this.Users = userManager.Users.Include(u => u.UserRoles).ThenInclude(ur => ur.Role).ToList();

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By implementing these custom entities and updating the database context, you can retrieve all users and their associated roles in .NET Core 2.1 Identity.

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