如何在EF Core中通过连接两个表来获得两个不同的用户名？

// 定义User实体类
public class User
{
    public int UserId { get; set; }
    public string UserName { get; set; }
    // 导航属性，表示一个用户拥有多个角色
    public ICollection<Role> Roles { get; set; }
}

// 定义Role实体类
public class Role
{
    public int RoleId { get; set; }
    public string RoleName { get; set; }
    // 导航属性，表示一个角色属于多个用户
    public ICollection<User> Users { get; set; }
}

// 在DbContext中配置表之间的关联关系
public class YourDbContext : DbContext
{
    public DbSet<User> Users { get; set; }
    public DbSet<Role> Roles { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .HasMany(u => u.Roles)
            .WithMany(r => r.Users)
            .UsingEntity<Dictionary<string, object>>(
                "UserRoles",
                u => u.HasOne<Role>().WithMany().HasForeignKey("RoleId"),
                r => r.HasOne<User>().WithMany().HasForeignKey("UserId"),
                j =>
                {
                    j.HasKey("UserId", "RoleId");
                    j.ToTable("UserRoles");
                });
    }
}

using (var context = new YourDbContext())
{
    var query = from user in context.Users
                join userRole in context.UserRoles on user.UserId equals userRole.UserId
                join role in context.Roles on userRole.RoleId equals role.RoleId
                select new
                {
                    UserName = user.UserName,
                    RoleName = role.RoleName
                };

    foreach (var result in query)
    {
        Console.WriteLine($"User Name: {result.UserName}, Role Name: {result.RoleName}");
    }
}