当我添加新用户并尝试在下一行添加声明时，我在正文中引用了错误

Question

System.InvalidOperationException：实体类型“AppUser”上的“ConcurrencyStamp”属性是键的一部分，因此不能修改或标记为已修改。要使用标识外键更改现有实体的主体，首先删除依赖项并调用“SaveChanges”，然后将依赖项与新主体关联。'

一个简单的代码如下，

1. 我正在创建一个新用户。
2. 对于同一用户，我尝试添加声明。

3. 我已经从 asp.net core(3.1.2) 添加了 IdentityUser 类

       var user = new AppUser() { UserName = userName, Email = emailAddress, FirstName = firstName, LastName = lastName };
       var passcode = GeneratePassword();
       var newUser = await userManager.CreateAsync(user, passcode);
   
       var addedClaim = await userManager.AddClaimAsync(user, new System.Security.Claims.Claim("usertype", "admin"));
   
       internal class AppUser : IdentityUser<int>, IRecord, IMPrimary {
        [DatabaseGenerated(DatabaseGeneratedOption.Identity)]   
        [Column("RecordCode")] 
        public Guid RecId { get; set; } 
        public override int Id { get; set; } 
        public string FirstName { get; set; } 
        public string LastName { get; set; } 
       } 
   
       (below is coming from vb.net coded class)
   
       Public Interface Record 
       Property RecId As Guid 
       End Interface 
       Public Interface IMPrimary 
       Property Id As Integer 
       End Interface 
   

Asp.net 核心中的IdentityUser

public class IdentityUser<TKey> where TKey : IEquatable<TKey>
    {
        //
        // Summary:
        //     Initializes a new instance of Microsoft.AspNetCore.Identity.IdentityUser`1.
        public IdentityUser();
        //
        // Summary:
        //     Initializes a new instance of Microsoft.AspNetCore.Identity.IdentityUser`1.
        //
        // Parameters:
        //   userName:
        //     The user name.
        public IdentityUser(string userName);

        //
        // Summary:
        //     Gets or sets the date and time, in UTC, when any user lockout ends.
        //
        // Remarks:
        //     A value in the past means the user is not locked out.
        public virtual DateTimeOffset? LockoutEnd { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if two factor authentication is enabled for this
        //     user.
        [PersonalData]
        public virtual bool TwoFactorEnabled { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if a user has confirmed their telephone address.
        [PersonalData]
        public virtual bool PhoneNumberConfirmed { get; set; }
        //
        // Summary:
        //     Gets or sets a telephone number for the user.
        [ProtectedPersonalData]
        public virtual string PhoneNumber { get; set; }
        //
        // Summary:
        //     A random value that must change whenever a user is persisted to the store
        **public virtual string ConcurrencyStamp { get; set; }**
        //
        // Summary:
        //     A random value that must change whenever a users credentials change (password
        //     changed, login removed)
        public virtual string SecurityStamp { get; set; }
        //
        // Summary:
        //     Gets or sets a salted and hashed representation of the password for this user.
        public virtual string PasswordHash { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if a user has confirmed their email address.
        [PersonalData]
        public virtual bool EmailConfirmed { get; set; }
        //
        // Summary:
        //     Gets or sets the normalized email address for this user.
        public virtual string NormalizedEmail { get; set; }
        //
        // Summary:
        //     Gets or sets the email address for this user.
        [ProtectedPersonalData]
        public virtual string Email { get; set; }
        //
        // Summary:
        //     Gets or sets the normalized user name for this user.
        public virtual string NormalizedUserName { get; set; }
        //
        // Summary:
        //     Gets or sets the user name for this user.
        [ProtectedPersonalData]
        public virtual string UserName { get; set; }
        //
        // Summary:
        //     Gets or sets the primary key for this user.
        [PersonalData]
        public virtual TKey Id { get; set; }
        //
        // Summary:
        //     Gets or sets a flag indicating if the user could be locked out.
        public virtual bool LockoutEnabled { get; set; }
        //
        // Summary:
        //     Gets or sets the number of failed login attempts for the current user.
        public virtual int AccessFailedCount { get; set; }

        //
        // Summary:
        //     Returns the username for this user.
        public override string ToString();
    }

Answer 1

我找到了错误的原因，所以我想与大家分享。我有一个重写的 OnModelCreating 方法。我主要用它来设置字符串值列的最大字符长度。对于某些内部目的逻辑，我将键设置为这些字符串基列。因此，当涉及到 IdentityUser 列时，它们也在无意中通过同一管道。下面代码中的 p.DeclaringEntityType.AddKey(p); 正在向 ConcurrencyStamp 添加密钥，这也是 Identity System 从未预料到的，因此它抛出了异常。

感谢Gert Arnold 为我提供的帮助。

protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            if (modelBuilder == null)
                throw new NoNullAllowedException();
            var conventions = GetDbConventions();
            var props = GetPropertiesOfType(typeof(string));
            int maxCharacterLength = conventions.StringsColumnLength;
            foreach (var p in props)
            {
                if (p.GetMaxLength() < maxCharacterLength)
                    p.SetMaxLength(maxCharacterLength);
                p.IsNullable = false;
                p.DeclaringEntityType.AddKey(p);
            };  
       }