How to update user details using ASP. NET Core MVC? ConcurrencyFailure

Question

I am trying to update user details from a SQL database using ASP.NET Core MVC and Angular. I want to update the user without sending the UserID to the API so i have to get the UserId in the PUT method. I used Entity and Identity to create the database.

With the following code I am getting this error:

Code: "ConcurrencyFailure"
Description: "Optimistic concurrency failure, object has been modified."

How can i make this works?

PUT Method

[HttpPut]
        [Route("Update")]
        //api/ApplicationUser/Update

        public async Task<Object> PutApplicationUser(UserAccountModel model)
        {
            var user = _userManager.GetUserId(HttpContext.User);
            
            var applicationUser = new UserAccount()
            {
                UserName = model.UserName,
                FirstName = model.FirstName,
                LastName = model.LastName,
                Email = model.Email,
                PhoneNumber = model.PhoneNumber,
                VerificationCode = "",
                ExpCode = new DateTime(2020, 8, 18),
                SecurityStamp = Guid.NewGuid().ToString()
               
            };

            try
            {
                var result = await _userManager.UpdateAsync(applicationUser);
                
                return result;

            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

UserAccount model

    public class UserAccount : IdentityUser
    {
        [Column(TypeName = "nvarchar(30)")]
        public string FirstName { get; set; }

        [Column(TypeName = "nvarchar(30)")]
        public string LastName { get; set; }

        [Column(TypeName = "nvarchar(30)")]
        public string VerificationCode { get; set; }

        [Column(TypeName = "smalldatetime")]
        public DateTime ExpCode { get; set; }

        public virtual ICollection<File> File { get; set; }

        public virtual ICollection<Folder> Folder { get; set; }
    }

Answer 1

Try getting ConcurrencyStamp for this user and set it to your update model:

        var user = _userManager.GetUserId(HttpContext.User);
        var currStamp = ... // somehow get current stamp
        var applicationUser = new UserAccount()
        {
            ...
            ConcurrencyStamp = currStamp 
        };

Or just use UserManager<TUser>.GetUserAsync and update fields on returned user:

var user = await _userManager.GetUserAsync(HttpContext.User);
user.UserName = model.UserName;
.....
var result = await _userManager.UpdateAsync(user);

Answer 2

I think you should update the record that exist. This works:

string user = User.Claims.First(c => c.Type == "UserID").Value; 
var userModel = await _userManager.FindByIdAsync(user);
userModel.model.UserName;
userModel.FirstName = model.FirstName;
userModel.LastName = model.LastName;
userModel.Email = model.Email;
userModel.PhoneNumber = model.PhoneNumber;
userModel.VerificationCode = "";
userModel.ExpCode = new DateTime(2020, 8, 18);