ASP.NET Membership: Where is Current User ID Stored?

问题

Using ASP.NET membership, if I want to get information for the current user, I can call MembershipUser.GetUser()

So, somehow the system must know the ID of the current user.

If this is correct, and all I want is the ID of the current user, is there a way to get it without returning all the user information from the database?

I know I can get the username of the current user using User.Identity.Name, but I need the ID.

回答1:

The short answer is no you can't get only userID without retrieve whole user info when you use built-in membership provider, only by this

    MembershipUser user = Membership.GetUser();
    string UserID = user.ProviderUserKey.ToString();

But if you want to have method or property which retrieve only userID, you must re-implement your own membership provider or(it's simply) to implement IPrincipal interface

回答2:

To return the UserId, use the command bellow in your controller:

User.Identity.GetUserId();

To return the UserName, use:

User.Identity.Name;

To return the user:

var user = db.Users.Find(User.Identity.GetUserId());

Please refer to the post: How to get current user, and how to use User class in MVC5?

回答3:

As you've guessed, the Membership API doesn't support what you want out of the box. In the past, I've used a helper class instead of creating my own provider. In this case it's pretty simple, maybe something like this:

public static object GetUserId() {
  return GetUserId(HttpContext.Current.User.Identity.Name, true);
}    
public static object GetUserId(string userName) {
  return GetUserId(userName, true);
}
public static object GetUserId(string userName, bool UpdateLastActivity) {
  using (SqlConnection c = new SqlConnection(CONNECTION_STRING)) {
    string sql = @"
DECLARE @UserId uniqueidentifier
SELECT @UserId=u.UserId
FROM dbo.aspnet_Applications AS a
  ,dbo.aspnet_Users AS u
  ,dbo.aspnet_Membership AS m
WHERE
  a.LoweredApplicationName=LOWER(@ApplicationName)
  AND u.ApplicationId=a.ApplicationId
  AND u.LoweredUserName=LOWER(@UserName)
  AND u.UserId=m.UserId;
IF @UserId IS NOT NULL AND @UpdateLastActivity=1
  UPDATE dbo.aspnet_Users
  SET LastActivityDate=@CurrentTimeUtc
  WHERE UserId=@UserId;
SELECT @UserId  
      ";
    using (SqlCommand cmd = new SqlCommand(sql, c)) {
      cmd.Parameters.AddWithValue("@ApplicationName", Roles.ApplicationName);
      cmd.Parameters.AddWithValue("@UserName", userName);
      cmd.Parameters.AddWithValue("@UpdateLastActivity", UpdateLastActivity);
      cmd.Parameters.AddWithValue("@CurrentTimeUtc", DateTime.UtcNow);
      object id = null;
      c.Open();
      id = cmd.ExecuteScalar();
      return id != DBNull.Value ? id : null;
    }
  }
}

Above is pretty similar to what's done in the Membership API when calling GetUser()

回答4:

You can use MembershipUser.UserName to get the user id or try calling Membership.GetUser(User.Identity.Name) and see if that works for you.

回答5:

After looking into this further, it seems that the ASP.NET Membership API does not track the user ID after all. It must track just the user name (User.Identity.Name). The ID is not required because Membership.GetUser() can find a user from an ID or user name.

In fact, Membership.GetUser() must simply translate to Membership.GetUser(User.Identity.Name). Since it can obtain the current user from the user name, there is no longer any reason to assume that the current user ID is cached anywhere.

So it appears the ID is not loaded into memory, and the only way to obtain the ID is to load the data from the database (which means loading the entire user record when using the ASP.NET Membership API).

回答6:

Consider

int userId = WebSecurity.CurrentUserId;

Credit: https://stackoverflow.com/a/15382691/1268910

来源：https://stackoverflow.com/questions/8860224/asp-net-membership-where-is-current-user-id-stored

标签

ASP.NET

asp.net-membership