How do I access the logged in user from a sharepoint webpart?

Question

I have a Sharepoint site that uses Forms Based Authentication. I would like to discover the last password updated date and the creation, for the purpose of discovering whether they have changed their password since the account was created. I found a question on here already that seems to explain how to do this, but the code is not working for me. Here is a link to that question:

How to force change password on first login for FBA user?

The problem is, I am encountering the same error that the original poster encountered, I am getting an exception "The method or operation is not implemented." on this line: System.Web.Security.MembershipUser user = System.Web.Security.Membership.GetUser(currentUser.LoginName)

Below the original post is another post seeming to indicate how he solved the issue, I tried wrapping my code in that but it still throws the same error. Below is a complete listing of the code for my non visual webpart, can you help me find out how to get the userinfo for the logged in user? I will also accept as an answer, a way to get the userid of the currently logged in user, because with that I can query the database directly to retrieve the information.

I am using Sharepoint2013, VisualStudio2013, and SharePoint 2013 FBA Pack

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.Administration.Claims;

namespace mysharepointproject.CheckPassword
{
    [ToolboxItemAttribute(false)]
    public class CheckPassword : WebPart
    {
        protected override void CreateChildControls()
        {
            Boolean PasswordChangeRequired = false;
            SPUser currentUser = SPContext.Current.Web.CurrentUser;
            if (SPSecurity.AuthenticationMode == System.Web.Configuration.AuthenticationMode.Forms)
            {
                SPClaimProviderManager mgr = SPClaimProviderManager.Local;
                if (mgr != null)
                {
                    SPClaim userLogonNameClaim = mgr.DecodeClaim(SPContext.Current.Web.CurrentUser.LoginName);
                    SPOriginalIssuerType issuerType = SPOriginalIssuers.GetIssuerType(userLogonNameClaim.OriginalIssuer);
                    if (Convert.ToString(issuerType).Equals("Forms"))
                    {
                        SPSecurity.RunWithElevatedPrivileges(delegate()
                        {
                            //The line below fails with The method or operation is not implemented.
                            System.Web.Security.MembershipUser user = System.Web.Security.Membership.GetUser(currentUser.LoginName);
                            if (user != null)
                            {
                                if (user.LastPasswordChangedDate == user.CreationDate)
                                {
                                    PasswordChangeRequired = true;
                                }
                            }
                        });
                    }
                }
            }

            if (PasswordChangeRequired)
            {
                //redirect to the page where users changes their password
                HttpContext.Current.Response.Redirect("~/SitePages/cp.aspx");
            }
        }
    }
}

Answer 1

Here is how I eventually solved the problem:

using System;
using System.ComponentModel;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using System.Data.SqlClient;
using Microsoft.SharePoint.Administration.Claims;
using Microsoft.SharePoint.Utilities;

namespace mysharepointproject.CheckPassword
{
    [ToolboxItemAttribute(false)]
    public class CheckPassword : WebPart
    {
        protected override void CreateChildControls()
        {
            Boolean PasswordChangeRequired = false;
            SPUser currentUser = SPContext.Current.Web.CurrentUser;
            String username = "";
            if (SPSecurity.AuthenticationMode == System.Web.Configuration.AuthenticationMode.Forms)
            {
                SPClaimProviderManager mgr = SPClaimProviderManager.Local;
                if (mgr != null)
                {
                    SPClaim userLogonNameClaim = mgr.DecodeClaim(SPContext.Current.Web.CurrentUser.LoginName);
                    SPOriginalIssuerType issuerType = SPOriginalIssuers.GetIssuerType(userLogonNameClaim.OriginalIssuer);
                    if (Convert.ToString(issuerType).Equals("Forms"))
                    {
                        //i:0#.w|domain\user for windows
                        //i:0#.f|fbamembershipprovider|username for FBA
                        //so we expect there to be 3 elements in the array.  
                        //if there are more than that, the user has added | into his username, so we'll handle that
                        String[] usernameparts = currentUser.LoginName.ToString().Split('|');
                        if (usernameparts.Length > 2)
                        {
                            for (int i = 2; i < usernameparts.Length; i++)
                            {
                                username += usernameparts[i];
                            }
                            username = username.Replace("%7c", "|");
                        }
                        else
                        {
                            username = usernameparts[usernameparts.Length - 1];
                        }
                    }
                } 
            }

            //connect to db, get user, check state
            SqlConnection conn = new SqlConnection();
            conn.ConnectionString = "Data Source = DOMAIN\\SHAREPOINT; Initial Catalog=ASPNETDB; Integrated Security = SSPI";
            conn.Open();

            SqlCommand sql = new SqlCommand();
            SqlDataReader rdr;
            sql.CommandText = "SELECT 1 as needschanging from dbo.aspnet_Membership M " +
            "Join [aspnet_Users] U on M.[UserId] = U.[UserId] " +
            "Where " +
            "M.[LastPasswordChangedDate] <= M.[CreateDate] " +
            "AND " +
            "U.[UserName] = '" + username + "'";

            sql.Connection = conn;
            rdr = sql.ExecuteReader();

            while (rdr.Read())
            {
                if (rdr["needschanging"].ToString() == "1")
                {
                    PasswordChangeRequired = true;
                }
            }

            conn.Close();

            if (PasswordChangeRequired)
            {
                HttpContext.Current.Response.Redirect("~/SitePages/cp.aspx");
            }
        }
    }
}