Object Storing and Utilization on another script.

Thank you got the reply, but 'u' isn't null, it's filled in the 'Login.cs'

Here I'll show you what I mean.

There are 3 scripts here, User.cs, Login.cs and MainMenu.cs

A reply would be much appreciated, I've been trying to figure this out for 3 hours now :(

--------------------------------------User.cs--------------------------------------------
namespace OfficeNotes
{
public class User
{
//----------------------------------------------------------------------------------------
//Username string
private string _username;
public string Username
{
get { return _username; }
set { _username = value; }
}

//Pin String
private string _pin;
public string Pin
{
get { return _pin; }
set { _pin = value; }
}

//UserID String
private int _userID;
public int UserID
{
get { return _userID; }
set { _userID = value; }
}

//UserFirstname String
private string _userfirstname;
public string User_First_Name
{
get { return _userfirstname; }
set { _userfirstname = value; }
}

//UserLastName String
private string _userlastname;
public string User_Last_Name
{
get { return _userlastname; }
set { _userlastname = value; }
}

//UserRoom String
private string _userroom;
public string User_Room
{
get { return _userroom; }
set { _userroom = value; }
}

//--------------------------------------------------------------------------------

//Connects to SQL database
private SqlConnection connect;

//Constructor of "Login" also connection to the SQL database and storing details in "constring".
public User()
{
string constring = "Data Source=OLLY-PC\\SQLEXPRESS;Initial Catalog=OfficeNotes;User ID=OfficeNotes;Password=222;";
ConnectToDatabase(constring);
}

public void ConnectToDatabase(string info)
{
connect = new SqlConnection(info);
connect.Open();
}

public bool FillObject(string inPIN, string inUser){

//Filling "sql" inPin & inUser with key's from FillObject
string sql = "SELECT UserID, Username, Pin, FirstName, LastName, Room FROM NotesUser WHERE Pin = '" + inPIN + "' AND Username = '" + inUser +"'";

//Executing the application on the database
SqlCommand sqlcommand = new SqlCommand(sql,connect);
SqlDataReader sr = sqlcommand.ExecuteReader();

//Fills strings with values from database if datareader reads, the process = strings sql > sqlcommand > sr > DATA
if(sr.Read())
{
this.UserID = sr.GetSqlInt32(0).Value;
this.Username = sr.GetSqlString(1).Value;
this.Pin = sr.GetSqlString(2).Value;
this.User_First_Name = sr.GetSqlString(3).Value;
this.User_Last_Name = sr.GetSqlString(4).Value;
this.User_Room = sr.GetSqlString(5).Value;
return true;
}
return false;
}

public int FindIDByName(string name)
{
return 0;
}

public class UserStore
{
UserStore ustore = new UserStore();
ustore.Logged = u;
}
}
}

--------------------------------------Login.cs--------------------------------------------
namespace OfficeNotes
{
public partial class Login : Template
{
public Login()
{
InitializeComponent();
}

//once the "Go" button is clicked the following method is attepmted.
public void btn_login(object sender, EventArgs e)
{
string username = txtusername.Text;
string pin = txtPin.Text;

//creating the object user, u
User u = new User();

bool success = u.FillObject(pin, username);

//Going onto next form, MainMenu
if (success == true)
{
MainMenu main = new MainMenu();
main.LoggedUser = u;
main.Show();

Login log = new Login();
log.Close();
}

//Alert the user that there is no user under the current login.
else
{
alert_box.DrawnText = "No user";
}
}
}
}

--------------------------------------MainMenu.cs--------------------------------------------
namespace OfficeNotes
{
public partial class MainMenu : Form
{

private User _loggedUser; // variable

public User LoggedUser // encapsulating property
{
get { return _loggedUser; }
set { _loggedUser = value; }
}

public MainMenu()
{
InitializeComponent();

//Date and Date
textbar_time_date.DrawnText = DateTime.Now.ToString("hh:mmtt : dd/MMMM/yyyy");

//Display first/last name and room number from object user
name_room.DrawnText = LoggedUser.Username;
}

}
}

public MainMenu() { InitializeComponent(); //Date and Date textbar_time_date.DrawnText = DateTime.Now.ToString("hh:mmtt : dd/MMMM/yyyy"); //Display first/last name and room number from object user name_room.DrawnText = [COLOR="red"][B]LoggedUser.Username;[/B][/COLOR] }