how to hide a form when you are in a different method

Question

 hi..

I have the following question. How can I hide a form ? when while i'm not in form itself??  I go from my form to my BusinessLocig to my DataAccesLayer. I want to hide the form in the dataAccessLayer because there it checked if the user is logged in. However when I use Login(form name).Hide() it doesn;t hide.

 

here is my code" 

// method on form login
 private void login_button_Click(object sender, EventArgs e)
        {
            var organisationId = Convert.ToInt32(organissationlabel.Text);
            string connectionString;
            Password.Text = Encrypt(Password.Text);
            using (var connection = DatabaseLayer.OpenConnection())
                connectionString = ConnectionstringBusinessLogic.GetConnectionStringByOrgid(connection, null, Convert.ToInt32(organissationlabel.Text));

            using (var connection = DatabaseLayer.OpenSecondConnection(connectionString))
            using (var transaction = connection.BeginTransaction())
            {
                var userAmmountByOrgId = UserBusinessLogic.GetUserAmmountByOrgId(connection, transaction, organisationId);
                var userAmmountContract = UserBusinessLogic.GetAllowedUsersByOrgId(connection, transaction, organisationId);

                if (userAmmountByOrgId >= userAmmountContract)
                    label2.Visible = false;

                UserBusinessLogic.UserLogin(connection, transaction, Username.Text, Password.Text, organisationId, connectionString);
                transaction.Commit();
                Hide(); // hier moet nog naar gekeken worden
            }
        }  public static void UserLogin(SqlConnection connection, SqlTransaction transaction, string username, string password, int organisationId, string connectionString)
       {
           UserDal.UserLogin(connection, transaction, username, password, organisationId, connectionString);
       }

public static  void UserLogin(SqlConnection connection, SqlTransaction transaction, string username, string password, int organisationId, string connectionString)
       {
           if (!username.Equals("") | !password.Equals(""))
           {
               try
               {
                   using (var command = connection.CreateCommand())
                   {
                       command.Transaction = transaction;
                       command.CommandText = "SELECT * FROM Employes WHERE Username=@Username and Password=@Password and OrgId=@OrgId";
                       command.Parameters.Add("@Username", SqlDbType.NVarChar).Value = username;
                       command.Parameters.Add("@Password", SqlDbType.NVarChar).Value = password;
                       command.Parameters.Add("@OrgId", SqlDbType.Int).Value = organisationId;
                       using (var reader = command.ExecuteReader())
                       {
                           if (reader.Read())
                           {
                               MessageBox.Show(Resources.Login_login_button_Click_Login_Successful);;
                               var form = new Form1(connectionString);
                               form.Show();
                               // the hiding should take place here but how ?? login.hide doesn't hide
                           }
                           else
                               MessageBox.Show(Resources.Login_login_button_Click_Invalid_Credentials__Please_Re_Enter);
                       }
                   }
               }
               catch (Exception ex)
               {
                   MessageBox.Show(ex.Message);
               }
           }
       }