private void btnLogin_Click(object sender, EventArgs e)
        {
            if (!this._IsEmailValid(tbIndexLoginEmail) || !this._IsIndexLoginPasswordValid())
            {
                this._CheckIndexLoginEmailValidation();
                this._CheckIndexLoginPasswordValidation();

                return;
            }

            // Start Database Login process
            string email    = tbIndexLoginEmail.Text.Trim();
            string password = tbIndexLoginPassword.Text.Trim();
            string type     = gbIndexLoginUserType.Controls.OfType <RadioButton>().FirstOrDefault(rb => rb.Checked).Text.Trim();

            dynamic user = null;

            if (type.Equals("Student"))
            {
                user = new Tenant();
            }
            else if (type.Equals("Renter"))
            {
                user = new Renter();
            }
            else if (type.Equals("Admin"))
            {
                user = new Admin();
            }

            user.Email    = email;
            user.Password = password;

            user = IndexController.AuthenticateUser(user, this);

            this._ResetIndexLoginInputs();

            if (user == null)
            {
                // Displays the MessageBox.
                MessageBox.Show(
                    "Login Credential is not correct",
                    "Error Login",
                    MessageBoxButtons.OK,
                    MessageBoxIcon.Information
                    );
            }
        }