protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
        {
            if (keyData == (Keys.Control | Keys.V))
            {
                errorProviderLogin.SetError(txtUsername, "Pasting is not allowed");
                MessageBox.Show("Pasting is not allowed...", "CTRL +V",
                    MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                errorProviderLogin.Clear();
                return true;
            }
            else
            return base.ProcessCmdKey(ref msg, keyData);
        }


        private void frmLogin_Load(object sender, EventArgs e)
        {

            txtUsername.Clear();
            txtPassword.Clear();
        }

        private void txtUsername_KeyPress(object sender, KeyPressEventArgs e)
        {
            byte num = Convert.ToByte(e.KeyChar);

            if(num == 13)
            {
                SendKeys.Send("{Tab}");
                e.Handled = true;
            }
            else if((num == 39) || (num == 34) || (num == 59))
            {
                e.Handled = true;
            }

        }

        private void txtPassword_KeyPress(object sender, KeyPressEventArgs e)
        {
            if (e.KeyChar.ToString() == "\r")
            {
                SendKeys.Send("{Tab}");
                e.Handled = true;
            }
        }

        private void btnOkay_Click(object sender, EventArgs e)
        {
            //establish connection
            SqlConnection cn = new SqlConnection();

            if (cn.State == ConnectionState.Closed)
            {
                cn.ConnectionString = "Data Source=" +
                   stcSalesInv.myServer + ";Initial Catalog=" +
                   stcSalesInv.myDataBase + ";Integrated Security=" +
                   stcSalesInv.myIntSec + "; User ID =" + stcSalesInv.myUserID +
                   "; Password =" + stcSalesInv.myPassword + ";";
                cn.Open();
            }
            SqlCommand cmd = new SqlCommand();
            SqlDataReader reader;

            //validate
            if (txtUsername.Text == "")
            {
                MessageBox.Show("Please type your username.");
                txtUsername.Focus();
                return;
            }
            else if (txtPassword.Text == "")
            {
                MessageBox.Show("Please type your password.");
                txtPassword.Focus();
                return;
            }
            //SQL Injection
            if((Regex.IsMatch(txtUsername.Text, "[\'\"\\/*-;{}()]_")== true) ||
                (Regex.IsMatch(txtUsername.Text, "[xp_]")==true ))
            {
                MessageBox.Show("The Username contains characters that may override the system.",
                    "SQL INJECTION", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }
            //check username and password
            try
            {
                cmd.CommandType = CommandType.Text;
                //cmd.CommandText = "SELECT Username, UserLevel " +
                //"FROM Users2 WHERE Username '" + txtUsername.Text + "' AND Password = '" + EncDec.Encrypt(txtPassword.Text, "secret") +
                // "'";

                cmd.Parameters.Add("@username", txtUsername.Text);
                cmd.Parameters.Add("@password", EncDec.Encrypt(txtPassword.Text, "secret"));
                cmd.CommandText = "SELECT Username, UserLevel " +
                    " FROM Users2 WHERE Username = @username " +
                    " AND Password = @password";

                cmd.Connection = cn;
                reader = cmd.ExecuteReader();

                if (reader.HasRows == false)
                {
                    //stcSalesInv.ShowBar = false;

                    MessageBox.Show("Please use valid username and type correct passowrd");
                    return;
                }
                stcSalesInv.ShowBar = true;

                while (reader.Read())
                {
                    stcSalesInv.UserName = reader.GetValue(0).ToString();
                    stcSalesInv.UserLevel = reader.GetValue(1).ToString();
                }

                cn.Close();
                reader.Close();

                this.Hide();

                stcSalesInv.NewMDI.Show();
                stcSalesInv.NewMDI.Focus();
                stcSalesInv.NewMDI.Refresh();

            }
            catch (Exception errMsg)
            {
                MessageBox.Show(errMsg.Message);
            }
        }

        private void btnCancel_Click(object sender, EventArgs e)
        {
            this.Close();
        }

        private void txtUsername_MouseDown(object sender, MouseEventArgs e)
        {
            if(e.Button == MouseButtons.Right)
            {
                errorProviderLogin.SetError(txtUsername, "Right-click is not allowed");
                MessageBox.Show("Right-click is not allowed...", "MOUSE BUTTON",
                    MessageBoxButtons.OK, MessageBoxIcon.Exclamation);
                errorProviderLogin.Clear();
                return;
            }
        }