private void button1_Click(object sender, EventArgs e)
        {
            checking c = new checking("n");

            c.Show();
            this.Hide();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            if (string.IsNullOrEmpty(this.textBox1.Text))
            {
                MessageBox.Show("enter Password!!");
            }
            else
            {
                // authenticating login

                string userName = (String)comboBox1.SelectedItem;
                try
                { //you need to add your server name to connect on your computer
                    String        conString = "server=DESKTOP-C7FFPE6\\MSSQLSERVER01; database=patientMoniter; Integrated Security=SSPI;";
                    String        Query     = "select * from loginUser where userName='******'";
                    SqlConnection connect   = new SqlConnection(conString);
                    SqlCommand    command   = new SqlCommand(Query, connect);
                    SqlDataReader reader;

                    connect.Open();
                    reader = command.ExecuteReader();

                    string password = "";
                    while (reader.Read())
                    {
                        password = (string)reader["password"];
                    }
                    String eneteredPassword = textBox1.Text;
                    if (eneteredPassword == password)
                    {
                        checking c = new checking(userName);
                        c.Show();
                        this.Hide();
                    }
                    else
                    {
                        MessageBox.Show("Wrong Password");
                    }

                    connect.Close();
                }
                catch (Exception ex)
                {
                    MessageBox.Show(ex.Message);
                }
            }
        }