ขอตัวอย่าง Code Check Password / Confirm Password

private void changepassword()
        {
            if ((txtoldpwd.Text == "") || (txtnewpwd.Text == ""))
            {
                MessageBox.Show("กรุณากรอกข้อมูลให้ครบ", "Check", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            }

            else
            {
                string ConnStr = Properties.Settings.Default.DatabaseCarserviceConnectionString;
                using (OleDbConnection conn = new OleDbConnection(ConnStr))
                {
                    string sql = "UPDATE [Employee] set Emp_User='" + txtusername.Text + "',";                   
                    sql += "Emp_Password='" + txtconfirm.Text + "' ";
                    sql += "WHERE Emp_ID='" + txtCusID.Text + "' ";
                    conn.Open();
                    using (OleDbCommand cmd = new OleDbCommand(sql, conn))
                    {
                        cmd.ExecuteNonQuery();
                    };
                    string strCmd = "SELECT * FROM Employee ORDER BY Emp_ID";
                    OleDbDataAdapter da = new OleDbDataAdapter(strCmd, conn);
                    DataSet ds = new DataSet();
                    da.Fill(ds);
                };
            }
        }

private void btnsave_Click(object sender, EventArgs e)
        {            
            if (txtnewpwd != txtconfirm)
            {
                MessageBox.Show("Password ไม่ตรงกัน กรุณากรอกใหม่", "Check", MessageBoxButtons.OK, MessageBoxIcon.Asterisk);
            }           
            else
            {
                changepassword();
                InPassCorrect();
            }            
        }