For doing password Reset and changing password we always have a thing whether to send the same old password or send a random password to the user.

For generating random password to the user we  will create a code file that will generate random password every-time when the request has been made.

For doing that i have created a class file in my project called as RandomPassword

 public class PasswordGenerator
    {
        public static string GenerateRandomString()
        {
            string ForgotPasswordLength = ConfigurationManager.AppSettings["ForgotPasswordLength"].ToString();
            //It will generate string with combination of small,capital letters and numbers
            char[] charArr = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".ToCharArray();
            string randomString = string.Empty;
            Random objRandom = new Random();
            for (int i = 0; i <=Convert.ToInt32(ForgotPasswordLength) - 1; i++)
            {
                //Don't Allow Repetation of Characters
                int x = objRandom.Next(1, charArr.Length);
                if (!randomString.Contains(charArr.GetValue(x).ToString()))
                {
                    randomString += charArr.GetValue(x);
                }
                else {
                    i -= 1;
                }
            }
            return randomString;
        }

    }

This file will create random password each time we want

To use this file password we will write and mail the random password to the user

   int rowsAffected = 0;
            SqlTransaction transaction = null;
            string randomPassword = PasswordGenerator.GenerateRandomString();
            empResponse = new EmployeeResponse();
            using (SqlConnection sqlConnection = new SqlConnection(ConnectionString))
            {
                if (sqlConnection.State == ConnectionState.Closed)
                {
                    sqlConnection.Open();
                }
               
                transaction = sqlConnection.BeginTransaction("ForgotPasswordTransaction");
                try
                {
                    SqlCommand cmd = new SqlCommand("uspForgotPassword", sqlConnection,transaction);
                    cmd.CommandType = CommandType.StoredProcedure;
                    cmd.Parameters.Add("@Email", SqlDbType.VarChar, 100).Value = Email;
                    cmd.Parameters.Add("@Password", SqlDbType.VarChar, 100).Value = randomPassword;
                    cmd.Parameters.Add("@PasswordSalt", SqlDbType.VarChar, 200).Value = Guid.NewGuid().ToString();
                    rowsAffected = cmd.ExecuteNonQuery();
                    if (rowsAffected > 0)
                    {
                        bool isMailSent = Mail.SendMail(Email, randomPassword);

                        if (isMailSent)
                        {
                            transaction.Commit();
                            empResponse.Status = true;
                            empResponse.Message = "New password successfully sent in your mail.";
                        }
                        else {
                            transaction.Rollback();
                            empResponse.Status = false;
                            empResponse.Message = "Problem in sending password in your mail.";
                        }
                    }
                    else {
                        transaction.Rollback();
                        empResponse.Status = false;
                        empResponse.Message = "Please check your email address and then try again.";
                    }

                }
                catch (SqlException ex)
                {
                    Logger.LogException(ex);
                    transaction.Rollback();
                    empResponse.Status = false;
                    empResponse.Message = ex.Message;
                }
            }
            return empResponse;
        }