Code:
public void InsertRegister(string userName, string password, string sex, string email)
        {
            try
            {
                string query = "INSERT INTO login (userid, user_pass, sex, email) VALUES('" + userName + "', '" + password + "', '" + sex + "', '" + email + "')";

                //open connection

                if (this.OpenConnection() == true)
                {
                    //create command and assign the query and connection from the constructor
                    MySqlCommand cmd = new MySqlCommand(query, connection);

                    //Execute command
                    cmd.ExecuteNonQuery();
                    MessageBox.Show("Register Successful.");
                   
                }
            }
            catch (Exception ex)
            {
                if (ex.Message.IndexOf("_userid") >= 0)
                    MessageBox.Show("That username already exists. Please change the login name.");

                else
                    MessageBox.Show(ex.Message);
            }
            finally
            {
                //close connection
                this.CloseConnection();
            }
        }
on class.cs this is not a form
MessageBox.Show("Register Successful.");
i want the all textbox will be clear on form that will assign class to do it when it success.