Pretest - Allan's Store

Class as follows:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace AllanStore
{
    public class ComputerSystem
    {
        //fields
        private int barcode;
        private string description;      
        private string model;       
        private double price;
        private Brand brand;

        //properties
        public int Barcode
        {
            get { return barcode; }
            set { barcode = value; }
        }
        public string Description
        {
            get { return description; }
            set { description = value; }
        }
        public string Model
        {
            get { return model; }
            set { model = value; }
        }
        public double Price
        {
            get { return price; }
            set { price = value; }
        }
        public Brand Brand
        {
            get { return brand; }
            set { brand = value; }
        }

        //constructors
        public ComputerSystem()
        {
        }

        public ComputerSystem(int _barcode, string _description, Brand _brand, string _model, double _price)
        {
            this.barcode = _barcode;
            this.description = _description;
            this.brand = _brand;
            this.model = _model;
            this.price = _price;
        }

        //methods
        public override string ToString()
        {
            return "" + barcode.ToString() + ", " + description.ToString() + ", " + brand.ToString() + ", " + model.ToString() + ", $" + price.ToString() + "\n";
        }


    }
}

Enum as follow:

public enum Brand
{
    Asus=0,
    Dell=1,
    Hp=2,
    Acer=3
}

Form as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace AllanStore
{
    public partial class Form1 : Form
    {
        //fields
        private ComputerSystem[] computerArray = new ComputerSystem[10];

        //properties
        public ComputerSystem[] ComputerArray
        {
            get { return computerArray; }
            set { computerArray = value; }
        }

        //constructors
        public Form1()
        {
            InitializeComponent();
        }

        //methods - EVENTS
        private void exitToolStripMenuItem_Click(object sender, EventArgs e)
        {
            DialogResult msg = MessageBox.Show("Are you sure?", "Exit", MessageBoxButtons.YesNo);
            if (msg == DialogResult.Yes)
            {
                Close();
            }
        }

        private void btnExit_Click(object sender, EventArgs e)
        {
            exitToolStripMenuItem_Click(sender, e);
        }

        private void addToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (checkAllFields() == true)   //valid
            {
                ComputerSystem addObj = new ComputerSystem();
                addObj.Barcode = int.Parse(txtBarcode.Text);
                addObj.Price = double.Parse(txtPrice.Text);
                addObj.Brand = (Brand)cmbBrand.SelectedItem;
                addObj.Description = txtDescription.Text;
                addObj.Model = txtModel.Text;

                bool result = addSystem(addObj);

                if (result == true)
                {
                    MessageBox.Show("Computer System added!", "Added");
                }
                else
                {
                    MessageBox.Show("Cannot Add, Array full!", "Cannot Add");
                }
                
            }
        }

        //methods - User defined
        public void clearAllFields()
        {
            txtBarcode.Text = "";
            cmbBrand.Text = "";
            txtDescription.Text = "";
            txtModel.Text = "";
            txtPrice.Text = "";
        }

        public bool checkAllFields()
        {
            try
            {
                //fields errors
                string errormessage = "";

                if ((txtBarcode.Text == "") || (cmbBrand.Text == "") || (txtDescription.Text == "") || (txtModel.Text == "") || (txtPrice.Text == ""))
                {
                    errormessage = "Please enter all fields";
                }

                //type errors
                ComputerSystem testObj = new ComputerSystem();

                testObj.Barcode = int.Parse(txtBarcode.Text);
                testObj.Price = double.Parse(txtPrice.Text);
                testObj.Brand = (Brand)cmbBrand.SelectedItem;

                if (errormessage != "")
                {
                    MessageBox.Show(errormessage, "Error occurred");
                    return false;
                }
                else
                    return true;


            }
            catch   //catch type errors
            {
                MessageBox.Show("Please enter correct values in fields", "Error occurred");
                return false;
            }
        }
        public bool addSystem(ComputerSystem addObj)
        {
            for (int i = 0; i < computerArray.Length; i++)
            {
                if (computerArray[i] == null)
                {
                    //perform add
                    computerArray[i] = addObj;
                    return true;
                }
            }
            return false;
        }

        private void btnAdd_Click(object sender, EventArgs e)
        {
            addToolStripMenuItem_Click(sender, e);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            cmbBrand.Items.Add(Brand.Acer);
            cmbBrand.Items.Add(Brand.Asus);
            cmbBrand.Items.Add(Brand.Dell);
            cmbBrand.Items.Add(Brand.Hp);
        }

        private void btnSearch_Click(object sender, EventArgs e)
        {
            searchToolStripMenuItem_Click(sender, e);
        }

        private void searchToolStripMenuItem_Click(object sender, EventArgs e)
        {
            try
            {
                ComputerSystem foundObj = new ComputerSystem();
                foundObj = searchSystem(txtBarcode.Text);

                if (foundObj == null)
                {
                    MessageBox.Show("Cannot find Computer System", "No search found");
                }
                else
                {
                    MessageBox.Show("System found");
                    txtBarcode.Text = foundObj.Barcode.ToString();
                    txtDescription.Text = foundObj.Description;
                    txtModel.Text = foundObj.Model;
                    txtPrice.Text = foundObj.Price.ToString();
                    cmbBrand.Text = foundObj.Brand.ToString();
                }
                

            }
            catch
            {
                MessageBox.Show ("Barcode not valid", "Error");
            }
                    
        }

        public ComputerSystem searchSystem(string sbarcode)
        {
            try
            {
                int barcode = int.Parse(sbarcode);
            
                for (int i = 0; i < computerArray.Length; i++)
                {
                    if ((computerArray[i] != null) && (computerArray[i].Barcode == barcode)) //found match
                    {
                        return computerArray[i];
                    }

                }
                return null;
            }
            catch
            {
                return null;
                
            }
        }

        private void btnUpdate_Click(object sender, EventArgs e)
        {
            updateToolStripMenuItem_Click(sender, e);
        }

        public bool updateSystem(string sbarcode, ComputerSystem updateObj)
        {
            try
            {
                int barcode = int.Parse(sbarcode);
                for (int i = 0; i < computerArray.Length; i++)
                {
                    if ((computerArray[i] != null) && (computerArray[i].Barcode == barcode))
                    {
                        computerArray[i] = updateObj;
                        return true;
                    }
                }
                return false;
            }
            catch
            {
                return false;
            }
        }

        private void updateToolStripMenuItem_Click(object sender, EventArgs e)
        {
            if (checkAllFields() == true)
            {
                ComputerSystem updateObj = new ComputerSystem();
                updateObj.Barcode = int.Parse(txtBarcode.Text);
                updateObj.Price = double.Parse(txtPrice.Text);
                updateObj.Brand = (Brand)cmbBrand.SelectedItem;
                updateObj.Description = txtDescription.Text;
                updateObj.Model = txtModel.Text;

                bool updateresult = updateSystem(txtBarcode.Text, updateObj);

                if (updateresult == true)
                {
                    MessageBox.Show("System successfully updated");
                }
                else
                {
                    MessageBox.Show("Cannot update system", "Error");
                }
            }
        }

        private void deleteToolStripMenuItem_Click(object sender, EventArgs e)
        {
            bool deleteresult = deleteSystem(txtBarcode.Text);
            if (deleteresult == true)
            {
                MessageBox.Show("System deleted");
                clearAllFields();
            }
            else
            {
                MessageBox.Show("Cannot find system", "Delete failed");
            }
        }

        public bool deleteSystem(string sbarcode)
        {
            try
            {
                int barcode = int.Parse(sbarcode);

                for (int i = 0; i < computerArray.Length; i++)
                {
                    if ((computerArray[i] != null) && (computerArray[i].Barcode == barcode))
                    {
                        computerArray[i] = null;
                        return true;
                    }
                }
                return false;
            }
            catch
            {
                return false;
            }
        }

        private void btnDelete_Click(object sender, EventArgs e)
        {
            deleteToolStripMenuItem_Click(sender, e);
        }

        private void btnDisplayAll_Click(object sender, EventArgs e)
        {
            displayAllToolStripMenuItem_Click(sender, e);
        }

        private void displayAllToolStripMenuItem_Click(object sender, EventArgs e)
        {
            string myComputers = "";
            for (int i = 0; i < computerArray.Length; i++)
            {
                if (computerArray[i] != null)
                {
                    myComputers += computerArray[i].ToString();
                }
            }

            MessageBox.Show(myComputers, "Computer Lists");
        }

        private void btnAbout_Click(object sender, EventArgs e)
        {
            AboutBox1 about = new AboutBox1();
            about.Show();
        }

        private void aboutToolStripMenuItem1_Click(object sender, EventArgs e)
        {
            btnAbout_Click(sender, e);
        }

    }
}