Editing .txt file based on list

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Hi,

I'm trying to write code that will take the contents of a text file, make changes to only specific lines based on the contents of a list.

E.G. I have a .txt of products with the format: ID, name, quantity, $price
I then have a list (cartList) that contains the items the user has added to the cart.
I want to make it so on buttonClick, the text file is edited so that all products that were in the cartList have 1 less quantity.

I'm new to coding, and I'm more than happy to scrap this code if it's not close.

Thank you.

What I have tried:

C#

<pre>
private void btnCheckout_Click(object sender, RoutedEventArgs e)
        {
List<string> replaceList = new List<string>();
            List<string> tempList = new List<string>();
            StreamReader sr = new StreamReader("items.txt");
            while (!sr.EndOfStream)
            {
                tempList.Add(sr.ReadLine());
                string content = sr.ReadLine();
                foreach(string i in cartList)
                {
                    if (i == content)
                    {
                        string[] splitItem = content.Split(',');
                        decimal y = decimal.Parse(splitItem[2]) - 1;
                        string x = (splitItem[0] + ", " + splitItem[1] + ", " + y + ", " + splitItem[3]);
                        replaceList.Add(x);
                    }
                   foreach (string t in tempList)
                    {
                        if (t == i)
                        {
                            tempList.Remove(t);
                            break;
                        }
                    }
                }                
            }
            sr.Close();          

           
            foreach (string x in tempList)
            {
                replaceList.Add(x);
            }

            File.Delete("items.txt");

            StreamWriter sw = new StreamWriter("items.txt");
            foreach (string r in replaceList)
            {
            sw.WriteLine(r);
            }
            sw.Close();
}

Posted 18-Oct-21 12:32pm

Member 15382039

Updated 18-Oct-21 20:32pm

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Comments

BillWoodruff 19-Oct-21 3:10am

What happens when you run your code ? Errors ? Unexpected results ?

Are you the person who creates the data/text file ?

Why aren't you using a database ?

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Maciej Los · Answer 1 · 2021-10-18T20:32:00

Quote:
I have a .txt of products with the format: ID, name, quantity, $price
I then have a list (cartList) that contains the items the user has added to the cart.
I want to make it so on buttonClick, the text file is edited so that all products that were in the cartList have 1 less quantity.

So, you have to have a Product class and a list of products, instead of list of strings.
For eaxmple:

C#

class Product
{
	private int id = 0;
	private string name = string.Empty;
	private double price = .0;
	
	public Product(int _id, string _name, double _price)
	{
		id = _id;
		name = _name;
		price = _price;
	}
	
	public int ID
	{
		get => id;
		set => id = value;
	}
	
	public string Name
	{
		get => name;
		set => name = value;
	}
	
	public double Price
	{
		get => price;
		set => price = value;
	}

}

Then, you have to use that class.

List<Product> products = new List<Product>();
products.Add(new Product(1, "Apple", 5.55));
products.Add(new Product(2, "Orange", 6.11));
products.Add(new Product(3, "Coconut", 7.33));
	
Console.WriteLine($"Quantity: {products.Count()}");
Console.WriteLine($"Total price: {products.Sum(x=>x.Price)}");

Whenever you add/remove product to the list of products, you can easily calculate a quantity, sum, etc.

To be able to put a list of products to the text file (and then reverse the process), please, read about Serialization[^].

Good luck!