How to add data in list to .txt file with switch-case

Question

0.00/5 (No votes)

See more:

i have Controller and Person classes,i need to add data in my list,All data that is added to the Console must be stored in a .txt file.That is, if the user inputs 1 to see the datas, it must be read from the file then displayed, when the user inputs 2 to add new data,it must be read from the file then displayed.
i have already written the Show() function,it's working,but add() function doesn't work,what's false i have?

What I have tried:

class Controller
    {
        public List<Person> all; 
        public void Show()
        {
            string path = "C:/Users/User/Desktop/mardik.txt";
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read);
            BinaryFormatter bf = new BinaryFormatter();
            List<Person> all = bf.Deserialize(fs) as List<Person>;
            foreach (Person item in all)
            {
                Console.WriteLine(item.name + " " + item.age);
            }
        }
        public void Add()
        {
            string path = "C:/Users/User/Desktop/mardik.txt";
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Read);
            BinaryFormatter bf = new BinaryFormatter();
            List<Person> all = bf.Deserialize(fs) as List<Person>;
            
            Console.WriteLine("Enter new user's data");
            string text = Console.ReadLine();
            
            foreach(Person item in all)
            {
                Console.WriteLine(item.name + " " + item.age);
            }
        }

What is my Mistake in Add() function?

[Serializable]
    class Person
    {
        public string name;
        public int age;
        public Person(string a, int b)
        {
            this.name = a;
            this.age = b;
        }
    }

static void Main(string[] args)
        {
            string path = "C:/Users/User/Desktop/mardik.txt";
            List<Person> mardik = new List<Person>();
            //mardik.Add(new Person("Valod", 20));
            //mardik.Add(new Person("Petros", 23));
            //mardik.Add(new Person("Poghos", 25));
            //mardik.Add(new Person("Hranush", 22));
            //mardik.Add(new Person("Suren", 18));
            //FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.Write);
            //BinaryFormatter bf = new BinaryFormatter();
            //bf.Serialize(fs, mardik);
            //fs.Close();
            Controller c = new Controller();
            while (true)
            {
                Console.WriteLine();
                Console.WriteLine("What do you want to do:\n1.Show all People\n2.Add new person\n3.Delete any person");
                int x = int.Parse(Console.ReadLine());
                switch (x)
                {
                    case 1:
                        c.Show();
                        break;
                    case 2:
                        c.Add();
                        break;
                    
                }
            }
        }

Posted 14-Feb-18 22:19pm

Suren97

Updated 15-Feb-18 3:47am

Add a Solution

Comments

Richard MacCutchan 15-Feb-18 4:25am

You forgot to include the code to rewrite the file after the new data has been input. A better structure for your program would be:

Start:
    Read the input file data into the List
    While user select options:
        if 1 then show List
    Else
        if 2 then add new entry
    Else
        if some_other_value the end while loop
If new entries added
    Write entries to new file
End:

Suren97 15-Feb-18 5:49am

i don't understand, can you show me it as code?

Richard MacCutchan 15-Feb-18 5:52am

I have given you the pseudo-code, converting that to C# is not difficult.

Suren97 15-Feb-18 5:54am

but i think i have done like that, or i just don't understand what you mean?

Richard MacCutchan 15-Feb-18 6:08am

Sorry, but you have not. Look at the structure of your code. You read the input file in two places, so you create two separate lists of objects; that is just duplicating work. And it also means that every time you call Show or Add you re-read the file again, which is even more wasteful. Other issues as listed in OriginalGriff's message below.

Suren97 15-Feb-18 6:08am

Please if you can show me how should i write that code? then i will try to write the function delete() myself :)

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

OriginalGriff · Answer 1 · 2018-02-14T22:33:00

Solution 1

Couple of things here:
1) Don't hardcode paths, use a config file instead - and if you can't work that out, then use a const value so you only have to change it in one place.
2) If you open a file or stream, you are responsible for closing and Disposing of it: none of your code does that, which means the stream remains open until either the app closes or the Garbage Collector gets kicked in to clean up after you. If a file is open, you can;t open it for writing!
3) Your add method reads data from the user, but does nothing with it: it is discarded at the end of the method, so there is little point in reading it in the first place!
4) Using the .TXT extension is misleading when you use a BinaryFormatter - it implies human readable and editable content, which a BinaryFormatter does not produce.
5) Never trust user input: int.Parse will throw an exception is the user enters "hello" or "A" instead of a digit. I'd suggest you use int.TryParse instead.

I'd suggest that you look at using blocks around your Streams and Formatters, and that you look at appending the new data from the user to your file as part of you Add method, as well as displaying it in some way.

Posted 14-Feb-18 22:33pm

OriginalGriff

Updated 14-Feb-18 22:35pm

v2

Comments

Suren97 15-Feb-18 6:27am

How can i use config file?

OriginalGriff 15-Feb-18 6:36am

https://msdn.microsoft.com/en-us/library/ms184658.aspx

Suren97 15-Feb-18 6:30am

or const value?

OriginalGriff 15-Feb-18 6:37am

You are kidding, right?

const string myConstValue = "Value of the string";

Suren97 15-Feb-18 6:39am

for what i should use it?

OriginalGriff 15-Feb-18 6:50am

Instead of writing the path to your file each time, you declare it as a const value, and use the name of the const each time you want the path. That way, if you move the file, you only have to change one location in the app and recompile so it's more reliable, and less prone to errors.
It's not as flexible as a config file - you still have to recompile the application each time you move the file - but it's a lot better than typing in the path each time!

Suren97 15-Feb-18 6:41am

it always given me exception :(

OriginalGriff 15-Feb-18 6:51am

Then you need to find out what the exception is and why you are getting it ... remember that we can't see your screen, access your HDD, or read your mind - we only get exactly what you type to work with.

Suren97 15-Feb-18 7:26am

Thank you very much, i could do it, but there is one problem, when i write new data it adding my list, but then when i enter 1 to see my all people + my adding person, it there is not

OriginalGriff 15-Feb-18 7:37am

That's because you aren't doing anything with the data!
To do that, you need to append it to the file - and that means sorting out the other things I mentioned, or the file will not be able to open for writing.

Suren97 15-Feb-18 7:45am

How can i append? File.AppendAllLines(?)

OriginalGriff 15-Feb-18 7:54am

Not without fixing your Streams and Formatters - if the file is in use, you can't write to it!

Suren97 15-Feb-18 7:59am

what should i do?

OriginalGriff 15-Feb-18 8:30am

Read what I said in my original answer.

Suren97 15-Feb-18 9:17am

i don't understand,where should I make changes?

OriginalGriff 15-Feb-18 9:26am

What part of what I originally wrote do you not understand? If you tell us, we can help. But just going "I don't know, what do I do?" doesn't help anyone!

Suren97 15-Feb-18 9:32am

Look my solution below.

Suren97 15-Feb-18 10:50am

have you seen?

OriginalGriff 15-Feb-18 11:02am

You posted it as a solution, so I assume you are finished.

Suren97 15-Feb-18 11:23am

noo,i just didn't knew how can i posted it as a code,now i need only to save my adding data.

OriginalGriff 15-Feb-18 11:38am

That's very bad code.
Why are you recursively calling yourself when you get an error? You do realise that will return at the end...

Suren97 15-Feb-18 7:27am

How can i save my adding data ?

Suren97 · Answer 2 · 2018-02-15T03:31:00

public void Add()
        {
            const string path = "C:/Users/User/Desktop/mardik.txt";
            FileStream fs = new FileStream(path, FileMode.OpenOrCreate, FileAccess.ReadWrite);
            BinaryFormatter bf = new BinaryFormatter();
            List<Person> all = bf.Deserialize(fs) as List<Person>;
            fs.Close();
            Console.WriteLine("Enter new user's data with comma");
            string text = Console.ReadLine();
            string[] segments = text.Split(',');
            string a = segments[0];
            int b;
            bool hajoxvec = int.TryParse(segments[1], out b);
            if (!hajoxvec)
            {
                Console.WriteLine("Please try again");
                this.Add();
            }
            else
            {
                all.Add(new Person(a, b));

            }
                foreach (Person item in all)
                {
                    Console.WriteLine(item.name + " " + item.age);
                }
            fs.Close();
        }

it's working, now i need only to save my adding data.