How do I save and reference user input c# (ToDo Console app) [closed]-CodePudding

I'm new to C# and as my first "program", I want to build a ToDo-list app that runs in console.

I've laid down the basic frame of the program, but I do not seem to find how to save user data outside of the main code and so that it can be referenced again in the next session.

I do not want to save the tasks as variables temporarily.

My idea how my app would work is that if I open the program and I have the choice to either write/add a task or read the tasks.

If I write a new task the console should display the updated ToDo list with the newest task in addition to tasks i added in past sessions.

Right now I don't plan to add a "delete task" button, maybe after I understand how to solve the first problem. I am using VisualStudio for mac if that is relevant.

CodePudding user response：

There are many ways this can be done.

One of the easiest and most commonly used is with JSON.

Here is a complete program I wrote so that you can experiment with.

public class TodoItem
{
    public string Description { get; set; }
    public DateTime? DueOn { get; set; }

    public override string ToString()
    {
        return $"{this.Description}";
    }
}

internal static class Program
{
    static private readonly string _saveFileName = "todo.json";
    static void Main()
    {
        {
            // An example list containing 2 items
            List<TodoItem> items = new List<TodoItem> {
                new TodoItem { Description = "Feed the dog" },
                new TodoItem { Description = "Buy groceries", DueOn = new DateTime(2021, 9, 30, 16, 0, 0) }
            };
            // Serialize it to JSON
            string json = JsonSerializer.Serialize(items, new JsonSerializerOptions() { WriteIndented = true });

            // Save it to a file
            File.WriteAllText(_saveFileName, json);
        }

        // Now we'll load the list back from the file
        {
            string json = File.ReadAllText(_saveFileName);

            List<TodoItem> items = JsonSerializer.Deserialize<List<TodoItem>>(json);

            // Check whether the list has loaded correctly
            foreach (var todo in items)
                Console.WriteLine(todo);
        }

    }

Program output:

Feed the dog
Buy groceries

todo.json file contents:

[
  {
    "Description": "Feed the dog",
    "DueOn": null
  },
  {
    "Description": "Buy groceries",
    "DueOn": "2021-09-30T16:00:00"
  }
]

CodePudding user response：

You can store Data in a File

using System.IO;

string pathToFile = "myTodoList.txt";
string[] lines = new string[]{"task1","task2","task3");

File.WriteAllLine(pathToFile,lines);

in the txt you will find:

task1 
task2 
task3

and reading them:

using System.IO;

string pathToFile = "myTodoList.txt";
string[] lines = File.readAllLines(pathToFile);

foreach(string line in lines)
{
     Console.ReadLine(line);
}