How to write dictionary to computer and read it through different methods?

Question

Can you tell me why it does not work? I get an error. I tried using your method but it does not seem like it is working.

public void OnSignOut(int pin)
    {
        if (this.pin == pin && this.SignIn == true)
        {

            stopwatch.Stop();
            double elasped = stopwatch.Elapsed.TotalSeconds;
            stopwatch.Reset();
            this.total += elasped;
            MessageBox.Show("You have worked for " + elasped + " seconds." + " You have worked for " + this.total + " seconds in total.");
            this.SignIn = false;
            this.end = Convert.ToString(DateTime.Now);
            this.log.Add(this.name + " worked for " + elasped + " seconds." + "\r\n" + "Total Time: " + this.total + " seconds" + "\r\n" + "Log in: " + this.start + "   Log out: " + this.end + "\r\n\r\n\r\n");
            this.logbook.Add(DateTime.Now, elasped);
            json = JsonConvert.SerializeObject(this.logbook);
            System.IO.File.WriteAllText(@"D:\path.json", json);

        }

    }
    public double AddUp_Hours(DateTime start_date, DateTime end_date)
    {
    System.IO.File.ReadAllText(@"D:\path.json");
    this.logbook = JsonConvert.DeserializeObject<Dictionary< DateTime, double> > (json);
        DateTime first = start_date;
        DateTime second = end_date;
        double sums = this.logbook.Where(x => x.Key > first && x.Key < second)
              .Sum(x => x.Value);
        return sums;

Sounds like a data storage/serialization or DB scenario, isn't it? — wp78de, May 27 '18 at 05:15
The simplest way to do it is to serialize the data. Alternatively you could use a local database like SQLite. — ProgrammingLlama, May 27 '18 at 05:20
I've given you enough information to research how to achieve what you want to do. I'm afraid I don't have time to show you how to do it. — ProgrammingLlama, May 27 '18 at 05:23
Are you assigning the result of ReadAllText, arn't you? string json = ReadAllText(@"D:\path.json"); — wp78de, May 27 '18 at 06:58
Nice, Feel free to [accept](http://www.stackoverflow.com/tour). — wp78de, May 28 '18 at 17:47
You've said you get an error. It would be very helpful if you could tell us what the error is. — anaximander, Jun 07 '18 at 14:28

wp78de · Answer 1 · 2018-05-27T06:16:15.977

1

You have a number of options, depending on your needs regarding scalability, features, security, etc:

use the app-settings as key-value storage: if you only very little data, no strings attached
serialize your data to XML/JSON/Binary: if you have some more data, and value data portability
use a light-weight file-based database storage like SQLite: if you have quite some data, need to do some basic reporting, etc.
use a full-fledged database if you have a massive amount of data, intend to do reporting, load balancing, replication, and much more.

Assuming you look for a small-scale, low-bar data-storage solution: Try Serialization to JSON for a start

using Newtonsoft.Json;
using System;
using System.Collections.Generic;

namespace Dict2JsonSO
{
    class Program
    {
        static void Main(string[] args)
        {

            Dictionary<DateTime, int> dict = new Dictionary<DateTime, int>();
            dict.Add(DateTime.Now, 100);
            dict.Add(DateTime.Now.AddSeconds(10), 10);

            //save
            string json = JsonConvert.SerializeObject(dict);
            System.IO.File.WriteAllText(@"D:\path.txt", json);

            //load
            string loadedJson = System.IO.File.ReadAllText(@"D:\path.txt");
            Dictionary<DateTime, int> loaded = JsonConvert.DeserializeObject<Dictionary<DateTime, int>>(loadedJson);
        }
    }
}

PS: This requires Newtonsoft.Json. Install it via NuGet.

edited May 27 '18 at 06:16

answered May 27 '18 at 05:42

wp78de

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Hey, I tried to do what you told me to do but it did not work. Do you think it is because I made a mistake or is it because your way is not possible?Take a look at my edit if you can :). – Daniel May 27 '18 at 06:00
@Daniel Have you installed Newtonsoft.Json as noted? – wp78de May 27 '18 at 06:01
Hold on, I think it may have worked. – Daniel May 27 '18 at 06:03
WriteAllText(@"C:\Users\your\Desktop\storage.json") / ReadAllText(@"C:\Users\your\Desktop\storage.json") ? – wp78de May 27 '18 at 06:10
Hey my friend, the text file is saved but when I try to access it I get "System.ArgumentNullException: 'Value cannot be null. Parameter name: value'" – Daniel May 27 '18 at 06:12
See the update, read storage.json to string, then deserialize to your dict. – wp78de May 27 '18 at 06:17
I still get the same thing. I don't understand why. – Daniel May 27 '18 at 06:25
is the storage.json file actually written and the content present? – wp78de May 27 '18 at 06:28
yes the json file is written. – Daniel May 27 '18 at 06:29
Back to square one, if you copy the sample from above to a new console app, save, install Newtonsoft.Json via NuGet, build, and debug up to the line where the file gets loaded: what do you see, is the file content loaded to the string? – wp78de May 27 '18 at 06:41
Yes your code works on console. – Daniel May 27 '18 at 06:45
I am glad to hear that.. Since you have proved it works you should be able to apply it to your code. – wp78de May 27 '18 at 06:47
Now I dont get an exception but it does not seem to read it. – Daniel May 27 '18 at 06:52

How to write dictionary to computer and read it through different methods?

1 Answers1