How to save data from WPF application to file?

Question

I'm building a WPF application with Visual Studio in which I need to save data from the application to file when closing it and when I open the application, it load the data from the file to continue working. What type of file do I need to use and how to read/write the file?

In school, I know that in C++ you can read from .INP file and write on .OUT file but I guess that's not the case here. I think I could save data as text to a .txt file and convert the data to its original type but this way seems to be inefficient.

It would be better if I can read and write to the same file.

Answer 1

Here's a little sample code. You can use any file extension you want

//Allows you to perform file IO:
using System.IO;
using System.Windows;

namespace TryStuff2019 {
    public partial class MainWindow : Window {
        public MainWindow() {
            InitializeComponent();
        }

        private void BtnSaveToFile_Click(object sender, RoutedEventArgs e) {
            var saveThisToFile = "This is some sample text to save";
            var fileName = "MyOutput.txt";

            //This will save some text to a file in the same folder as your project exe file
            using(StreamWriter sw = File.CreateText(fileName)) {
                sw.Write(saveThisToFile);
            }
        }

        private void BtnReadFromFile_Click(object sender, RoutedEventArgs e) {
            var inputFileName = "MyOutput.txt";
            string fileContents;
            using(StreamReader sr = File.OpenText(inputFileName)) {
                fileContents = sr.ReadToEnd();
            }

            txtData.Text = fileContents;
        }
    }
}