Backup Registry Key Values

Question

Hello all I need to backup and restore a registry key using vb.net (or c#), key is Current User, no need special access grant: HKEY_CURRENT_USER\SOFTWARE\ACME\Product\KeyToBackup Just need the values under the key to be saved, I mean if there are sub keys inside, no need them. Is there any .net method for that (.net fw 4 full profile) or I just read them manually and save to a file? And about the save format, what you guys recommend?

Answer 1

Hi @Peter Volz ,Welcome to Microsoft Q&A. Do you mean you want to get the default value of the registry "HKEY_CURRENT_USER\SOFTWARE\ACME\Product\KeyToBackup" and backup and restore it? Manipulating the current user's registry does not require permissions. I created a project using Winform (.Net Framework 4.8). There are two methods: one is to query whether the target key exists, and if it exists, it will save the default value of the target key in the target txt file. The second method is to find out whether the target backup file exists, and restore the key value if it exists. Here's the code:

using Microsoft.Win32;
using System;
using System.IO;
using System.Windows.Forms;

namespace WindowsFormsApp5
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        string keyPath = @"SOFTWARE\ACME\Product\KeyToBackup"; // registry key path
        string backupFilePath = @"C:\backup.txt"; // Registry backup file path


        static void BackupRegistryKey(string keyPath, string backupFilePath)
        {
            // Check if the registry key exists
            RegistryKey regKey = Registry.CurrentUser.OpenSubKey(keyPath);
            if (regKey == null)
            {
                Console.WriteLine("Registry key does not exist: " + keyPath);
                return;
            }

            // Backup registry keys to text file
            using (StreamWriter writer = new StreamWriter(backupFilePath))
            {
                string[] valueNames = regKey.GetValueNames();
                foreach (string valueName in valueNames)
                {
                    if (valueName == @"")
                    {
                        string value = regKey.GetValue(valueName)?.ToString();
                        writer.WriteLine($"{valueName}={value}");
                    }
                }
            }
        }

        static void RestoreRegistryKey(string keyPath, string backupFilePath)
        {
            // Check if the backup file exists
            if (!File.Exists(backupFilePath))
            {
                Console.WriteLine("Backup file does not exist: " + backupFilePath);
                return;
            }

            // Read registry backup and restore from text file
            using (StreamReader reader = new StreamReader(backupFilePath))
            {
                string line;
                // Pay attention to use the open method with write permission
                RegistryKey regKey = Registry.CurrentUser.OpenSubKey(keyPath, true);
                if (regKey == null)
                {
                    Console.WriteLine("Registry key does not exist: " + keyPath);
                    return;
                }

                while ((line = reader.ReadLine()) != null)
                {
                    string[] parts = line.Split('=');
                    string valueName = parts[0];
                    string valueData = parts[1];

                    // restore registry keys
                    regKey.SetValue(valueName, valueData);
                    Console.WriteLine($"Restored value: {valueName}={valueData}");
                }
            }
        }

        private void button1_Click(object sender, EventArgs e)
        {
            // Backup registry keys to text file
            BackupRegistryKey(keyPath, backupFilePath);
            Console.WriteLine("Registry key backed up to: " + backupFilePath);
        }

        private void button2_Click(object sender, EventArgs e)
        {
            // Read registry backup and restore from text file
            RestoreRegistryKey(keyPath, backupFilePath);
            Console.WriteLine("Registry key restored successfully.");
        }
    }
}

Here's the demo:

Best Regards,

Jiale

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