How can I find the upgrade code for an installed application in C#?

Question

I am using the C# wrapper for the Windows Installer API from the WIX Toolset. I use the ProductInstallation class to get information about the installed produc

Answer 1

This is the opposite method to get the ProductCode from an UpgradeCode. Could be useful for somebody.

using Microsoft.Win32;
using System;
using System.IO;
using System.Linq;
using System.Text;

internal static class RegistryHelper
{
    private const string UpgradeCodeRegistryKey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Installer\UpgradeCodes";

    private static readonly int[] GuidRegistryFormatPattern = new[] { 8, 4, 4, 2, 2, 2, 2, 2, 2, 2, 2 };


    public static Guid? GetProductCode(Guid upgradeCode)
    {
        // Convert the product code to the format found in the registry
        var productCodeSearchString = ConvertToRegistryFormat(upgradeCode);

        // Open the upgrade code registry key
        var upgradeCodeRegistryRoot = GetRegistryKey(Path.Combine(UpgradeCodeRegistryKey, productCodeSearchString));

        if (upgradeCodeRegistryRoot == null)
            return null;

        var uninstallCode = upgradeCodeRegistryRoot.GetValueNames().FirstOrDefault();
        if (string.IsNullOrEmpty(uninstallCode))
        {
            return null;
        }

        // Convert it back to a Guid
        return ConvertFromRegistryFormat(uninstallCode);
    }





    private static string ConvertToRegistryFormat(Guid code)
    {
        return Reverse(code, GuidRegistryFormatPattern);
    }

    private static Guid ConvertFromRegistryFormat(string code)
    {
        if (code == null || code.Length != 32)
            throw new FormatException("Product code was in an invalid format");

        code = Reverse(code, GuidRegistryFormatPattern);

        return Guid.Parse(code);
    }

    private static string Reverse(object value, params int[] pattern)
    {
        // Strip the hyphens
        var inputString = value.ToString().Replace("-", "");

        var returnString = new StringBuilder();

        var index = 0;

        // Iterate over the reversal pattern
        foreach (var length in pattern)
        {
            // Reverse the sub-string and append it
            returnString.Append(inputString.Substring(index, length).Reverse().ToArray());

            // Increment our posistion in the string
            index += length;
        }

        return returnString.ToString();
    }

    static RegistryKey GetRegistryKey(string registryPath)
    {
        var hklm64 = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry64);
        var registryKey64 = hklm64.OpenSubKey(registryPath);
        if (((bool?)registryKey64?.GetValueNames()?.Any()).GetValueOrDefault())
        {
            return registryKey64;
        }

        var hklm32 = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32);
        return hklm32.OpenSubKey(registryPath);
    }
}