Listing All The Installed Softwares In Computer Using .Net

A few practical clarifications that build on @sandeepparekh9's sample and the follow-ups from @vishalrane and @Creelers. The Installer\UserData...Products tree only shows MSI products for a specific account and often leads to nulls — many installed programs register under the Uninstall keys instead. Enumerating the Uninstall keys under both HKLM and HKCU, and reading both 32-bit and 64-bit registry views, produces a far more complete list.

Important points: always check the result of OpenSubKey for null before using it; GetValue may return null so avoid calling ToString() directly; dispose RegistryKey objects (using blocks); avoid popping a MessageBox for every exception (log or skip bad entries instead). For ASP.NET (@vishalrane) this kind of registry enumeration usually fails in a default app pool because of permissions — run as a privileged scheduled task/service or use a client-side agent if the goal is to list software on user machines. Avoid WMI's Win32_Product because it is slow and can trigger MSI repairs.

Example helper (safe, checks both hives and registry views):

class InstalledProgram { public string Name; public string Version; public string Publisher; }

List<InstalledProgram> GetInstalledPrograms()
{
    var results = new List<InstalledProgram>();
    var hives = new[] { RegistryHive.LocalMachine, RegistryHive.CurrentUser };
    var views = Environment.Is64BitOperatingSystem
                ? new[] { RegistryView.Registry64, RegistryView.Registry32 }
                : new[] { RegistryView.Registry32 };

    foreach (var hive in hives)
    foreach (var view in views)
    using (var baseKey = RegistryKey.OpenBaseKey(hive, view))
    using (var uninstall = baseKey.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall"))
    {
        if (uninstall == null) continue;
        foreach (var name in uninstall.GetSubKeyNames())
        using (var sk = uninstall.OpenSubKey(name))
        {
            var disp = sk?.GetValue("DisplayName") as string;
            if (string.IsNullOrWhiteSpace(disp)) continue;
            results.Add(new InstalledProgram {
                Name = disp,
                Version = sk.GetValue("DisplayVersion") as string,
                Publisher = sk.GetValue("Publisher") as string
            });
        }
    }
    return results;
}

Troubleshooting: @Creelers' NullReferenceException is almost always caused by a null RegistryKey or a missing DisplayName; protect every OpenSubKey/GetValue call and skip entries that lack DisplayName.