Check if application is installed in registry

Question

Right now I use this to list all the applications listed in the registry for 32bit & 64. I have seen the other examples of how to check if an application is installed without any luck.

string registryKey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
RegistryKey key = Registry.LocalMachine.OpenSubKey(registryKey);
if (key != null)
{
    foreach (String a in key.GetSubKeyNames())
    {
        RegistryKey subkey = key.OpenSubKey(a);
        Console.WriteLine(subkey.GetValue("DisplayName"));
    }
}

registryKey = @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall";
key = Registry.LocalMachine.OpenSubKey(registryKey);
if (key != null)
{
    foreach (String a in key.GetSubKeyNames())
    {
        RegistryKey subkey = key.OpenSubKey(a);
        Console.WriteLine(subkey.GetValue("DisplayName"));
    }
}

So this snippet lists it all in the console window and what I am trying to do is just find one program title out of the list of display names to see if it's installed.

The last thing I tried was

if (subkey.Name.Contains("OpenSSL"))
    Console.Writeline("OpenSSL Found");
else
    Console.Writeline("OpenSSL Not Found");

Anything I tried came back either false or a false positive. Is there anyone that can show me how to just grab a title out of the list?

Please don't post up the well-known private static void IsApplicationInstalled(p_name) function. It does not work for me at all.

Answer 1

After searching and troubleshooting, I got it to work this way:

public static bool checkInstalled (string c_name)
{
    string displayName;

    string registryKey = @"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall";
    RegistryKey key = Registry.LocalMachine.OpenSubKey(registryKey);
    if (key != null)
    {
        foreach (RegistryKey subkey in key.GetSubKeyNames().Select(keyName => key.OpenSubKey(keyName)))
        {
            displayName = subkey.GetValue("DisplayName") as string;
            if (displayName != null && displayName.Contains(c_name))
            {
                return true;
            }
        }
        key.Close();
    }

    registryKey = @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall";
    key = Registry.LocalMachine.OpenSubKey(registryKey);
    if (key != null)
    {
        foreach (RegistryKey subkey in key.GetSubKeyNames().Select(keyName => key.OpenSubKey(keyName)))
        {
            displayName = subkey.GetValue("DisplayName") as string;
            if (displayName != null && displayName.Contains(c_name))
            {
                return true;
            }
        }
        key.Close();
    }
    return false;
}

And I simply just call it using

if(checkInstalled("Application Name"))

Answer 2

This is a clean way to do this without that much code.

    private static bool IsSoftwareInstalled(string softwareName)
    {
        var key = Registry.LocalMachine.OpenSubKey(@"SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall") ??
                  Registry.LocalMachine.OpenSubKey(
                      @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Uninstall");

        if (key == null)
            return false;

        return key.GetSubKeyNames()
            .Select(keyName => key.OpenSubKey(keyName))
            .Select(subkey => subkey.GetValue("DisplayName") as string)
            .Any(displayName => displayName != null && displayName.Contains(softwareName));
    }

Call it with a if-statement:

if (IsSoftwareInstalled("OpenSSL"))