Detect framework version at application runtime

Question

How I could detect at application runtime

what version numbers of .NET framework are installed on the client machine?

Answer 1

private static void GetVersionFromRegistry()
{
    using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine,
        RegistryView.Registry32).OpenSubKey(@"SOFTWARE\Microsoft\NET Framework Setup\NDP\"))
    {
        foreach (string versionKeyName in ndpKey.GetSubKeyNames())
        {
            if (versionKeyName.StartsWith("v"))
            {

                RegistryKey versionKey = ndpKey.OpenSubKey(versionKeyName);
                string name = (string)versionKey.GetValue("Version", "");
                string sp = versionKey.GetValue("SP", "").ToString();
                string install = versionKey.GetValue("Install", "").ToString();
                if (install == "") //no install info, ust be later
                    Console.WriteLine(versionKeyName + "  " + name);
                else
                {
                    if (sp != "" && install == "1")
                    {
                        Console.WriteLine(versionKeyName + "  " + name + "  SP" + sp);
                    }

                }
                if (name != "")
                {
                    continue;
                }
                foreach (string subKeyName in versionKey.GetSubKeyNames())
                {
                    RegistryKey subKey = versionKey.OpenSubKey(subKeyName);
                    name = (string)subKey.GetValue("Version", "");
                    if (name != "")
                        sp = subKey.GetValue("SP", "").ToString();
                    install = subKey.GetValue("Install", "").ToString();
                    if (install == "") //no install info, ust be later
                        Console.WriteLine(versionKeyName + "  " + name);
                    else
                    {
                        if (sp != "" && install == "1")
                        {
                            Console.WriteLine("  " + subKeyName + "  " + name + "  SP" + sp);
                        }
                        else if (install == "1")
                        {
                            Console.WriteLine("  " + subKeyName + "  " + name);
                        }

                    }

                }

            }
        }
    }
}

resources info : http://msdn.microsoft.com/en-us/library/hh925568%28v=vs.110%29.aspx