System.Environment.GetEnvironmentVariablesCore C# (CSharp) Method

        private static IDictionary GetEnvironmentVariablesCore(EnvironmentVariableTarget target)
        {
            if (target == EnvironmentVariableTarget.Process)
            {
                return GetEnvironmentVariablesCore();
            }
            else
            {
                RegistryKey baseKey;
                string keyName;
                if (target == EnvironmentVariableTarget.Machine)
                {
                    baseKey = Registry.LocalMachine;
                    keyName = @"System\CurrentControlSet\Control\Session Manager\Environment";
                }
                else
                {
                    Debug.Assert(target == EnvironmentVariableTarget.User);
                    baseKey = Registry.CurrentUser;
                    keyName = @"Environment";
                }

                using (RegistryKey environmentKey = baseKey.OpenSubKey(keyName, writable: false))
                {
                    var table = new LowLevelDictionary<string, string>();
                    if (environmentKey != null)
                    {
                        foreach (string name in environmentKey.GetValueNames())
                        {
                            table.Add(name, environmentKey.GetValue(name, "").ToString());
                        }
                    }
                    return table;
                }
            }
        }