public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
        {
            Visibility rv = Visibility.Visible;

            if (value != null)
            {
                TriStateBoolean theValue = (TriStateBoolean)value;
                if (theValue.HasValue)
                {
                    if (theValue.IsFalse)
                    {
                        rv = Visibility.Hidden;
                    }
                }
            }
            return(rv);
        }
        /// <summary>
        /// Retrieve the indicated integer value from the Windows Registry, from under subkeyPath (which is under BaseKeyPath).
        /// If the retrieval fails then the provided default value is returned.
        /// </summary>
        /// <param name="valueName">the name of the Registry value to retrieve it from</param>
        /// <param name="defaultValue">the default value to return if the retrieval fails</param>
        /// <param name="subkeyPath">the Registry subkey (under BaseKeyPath) under which to retrieve it from</param>
        /// <returns>The value from the Registry, or the default value if there's a failure</returns>
        protected TriStateBoolean GetTriStateBoolean(string valueName, bool?defaultValue, string subkeyPath = null)
        {
            TriStateBoolean result = TriStateBoolean.From(defaultValue);
            int             integerDefaultValue = result.NumericValue;

            using (var registryKey = this.OpenSubkeyUnderBasekey(false, subkeyPath))
            {
                if (registryKey != null)
                {
                    int integerValue = (int)registryKey.GetValue(valueName, integerDefaultValue);
                    result = TriStateBoolean.From(integerValue);
                }
                else
                {
                    Console.WriteLine("in RegistryBase.GetTriStateBoolean(" + valueName + ",), access failed so returning the default value.");
                }
            }
            return(result);
        }