ConverterHelper.cs

  public static class ConverterHelper {
      public static int AsInt([CanBeNull] this object value) {
          return value.AsInt(0);
      }

      public static int AsInt([CanBeNull] this string value) {
          return value.AsInt(0);
      }

      public static int AsInt([CanBeNull] this object value, int defaultValue) {
          return value as int? ?? value?.ToString().AsInt(defaultValue) ?? defaultValue;
      }

      public static int AsInt([CanBeNull] this string value, int defaultValue) {
          int result;
          if (value == null || !int.TryParse(value, NumberStyles.Any, CultureInfo.InvariantCulture, out result)) {
              return defaultValue;
          }

          return result;
      }

      public static double AsDouble([CanBeNull] this object value) {
          return value.AsDouble(0);
      }

      public static double AsDouble([CanBeNull] this string value) {
          return value.AsDouble(0);
      }

      public static double AsDouble([CanBeNull] this object value, double defaultValue) {
          return value as double? ?? value?.ToString().AsDouble(defaultValue) ?? defaultValue;
      }

      public static double AsDouble([CanBeNull] this string value, double defaultValue) {
          double result;
          if (value == null || !double.TryParse(value, NumberStyles.Any, CultureInfo.InvariantCulture, out result)) {
              return defaultValue;
          }

          return result;
      }

      public static bool AsBoolean([CanBeNull] this object value) {
          return value.AsBoolean(false);
      }

      public static bool AsBoolean([CanBeNull] this string value) {
          return value.AsBoolean(false);
      }

      public static bool AsBoolean([CanBeNull] this object value, bool defaultValue) {
          return value as bool? ?? value?.ToString().AsBoolean(defaultValue) ?? defaultValue;
      }

      public static bool AsBoolean([CanBeNull] this string value, bool defaultValue) {
          bool result;
          if (value == null || !bool.TryParse(value, out result)) {
              return defaultValue;
          }

          return result;
      }

      public static bool XamlEquals([CanBeNull] this object properValue, [CanBeNull] object xamlValue) {
          if (properValue == null) return xamlValue == null;
          if (xamlValue == null) return false;

          if (properValue is double) {
              return Equals((double)properValue, xamlValue.AsDouble());
          }

          if (properValue is int) {
              return Equals((int)properValue, xamlValue.AsInt());
          }

          if (properValue is bool) {
              return Equals((bool)properValue, xamlValue.AsBoolean());
          }

          if (properValue is string) {
              return Equals((string)properValue, xamlValue.ToString());
          }

          return Equals(properValue, xamlValue);
      }
  }