Add get_hash_code method

src/xtd.forms/include/xtd/forms/flat_button_appearance.hpp

@@ -117,8 +117,18 @@ namespace xtd {
       /// @name Public Methods
 
       /// @{
-      using object::equals;
+      /// @brief Determines whether the specified object is equal to the current object.
+      /// @param obj The object to compare with the current object.
+      /// @return `true` if the specified object is equal to the current object. otherwise, `false`.
+      bool equals(const xtd::object& obj) const noexcept override;
+      /// @brief Determines whether the specified object is equal to the current object.
+      /// @param other The object to compare with the current object.
+      /// @return `true` if the specified object is equal to the current object. otherwise, `false`.
       bool equals(const flat_button_appearance& other) const noexcept override;
+
+      /// @brief Serves as a hash function for a particular type.
+      /// @return A hash code for the current object.
+      xtd::size get_hash_code() const noexcept override;
       /// @}
 
     private:

src/xtd.forms/src/xtd/forms/flat_button_appearance.cpp

@@ -108,6 +108,14 @@ flat_button_appearance& flat_button_appearance::mouse_over_back_color(std::nullp
   return *this;
 }
 
+bool flat_button_appearance::equals(const object& obj) const noexcept {
+  return is<flat_button_appearance>(obj) && equals(static_cast<const flat_button_appearance&>(obj));
+}
+
 bool flat_button_appearance::equals(const flat_button_appearance& other) const noexcept {
-  return data_->border_color == other.data_->border_color && data_->border_size == other.data_->border_size && data_->checked_back_color == other.data_->checked_back_color && data_->mouse_down_back_color == other.data_->mouse_down_back_color && data_->mouse_over_back_color == other.data_->mouse_over_back_color;
+  return data_->border_color == other.data_->border_color && data_->border_radius == other.data_->border_radius && data_->border_size == other.data_->border_size && data_->checked_back_color == other.data_->checked_back_color && data_->mouse_down_back_color == other.data_->mouse_down_back_color && data_->mouse_over_back_color == other.data_->mouse_over_back_color;
+}
+
+xtd::size flat_button_appearance::get_hash_code() const noexcept {
+  return hash_code::combine(data_->border_color.value_or(drawing::color::empty), data_->border_radius.value_or(0), data_->border_size.value_or(0), data_->checked_back_color.value_or(drawing::color::empty), data_->mouse_down_back_color.value_or(drawing::color::empty), data_->mouse_over_back_color.value_or(drawing::color::empty));
 }