...

23 files changed, 313 insertions, 296 deletions

diff --git a/demos/main/main.cpp b/demos/main/main.cpp
index cb07d25e..c98b9fcc 100644
--- a/demos/main/main.cpp
+++ b/demos/main/main.cpp
@@ -11,7 +11,7 @@
 #include "cru/ui/controls/TextBlock.hpp"
 #include "cru/ui/controls/TextBox.hpp"
 #include "cru/ui/controls/Window.hpp"
-#include "cru/ui/events/UiEvent.hpp"
+#include "cru/ui/events/UiEvents.hpp"
 #include "cru/ui/host/WindowHost.hpp"
 
 using cru::platform::gui::IUiApplication;
@@ -50,7 +50,7 @@ int main() {
   popup_menu->GetMenu()->AddTextItem(u"Item 2000", [] {});
 
   window->MouseDownEvent()->Bubble()->AddHandler(
-      [window, &popup_menu](cru::ui::event::MouseButtonEventArgs& e) {
+      [window, &popup_menu](cru::ui::events::MouseButtonEventArgs& e) {
         if (e.GetButton() == cru::ui::mouse_buttons::right) {
           popup_menu->SetPosition(e.GetPoint() + window->GetWindowHost()
                                                      ->GetNativeWindow()
diff --git a/include/cru/ui/controls/Control.hpp b/include/cru/ui/controls/Control.hpp
index c6101370..29d48f21 100644
--- a/include/cru/ui/controls/Control.hpp
+++ b/include/cru/ui/controls/Control.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #include "Base.hpp"
 
-#include "../events/UiEvent.hpp"
+#include "../events/UiEvents.hpp"
 #include "../render/Base.hpp"
 #include "cru/common/Event.hpp"
 
@@ -75,57 +75,57 @@ class Control : public Object {
   // the mouse, this event is raised as regular. But if mouse is captured by
   // another control, the control will not receive any mouse enter event. You
   // can use `IsMouseCaptured` to get more info.
-  event::RoutedEvent<event::MouseEventArgs>* MouseEnterEvent() {
+  events::RoutedEvent<events::MouseEventArgs>* MouseEnterEvent() {
     return &mouse_enter_event_;
   }
   // Raised when mouse is leave the control. Even when the control itself
   // captures the mouse, this event is raised as regular. But if mouse is
   // captured by another control, the control will not receive any mouse leave
   // event. You can use `IsMouseCaptured` to get more info.
-  event::RoutedEvent<event::MouseEventArgs>* MouseLeaveEvent() {
+  events::RoutedEvent<events::MouseEventArgs>* MouseLeaveEvent() {
     return &mouse_leave_event_;
   }
   // Raised when mouse is move in the control.
-  event::RoutedEvent<event::MouseEventArgs>* MouseMoveEvent() {
+  events::RoutedEvent<events::MouseEventArgs>* MouseMoveEvent() {
     return &mouse_move_event_;
   }
   // Raised when a mouse button is pressed in the control.
-  event::RoutedEvent<event::MouseButtonEventArgs>* MouseDownEvent() {
+  events::RoutedEvent<events::MouseButtonEventArgs>* MouseDownEvent() {
     return &mouse_down_event_;
   }
   // Raised when a mouse button is released in the control.
-  event::RoutedEvent<event::MouseButtonEventArgs>* MouseUpEvent() {
+  events::RoutedEvent<events::MouseButtonEventArgs>* MouseUpEvent() {
     return &mouse_up_event_;
   }
-  event::RoutedEvent<event::MouseWheelEventArgs>* MouseWheelEvent() {
+  events::RoutedEvent<events::MouseWheelEventArgs>* MouseWheelEvent() {
     return &mouse_wheel_event_;
   }
-  event::RoutedEvent<event::KeyEventArgs>* KeyDownEvent() {
+  events::RoutedEvent<events::KeyEventArgs>* KeyDownEvent() {
     return &key_down_event_;
   }
-  event::RoutedEvent<event::KeyEventArgs>* KeyUpEvent() {
+  events::RoutedEvent<events::KeyEventArgs>* KeyUpEvent() {
     return &key_up_event_;
   }
-  event::RoutedEvent<event::FocusChangeEventArgs>* GainFocusEvent() {
+  events::RoutedEvent<events::FocusChangeEventArgs>* GainFocusEvent() {
     return &gain_focus_event_;
   }
-  event::RoutedEvent<event::FocusChangeEventArgs>* LoseFocusEvent() {
+  events::RoutedEvent<events::FocusChangeEventArgs>* LoseFocusEvent() {
     return &lose_focus_event_;
   }
 
  private:
-  event::RoutedEvent<event::MouseEventArgs> mouse_enter_event_;
-  event::RoutedEvent<event::MouseEventArgs> mouse_leave_event_;
-  event::RoutedEvent<event::MouseEventArgs> mouse_move_event_;
-  event::RoutedEvent<event::MouseButtonEventArgs> mouse_down_event_;
-  event::RoutedEvent<event::MouseButtonEventArgs> mouse_up_event_;
-  event::RoutedEvent<event::MouseWheelEventArgs> mouse_wheel_event_;
-
-  event::RoutedEvent<event::KeyEventArgs> key_down_event_;
-  event::RoutedEvent<event::KeyEventArgs> key_up_event_;
-
-  event::RoutedEvent<event::FocusChangeEventArgs> gain_focus_event_;
-  event::RoutedEvent<event::FocusChangeEventArgs> lose_focus_event_;
+  events::RoutedEvent<events::MouseEventArgs> mouse_enter_event_;
+  events::RoutedEvent<events::MouseEventArgs> mouse_leave_event_;
+  events::RoutedEvent<events::MouseEventArgs> mouse_move_event_;
+  events::RoutedEvent<events::MouseButtonEventArgs> mouse_down_event_;
+  events::RoutedEvent<events::MouseButtonEventArgs> mouse_up_event_;
+  events::RoutedEvent<events::MouseWheelEventArgs> mouse_wheel_event_;
+
+  events::RoutedEvent<events::KeyEventArgs> key_down_event_;
+  events::RoutedEvent<events::KeyEventArgs> key_up_event_;
+
+  events::RoutedEvent<events::FocusChangeEventArgs> gain_focus_event_;
+  events::RoutedEvent<events::FocusChangeEventArgs> lose_focus_event_;
 
   //*************** region: tree ***************
  protected:
diff --git a/include/cru/ui/controls/TextHostControlService.hpp b/include/cru/ui/controls/TextHostControlService.hpp
index 93b74d09..1bdf0509 100644
--- a/include/cru/ui/controls/TextHostControlService.hpp
+++ b/include/cru/ui/controls/TextHostControlService.hpp
@@ -161,18 +161,18 @@ class TextHostControlService : public Object {
   void UpdateInputMethodPosition();
 
   template <typename TArgs>
-  void SetupOneHandler(event::RoutedEvent<TArgs>* (Control::*event)(),
+  void SetupOneHandler(events::RoutedEvent<TArgs>* (Control::*event)(),
                        void (TextHostControlService::*handler)(
-                           typename event::RoutedEvent<TArgs>::EventArgs)) {
+                           typename events::RoutedEvent<TArgs>::EventArgs)) {
     this->event_guard_ += (this->control_->*event)()->Bubble()->AddHandler(
         std::bind(handler, this, std::placeholders::_1));
   }
 
-  void MouseMoveHandler(event::MouseEventArgs& args);
-  void MouseDownHandler(event::MouseButtonEventArgs& args);
-  void MouseUpHandler(event::MouseButtonEventArgs& args);
-  void GainFocusHandler(event::FocusChangeEventArgs& args);
-  void LoseFocusHandler(event::FocusChangeEventArgs& args);
+  void MouseMoveHandler(events::MouseEventArgs& args);
+  void MouseDownHandler(events::MouseButtonEventArgs& args);
+  void MouseUpHandler(events::MouseButtonEventArgs& args);
+  void GainFocusHandler(events::FocusChangeEventArgs& args);
+  void LoseFocusHandler(events::FocusChangeEventArgs& args);
 
   void SetUpShortcuts();
 
diff --git a/include/cru/ui/events/FocusChangeEventArgs.hpp b/include/cru/ui/events/FocusChangeEventArgs.hpp
new file mode 100644
index 00000000..0e65c6e0
--- /dev/null
+++ b/include/cru/ui/events/FocusChangeEventArgs.hpp
@@ -0,0 +1,23 @@
+#pragma once
+#include "UiEventArgs.hpp"
+
+namespace cru::ui::events {
+
+class FocusChangeEventArgs : public UiEventArgs {
+ public:
+  FocusChangeEventArgs(Object* sender, Object* original_sender,
+                       const bool is_window = false)
+      : UiEventArgs(sender, original_sender), is_window_(is_window) {}
+  FocusChangeEventArgs(const FocusChangeEventArgs& other) = default;
+  FocusChangeEventArgs(FocusChangeEventArgs&& other) = default;
+  FocusChangeEventArgs& operator=(const FocusChangeEventArgs& other) = default;
+  FocusChangeEventArgs& operator=(FocusChangeEventArgs&& other) = default;
+  ~FocusChangeEventArgs() override = default;
+
+  // Return whether the focus change is caused by the window-wide focus change.
+  bool IsWindow() const { return is_window_; }
+
+ private:
+  bool is_window_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/KeyEventArgs.hpp b/include/cru/ui/events/KeyEventArgs.hpp
new file mode 100644
index 00000000..e402dd07
--- /dev/null
+++ b/include/cru/ui/events/KeyEventArgs.hpp
@@ -0,0 +1,29 @@
+#pragma once
+#include "UiEventArgs.hpp"
+
+#include "cru/platform/gui/Keyboard.hpp"
+
+namespace cru::ui::events {
+class KeyEventArgs : public UiEventArgs {
+ public:
+  KeyEventArgs(Object* sender, Object* original_sender,
+               platform::gui::KeyCode key_code,
+               platform::gui::KeyModifier key_modifier)
+      : UiEventArgs(sender, original_sender),
+        key_code_(key_code),
+        key_modifier_(key_modifier) {}
+  KeyEventArgs(const KeyEventArgs& other) = default;
+  KeyEventArgs(KeyEventArgs&& other) = default;
+  KeyEventArgs& operator=(const KeyEventArgs& other) = default;
+  KeyEventArgs& operator=(KeyEventArgs&& other) = default;
+  ~KeyEventArgs() override = default;
+
+  platform::gui::KeyCode GetKeyCode() const { return key_code_; }
+  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
+
+ private:
+  platform::gui::KeyCode key_code_;
+  platform::gui::KeyModifier key_modifier_;
+};
+
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/MouseButtonEventArgs.hpp b/include/cru/ui/events/MouseButtonEventArgs.hpp
new file mode 100644
index 00000000..179ce8c8
--- /dev/null
+++ b/include/cru/ui/events/MouseButtonEventArgs.hpp
@@ -0,0 +1,35 @@
+#pragma once
+#include "MouseEventArgs.hpp"
+
+#include "cru/platform/gui/Keyboard.hpp"
+
+namespace cru::ui::events {
+
+class MouseButtonEventArgs : public MouseEventArgs {
+ public:
+  MouseButtonEventArgs(Object* sender, Object* original_sender,
+                       const Point& point, const MouseButton button,
+                       platform::gui::KeyModifier key_modifier)
+      : MouseEventArgs(sender, original_sender, point),
+        button_(button),
+        key_modifier_(key_modifier) {}
+  MouseButtonEventArgs(Object* sender, Object* original_sender,
+                       const MouseButton button,
+                       platform::gui::KeyModifier key_modifier)
+      : MouseEventArgs(sender, original_sender),
+        button_(button),
+        key_modifier_(key_modifier) {}
+  MouseButtonEventArgs(const MouseButtonEventArgs& other) = default;
+  MouseButtonEventArgs(MouseButtonEventArgs&& other) = default;
+  MouseButtonEventArgs& operator=(const MouseButtonEventArgs& other) = default;
+  MouseButtonEventArgs& operator=(MouseButtonEventArgs&& other) = default;
+  ~MouseButtonEventArgs() override = default;
+
+  MouseButton GetButton() const { return button_; }
+  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
+
+ private:
+  MouseButton button_;
+  platform::gui::KeyModifier key_modifier_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/MouseEventArgs.hpp b/include/cru/ui/events/MouseEventArgs.hpp
new file mode 100644
index 00000000..6d6aba15
--- /dev/null
+++ b/include/cru/ui/events/MouseEventArgs.hpp
@@ -0,0 +1,26 @@
+#pragma once
+#include "UiEventArgs.hpp"
+
+#include <optional>
+
+namespace cru::ui::events {
+class MouseEventArgs : public UiEventArgs {
+ public:
+  MouseEventArgs(Object* sender, Object* original_sender,
+                 const std::optional<Point>& point = std::nullopt)
+      : UiEventArgs(sender, original_sender), point_(point) {}
+  MouseEventArgs(const MouseEventArgs& other) = default;
+  MouseEventArgs(MouseEventArgs&& other) = default;
+  MouseEventArgs& operator=(const MouseEventArgs& other) = default;
+  MouseEventArgs& operator=(MouseEventArgs&& other) = default;
+  ~MouseEventArgs() override = default;
+
+  // This point is relative to window client lefttop.
+  Point GetPoint() const { return point_.value_or(Point{}); }
+  Point GetPoint(render::RenderObject* render_target) const;
+  Point GetPointToContent(render::RenderObject* render_target) const;
+
+ private:
+  std::optional<Point> point_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/MouseWheelEventArgs.hpp b/include/cru/ui/events/MouseWheelEventArgs.hpp
new file mode 100644
index 00000000..d0b3a145
--- /dev/null
+++ b/include/cru/ui/events/MouseWheelEventArgs.hpp
@@ -0,0 +1,29 @@
+#pragma once
+#include "MouseEventArgs.hpp"
+
+#include "cru/platform/gui/Keyboard.hpp"
+
+namespace cru::ui::events {
+class MouseWheelEventArgs : public MouseEventArgs {
+ public:
+  MouseWheelEventArgs(Object* sender, Object* original_sender,
+                      const Point& point, const float delta,
+                      platform::gui::KeyModifier key_modifier)
+      : MouseEventArgs(sender, original_sender, point),
+        delta_(delta),
+        key_modifier_(key_modifier) {}
+  MouseWheelEventArgs(const MouseWheelEventArgs& other) = default;
+  MouseWheelEventArgs(MouseWheelEventArgs&& other) = default;
+  MouseWheelEventArgs& operator=(const MouseWheelEventArgs& other) = default;
+  MouseWheelEventArgs& operator=(MouseWheelEventArgs&& other) = default;
+  ~MouseWheelEventArgs() override = default;
+
+  // Positive means down; Negative means up.
+  float GetDelta() const { return delta_; }
+  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
+
+ private:
+  float delta_;
+  platform::gui::KeyModifier key_modifier_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/PaintEventArgs.hpp b/include/cru/ui/events/PaintEventArgs.hpp
new file mode 100644
index 00000000..8bcb1590
--- /dev/null
+++ b/include/cru/ui/events/PaintEventArgs.hpp
@@ -0,0 +1,25 @@
+#pragma once
+#include "UiEventArgs.hpp"
+
+namespace cru::platform::graphics {
+struct IPainter;
+}
+
+namespace cru::ui::events {
+class PaintEventArgs : public UiEventArgs {
+ public:
+  PaintEventArgs(Object* sender, Object* original_sender,
+                 platform::graphics::IPainter* painter)
+      : UiEventArgs(sender, original_sender), painter_(painter) {}
+  PaintEventArgs(const PaintEventArgs& other) = default;
+  PaintEventArgs(PaintEventArgs&& other) = default;
+  PaintEventArgs& operator=(const PaintEventArgs& other) = default;
+  PaintEventArgs& operator=(PaintEventArgs&& other) = default;
+  ~PaintEventArgs() = default;
+
+  platform::graphics::IPainter* GetPainter() const { return painter_; }
+
+ private:
+  platform::graphics::IPainter* painter_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/RoutedEvent.hpp b/include/cru/ui/events/RoutedEvent.hpp
new file mode 100644
index 00000000..0cedc671
--- /dev/null
+++ b/include/cru/ui/events/RoutedEvent.hpp
@@ -0,0 +1,39 @@
+#pragma once
+#include "UiEventArgs.hpp"
+
+#include "cru/common/Event.hpp"
+
+namespace cru::ui::events {
+// TEventArgs must not be a reference type. This class help add reference.
+// EventArgs must be reference because the IsHandled property must be settable.
+template <typename TEventArgs>
+class RoutedEvent {
+ public:
+  static_assert(std::is_base_of_v<UiEventArgs, TEventArgs>,
+                "TEventArgs must be subclass of UiEventArgs.");
+  static_assert(!std::is_reference_v<TEventArgs>,
+                "TEventArgs must not be reference.");
+
+  using RawEventArgs = TEventArgs;
+  using IEventType = IEvent<TEventArgs&>;
+  using EventArgs = typename IEventType::EventArgs;
+
+  RoutedEvent() = default;
+  RoutedEvent(const RoutedEvent& other) = delete;
+  RoutedEvent(RoutedEvent&& other) = delete;
+  RoutedEvent& operator=(const RoutedEvent& other) = delete;
+  RoutedEvent& operator=(RoutedEvent&& other) = delete;
+  ~RoutedEvent() = default;
+
+  IEvent<TEventArgs&>* Direct() { return &direct_; }
+
+  IEvent<TEventArgs&>* Bubble() { return &bubble_; }
+
+  IEvent<TEventArgs&>* Tunnel() { return &tunnel_; }
+
+ private:
+  Event<TEventArgs&> direct_;
+  Event<TEventArgs&> bubble_;
+  Event<TEventArgs&> tunnel_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/UiEvent.hpp b/include/cru/ui/events/UiEvent.hpp
deleted file mode 100644
index 33bc0a60..00000000
--- a/include/cru/ui/events/UiEvent.hpp
+++ /dev/null
@@ -1,235 +0,0 @@
-#pragma once
-#include "../Base.hpp"
-
-#include "cru/common/Event.hpp"
-#include "cru/platform/gui/Keyboard.hpp"
-
-#include <memory>
-#include <optional>
-#include <string>
-#include <type_traits>
-
-namespace cru::platform::graphics {
-struct IPainter;
-}
-
-namespace cru::ui::event {
-class UiEventArgs : public Object {
- public:
-  UiEventArgs(Object* sender, Object* original_sender)
-      : sender_(sender), original_sender_(original_sender), handled_(false) {}
-
-  UiEventArgs(const UiEventArgs& other) = default;
-  UiEventArgs(UiEventArgs&& other) = default;
-  UiEventArgs& operator=(const UiEventArgs& other) = default;
-  UiEventArgs& operator=(UiEventArgs&& other) = default;
-  ~UiEventArgs() override = default;
-
-  Object* GetSender() const { return sender_; }
-
-  Object* GetOriginalSender() const { return original_sender_; }
-
-  bool IsHandled() const { return handled_; }
-  void SetHandled(const bool handled = true) { handled_ = handled; }
-
- private:
-  Object* sender_;
-  Object* original_sender_;
-  bool handled_;
-};
-
-// TEventArgs must not be a reference type. This class help add reference.
-// EventArgs must be reference because the IsHandled property must be settable.
-template <typename TEventArgs>
-class RoutedEvent {
- public:
-  static_assert(std::is_base_of_v<UiEventArgs, TEventArgs>,
-                "TEventArgs must be subclass of UiEventArgs.");
-  static_assert(!std::is_reference_v<TEventArgs>,
-                "TEventArgs must not be reference.");
-
-  using RawEventArgs = TEventArgs;
-  using IEventType = IEvent<TEventArgs&>;
-  using EventArgs = typename IEventType::EventArgs;
-
-  RoutedEvent() = default;
-  RoutedEvent(const RoutedEvent& other) = delete;
-  RoutedEvent(RoutedEvent&& other) = delete;
-  RoutedEvent& operator=(const RoutedEvent& other) = delete;
-  RoutedEvent& operator=(RoutedEvent&& other) = delete;
-  ~RoutedEvent() = default;
-
-  IEvent<TEventArgs&>* Direct() { return &direct_; }
-
-  IEvent<TEventArgs&>* Bubble() { return &bubble_; }
-
-  IEvent<TEventArgs&>* Tunnel() { return &tunnel_; }
-
- private:
-  Event<TEventArgs&> direct_;
-  Event<TEventArgs&> bubble_;
-  Event<TEventArgs&> tunnel_;
-};
-
-class MouseEventArgs : public UiEventArgs {
- public:
-  MouseEventArgs(Object* sender, Object* original_sender,
-                 const std::optional<Point>& point = std::nullopt)
-      : UiEventArgs(sender, original_sender), point_(point) {}
-  MouseEventArgs(const MouseEventArgs& other) = default;
-  MouseEventArgs(MouseEventArgs&& other) = default;
-  MouseEventArgs& operator=(const MouseEventArgs& other) = default;
-  MouseEventArgs& operator=(MouseEventArgs&& other) = default;
-  ~MouseEventArgs() override = default;
-
-  // This point is relative to window client lefttop.
-  Point GetPoint() const { return point_.value_or(Point{}); }
-  Point GetPoint(render::RenderObject* render_target) const;
-  Point GetPointToContent(render::RenderObject* render_target) const;
-
- private:
-  std::optional<Point> point_;
-};
-
-class MouseButtonEventArgs : public MouseEventArgs {
- public:
-  MouseButtonEventArgs(Object* sender, Object* original_sender,
-                       const Point& point, const MouseButton button,
-                       platform::gui::KeyModifier key_modifier)
-      : MouseEventArgs(sender, original_sender, point),
-        button_(button),
-        key_modifier_(key_modifier) {}
-  MouseButtonEventArgs(Object* sender, Object* original_sender,
-                       const MouseButton button,
-                       platform::gui::KeyModifier key_modifier)
-      : MouseEventArgs(sender, original_sender),
-        button_(button),
-        key_modifier_(key_modifier) {}
-  MouseButtonEventArgs(const MouseButtonEventArgs& other) = default;
-  MouseButtonEventArgs(MouseButtonEventArgs&& other) = default;
-  MouseButtonEventArgs& operator=(const MouseButtonEventArgs& other) = default;
-  MouseButtonEventArgs& operator=(MouseButtonEventArgs&& other) = default;
-  ~MouseButtonEventArgs() override = default;
-
-  MouseButton GetButton() const { return button_; }
-  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
-
- private:
-  MouseButton button_;
-  platform::gui::KeyModifier key_modifier_;
-};
-
-class MouseWheelEventArgs : public MouseEventArgs {
- public:
-  MouseWheelEventArgs(Object* sender, Object* original_sender,
-                      const Point& point, const float delta,
-                      platform::gui::KeyModifier key_modifier)
-      : MouseEventArgs(sender, original_sender, point),
-        delta_(delta),
-        key_modifier_(key_modifier) {}
-  MouseWheelEventArgs(const MouseWheelEventArgs& other) = default;
-  MouseWheelEventArgs(MouseWheelEventArgs&& other) = default;
-  MouseWheelEventArgs& operator=(const MouseWheelEventArgs& other) = default;
-  MouseWheelEventArgs& operator=(MouseWheelEventArgs&& other) = default;
-  ~MouseWheelEventArgs() override = default;
-
-  // Positive means down; Negative means up.
-  float GetDelta() const { return delta_; }
-  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
-
- private:
-  float delta_;
-  platform::gui::KeyModifier key_modifier_;
-};
-
-class PaintEventArgs : public UiEventArgs {
- public:
-  PaintEventArgs(Object* sender, Object* original_sender,
-                 platform::graphics::IPainter* painter)
-      : UiEventArgs(sender, original_sender), painter_(painter) {}
-  PaintEventArgs(const PaintEventArgs& other) = default;
-  PaintEventArgs(PaintEventArgs&& other) = default;
-  PaintEventArgs& operator=(const PaintEventArgs& other) = default;
-  PaintEventArgs& operator=(PaintEventArgs&& other) = default;
-  ~PaintEventArgs() = default;
-
-  platform::graphics::IPainter* GetPainter() const { return painter_; }
-
- private:
-  platform::graphics::IPainter* painter_;
-};
-
-class FocusChangeEventArgs : public UiEventArgs {
- public:
-  FocusChangeEventArgs(Object* sender, Object* original_sender,
-                       const bool is_window = false)
-      : UiEventArgs(sender, original_sender), is_window_(is_window) {}
-  FocusChangeEventArgs(const FocusChangeEventArgs& other) = default;
-  FocusChangeEventArgs(FocusChangeEventArgs&& other) = default;
-  FocusChangeEventArgs& operator=(const FocusChangeEventArgs& other) = default;
-  FocusChangeEventArgs& operator=(FocusChangeEventArgs&& other) = default;
-  ~FocusChangeEventArgs() override = default;
-
-  // Return whether the focus change is caused by the window-wide focus change.
-  bool IsWindow() const { return is_window_; }
-
- private:
-  bool is_window_;
-};
-
-/*
-class ToggleEventArgs : public UiEventArgs {
- public:
-  ToggleEventArgs(Object* sender, Object* original_sender, bool new_state)
-      : UiEventArgs(sender, original_sender), new_state_(new_state) {}
-  ToggleEventArgs(const ToggleEventArgs& other) = default;
-  ToggleEventArgs(ToggleEventArgs&& other) = default;
-  ToggleEventArgs& operator=(const ToggleEventArgs& other) = default;
-  ToggleEventArgs& operator=(ToggleEventArgs&& other) = default;
-  ~ToggleEventArgs() override = default;
-
-  bool GetNewState() const { return new_state_; }
-
- private:
-  bool new_state_;
-};
-*/
-
-class KeyEventArgs : public UiEventArgs {
- public:
-  KeyEventArgs(Object* sender, Object* original_sender,
-               platform::gui::KeyCode key_code,
-               platform::gui::KeyModifier key_modifier)
-      : UiEventArgs(sender, original_sender),
-        key_code_(key_code),
-        key_modifier_(key_modifier) {}
-  KeyEventArgs(const KeyEventArgs& other) = default;
-  KeyEventArgs(KeyEventArgs&& other) = default;
-  KeyEventArgs& operator=(const KeyEventArgs& other) = default;
-  KeyEventArgs& operator=(KeyEventArgs&& other) = default;
-  ~KeyEventArgs() override = default;
-
-  platform::gui::KeyCode GetKeyCode() const { return key_code_; }
-  platform::gui::KeyModifier GetKeyModifier() const { return key_modifier_; }
-
- private:
-  platform::gui::KeyCode key_code_;
-  platform::gui::KeyModifier key_modifier_;
-};
-
-class CharEventArgs : public UiEventArgs {
- public:
-  CharEventArgs(Object* sender, Object* original_sender, std::u16string c)
-      : UiEventArgs(sender, original_sender), c_(std::move(c)) {}
-  CharEventArgs(const CharEventArgs& other) = default;
-  CharEventArgs(CharEventArgs&& other) = default;
-  CharEventArgs& operator=(const CharEventArgs& other) = default;
-  CharEventArgs& operator=(CharEventArgs&& other) = default;
-  ~CharEventArgs() override = default;
-
-  std::u16string GetChar() const { return c_; }
-
- private:
-  std::u16string c_;
-};
-}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/UiEventArgs.hpp b/include/cru/ui/events/UiEventArgs.hpp
new file mode 100644
index 00000000..d1b44940
--- /dev/null
+++ b/include/cru/ui/events/UiEventArgs.hpp
@@ -0,0 +1,28 @@
+#pragma once
+#include "../Base.hpp"
+
+namespace cru::ui::events {
+class UiEventArgs : public Object {
+ public:
+  UiEventArgs(Object* sender, Object* original_sender)
+      : sender_(sender), original_sender_(original_sender), handled_(false) {}
+
+  UiEventArgs(const UiEventArgs& other) = default;
+  UiEventArgs(UiEventArgs&& other) = default;
+  UiEventArgs& operator=(const UiEventArgs& other) = default;
+  UiEventArgs& operator=(UiEventArgs&& other) = default;
+  ~UiEventArgs() override = default;
+
+  Object* GetSender() const { return sender_; }
+
+  Object* GetOriginalSender() const { return original_sender_; }
+
+  bool IsHandled() const { return handled_; }
+  void SetHandled(const bool handled = true) { handled_ = handled; }
+
+ private:
+  Object* sender_;
+  Object* original_sender_;
+  bool handled_;
+};
+}  // namespace cru::ui::event
diff --git a/include/cru/ui/events/UiEvents.hpp b/include/cru/ui/events/UiEvents.hpp
new file mode 100644
index 00000000..bd6f7d2a
--- /dev/null
+++ b/include/cru/ui/events/UiEvents.hpp
@@ -0,0 +1,10 @@
+#pragma once
+
+#include "FocusChangeEventArgs.hpp"
+#include "KeyEventArgs.hpp"
+#include "MouseButtonEventArgs.hpp"
+#include "MouseEventArgs.hpp"
+#include "MouseWheelEventArgs.hpp"
+#include "PaintEventArgs.hpp"
+#include "RoutedEvent.hpp"
+#include "UiEventArgs.hpp"
diff --git a/include/cru/ui/helper/ShortcutHub.hpp b/include/cru/ui/helper/ShortcutHub.hpp
index 5b9612ba..def024a8 100644
--- a/include/cru/ui/helper/ShortcutHub.hpp
+++ b/include/cru/ui/helper/ShortcutHub.hpp
@@ -1,7 +1,7 @@
 #pragma once
 #include "../Base.hpp"
 
-#include "../events/UiEvent.hpp"
+#include "../events/UiEvents.hpp"
 #include "cru/common/Event.hpp"
 #include "cru/platform/gui/Keyboard.hpp"
 
@@ -120,13 +120,13 @@ class ShortcutHub : public Object {
   const std::vector<ShortcutInfo>& GetShortcutByKeyBind(
       const ShortcutKeyBind& key_bind) const;
 
-  IEvent<event::KeyEventArgs&>* FallbackKeyEvent() { return &fallback_event_; }
+  IEvent<events::KeyEventArgs&>* FallbackKeyEvent() { return &fallback_event_; }
 
   void Install(controls::Control* control);
   void Uninstall();
 
  private:
-  void OnKeyDown(event::KeyEventArgs& event);
+  void OnKeyDown(events::KeyEventArgs& event);
 
  private:
   std::unordered_map<ShortcutKeyBind, std::vector<ShortcutInfo>> map_;
@@ -135,7 +135,7 @@ class ShortcutHub : public Object {
 
   int current_id_ = 1;
 
-  Event<event::KeyEventArgs&> fallback_event_;
+  Event<events::KeyEventArgs&> fallback_event_;
 
   EventRevokerListGuard event_guard_;
 };
diff --git a/src/ui/CMakeLists.txt b/src/ui/CMakeLists.txt
index 35c3581f..e4707cbc 100644
--- a/src/ui/CMakeLists.txt
+++ b/src/ui/CMakeLists.txt
@@ -24,7 +24,7 @@ add_library(cru_ui STATIC
 	controls/TextBox.cpp
 	controls/TextHostControlService.cpp
 	controls/Window.cpp
-	events/UiEvent.cpp
+	events/MouseEventArgs.cpp
 	helper/ClickDetector.cpp
 	helper/ShortcutHub.cpp
 	host/LayoutPaintCycler.cpp
@@ -68,7 +68,15 @@ target_sources(cru_ui PUBLIC
 	${CRU_UI_INCLUDE_DIR}/controls/TextBox.hpp
 	${CRU_UI_INCLUDE_DIR}/controls/TextHostControlService.hpp
 	${CRU_UI_INCLUDE_DIR}/controls/Window.hpp
-	${CRU_UI_INCLUDE_DIR}/events/UiEvent.hpp
+	${CRU_UI_INCLUDE_DIR}/events/FocusChangeEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/KeyEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/MouseButtonEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/MouseEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/MouseWheelEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/PaintEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/RoutedEvent.hpp
+	${CRU_UI_INCLUDE_DIR}/events/UiEventArgs.hpp
+	${CRU_UI_INCLUDE_DIR}/events/UiEvents.hpp
 	${CRU_UI_INCLUDE_DIR}/helper/ClickDetector.hpp
 	${CRU_UI_INCLUDE_DIR}/helper/ShortcutHub.hpp
 	${CRU_UI_INCLUDE_DIR}/host/LayoutPaintCycler.hpp
diff --git a/src/ui/controls/Control.cpp b/src/ui/controls/Control.cpp
index 29c2c46a..44da7f6f 100644
--- a/src/ui/controls/Control.cpp
+++ b/src/ui/controls/Control.cpp
@@ -20,12 +20,12 @@ Control::Control() {
   style_rule_set_bind_ =
       std::make_unique<style::StyleRuleSetBind>(this, style_rule_set_.get());
 
-  MouseEnterEvent()->Direct()->AddHandler([this](event::MouseEventArgs&) {
+  MouseEnterEvent()->Direct()->AddHandler([this](events::MouseEventArgs&) {
     this->is_mouse_over_ = true;
     this->OnMouseHoverChange(true);
   });
 
-  MouseLeaveEvent()->Direct()->AddHandler([this](event::MouseEventArgs&) {
+  MouseLeaveEvent()->Direct()->AddHandler([this](events::MouseEventArgs&) {
     this->is_mouse_over_ = false;
     this->OnMouseHoverChange(true);
   });
diff --git a/src/ui/controls/TextHostControlService.cpp b/src/ui/controls/TextHostControlService.cpp
index b0759058..3a67860d 100644
--- a/src/ui/controls/TextHostControlService.cpp
+++ b/src/ui/controls/TextHostControlService.cpp
@@ -15,7 +15,7 @@
 #include "cru/ui/Base.hpp"
 #include "cru/ui/DebugFlags.hpp"
 #include "cru/ui/components/Menu.hpp"
-#include "cru/ui/events/UiEvent.hpp"
+#include "cru/ui/events/UiEvents.hpp"
 #include "cru/ui/helper/ShortcutHub.hpp"
 #include "cru/ui/host/WindowHost.hpp"
 #include "cru/ui/render/ScrollRenderObject.hpp"
@@ -445,7 +445,7 @@ void TextHostControlService::UpdateInputMethodPosition() {
 }
 
 void TextHostControlService::MouseDownHandler(
-    event::MouseButtonEventArgs& args) {
+    events::MouseButtonEventArgs& args) {
   if (IsEnabled()) {
     this->control_->SetFocus();
     if (args.GetButton() == mouse_buttons::left &&
@@ -461,14 +461,14 @@ void TextHostControlService::MouseDownHandler(
   }
 }
 
-void TextHostControlService::MouseUpHandler(event::MouseButtonEventArgs& args) {
+void TextHostControlService::MouseUpHandler(events::MouseButtonEventArgs& args) {
   if (args.GetButton() == mouse_buttons::left && mouse_move_selecting_) {
     this->control_->ReleaseMouse();
     this->mouse_move_selecting_ = false;
   }
 }
 
-void TextHostControlService::MouseMoveHandler(event::MouseEventArgs& args) {
+void TextHostControlService::MouseMoveHandler(events::MouseEventArgs& args) {
   if (this->mouse_move_selecting_) {
     const auto text_render_object = this->GetTextRenderObject();
     const auto result = text_render_object->TextHitTest(
@@ -479,7 +479,7 @@ void TextHostControlService::MouseMoveHandler(event::MouseEventArgs& args) {
 }
 
 void TextHostControlService::GainFocusHandler(
-    event::FocusChangeEventArgs& args) {
+    events::FocusChangeEventArgs& args) {
   CRU_UNUSED(args);
   if (editable_) {
     auto input_method_context = GetInputMethodContext();
@@ -514,7 +514,7 @@ void TextHostControlService::GainFocusHandler(
 }
 
 void TextHostControlService::LoseFocusHandler(
-    event::FocusChangeEventArgs& args) {
+    events::FocusChangeEventArgs& args) {
   if (!args.IsWindow()) this->AbortSelection();
   input_method_context_event_guard_.Clear();
   auto input_method_context = GetInputMethodContext();
diff --git a/src/ui/events/UiEvent.cpp b/src/ui/events/MouseEventArgs.cpp
index 4c75f690..b27bb9d4 100644
--- a/src/ui/events/UiEvent.cpp
+++ b/src/ui/events/MouseEventArgs.cpp
@@ -1,8 +1,8 @@
-#include "cru/ui/events/UiEvent.hpp"
+#include "cru/ui/events/MouseEventArgs.hpp"
 
 #include "cru/ui/render/RenderObject.hpp"
 
-namespace cru::ui::event {
+namespace cru::ui::events {
 Point MouseEventArgs::GetPoint(render::RenderObject* render_object) const {
   return GetPoint() - render_object->GetTotalOffset();
 }
@@ -11,4 +11,4 @@ Point MouseEventArgs::GetPointToContent(
     render::RenderObject* render_object) const {
   return render_object->FromRootToContent(GetPoint());
 }
-}  // namespace cru::ui::event
+}  // namespace cru::ui::events
diff --git a/src/ui/helper/ClickDetector.cpp b/src/ui/helper/ClickDetector.cpp
index 309685d3..d8d51327 100644
--- a/src/ui/helper/ClickDetector.cpp
+++ b/src/ui/helper/ClickDetector.cpp
@@ -12,7 +12,7 @@ ClickDetector::ClickDetector(controls::Control* control) {
 
   event_rovoker_guards_.push_back(
       EventRevokerGuard(control->MouseEnterEvent()->Direct()->AddHandler(
-          [this](event::MouseEventArgs&) {
+          [this](events::MouseEventArgs&) {
             if (this->enable_) {
               if (this->state_ == ClickState::PressInactive) {
                 if ((this->button_ & this->trigger_button_)) {
@@ -26,7 +26,7 @@ ClickDetector::ClickDetector(controls::Control* control) {
 
   event_rovoker_guards_.push_back(
       EventRevokerGuard(control->MouseLeaveEvent()->Direct()->AddHandler(
-          [this](event::MouseEventArgs&) {
+          [this](events::MouseEventArgs&) {
             if (this->enable_) {
               if (this->state_ == ClickState::Press) {
                 if ((this->button_ & this->trigger_button_)) {
@@ -40,7 +40,7 @@ ClickDetector::ClickDetector(controls::Control* control) {
 
   event_rovoker_guards_.push_back(
       EventRevokerGuard(control->MouseDownEvent()->Direct()->AddHandler(
-          [this](event::MouseButtonEventArgs& args) {
+          [this](events::MouseButtonEventArgs& args) {
             const auto button = args.GetButton();
             if (this->enable_ && (button & this->trigger_button_) &&
                 this->state_ == ClickState::Hover) {
@@ -59,7 +59,7 @@ ClickDetector::ClickDetector(controls::Control* control) {
 
   event_rovoker_guards_.push_back(
       EventRevokerGuard(control->MouseUpEvent()->Direct()->AddHandler(
-          [this](event::MouseButtonEventArgs& args) {
+          [this](events::MouseButtonEventArgs& args) {
             const auto button = args.GetButton();
             if (this->enable_ && (button & this->trigger_button_) &&
                 button == button_) {
diff --git a/src/ui/helper/ShortcutHub.cpp b/src/ui/helper/ShortcutHub.cpp
index f35ad0ef..c0b6c5d8 100644
--- a/src/ui/helper/ShortcutHub.cpp
+++ b/src/ui/helper/ShortcutHub.cpp
@@ -81,7 +81,7 @@ void ShortcutHub::Uninstall() {
   event_guard_.Clear();
 }
 
-void ShortcutHub::OnKeyDown(event::KeyEventArgs& event) {
+void ShortcutHub::OnKeyDown(events::KeyEventArgs& event) {
   ShortcutKeyBind key_bind(event.GetKeyCode(), event.GetKeyModifier());
   const auto& shortcut_list = this->GetShortcutByKeyBind(key_bind);
 
diff --git a/src/ui/host/RoutedEventDispatch.hpp b/src/ui/host/RoutedEventDispatch.hpp
index 52507fc7..027ddbe4 100644
--- a/src/ui/host/RoutedEventDispatch.hpp
+++ b/src/ui/host/RoutedEventDispatch.hpp
@@ -23,7 +23,7 @@ template <typename EventArgs, typename... Args>
 void DispatchEvent(
     const std::u16string_view& event_name,
     controls::Control* const original_sender,
-    event::RoutedEvent<EventArgs>* (controls::Control::*event_ptr)(),
+    events::RoutedEvent<EventArgs>* (controls::Control::*event_ptr)(),
     controls::Control* const last_receiver, Args&&... args) {
   CRU_UNUSED(event_name)
 
diff --git a/src/ui/render/ScrollBar.cpp b/src/ui/render/ScrollBar.cpp
index aeecd9e2..8e16862f 100644
--- a/src/ui/render/ScrollBar.cpp
+++ b/src/ui/render/ScrollBar.cpp
@@ -12,7 +12,7 @@
 #include "cru/ui/Base.hpp"
 #include "cru/ui/ThemeManager.hpp"
 #include "cru/ui/UiManager.hpp"
-#include "cru/ui/events/UiEvent.hpp"
+#include "cru/ui/events/UiEvents.hpp"
 #include "cru/ui/helper/ClickDetector.hpp"
 #include "cru/ui/host/WindowHost.hpp"
 #include "cru/ui/render/ScrollRenderObject.hpp"
@@ -124,7 +124,7 @@ void ScrollBar::InstallHandlers(controls::Control* control) {
   if (control != nullptr) {
     event_guard_ +=
         control->MouseDownEvent()->Tunnel()->PrependShortCircuitHandler(
-            [control, this](event::MouseButtonEventArgs& event) {
+            [control, this](events::MouseButtonEventArgs& event) {
               if (event.GetButton() == mouse_buttons::left && IsEnabled() &&
                   IsExpanded()) {
                 auto hit_test_result =
@@ -178,7 +178,7 @@ void ScrollBar::InstallHandlers(controls::Control* control) {
 
     event_guard_ +=
         control->MouseUpEvent()->Tunnel()->PrependShortCircuitHandler(
-            [control, this](event::MouseButtonEventArgs& event) {
+            [control, this](events::MouseButtonEventArgs& event) {
               if (mouse_press_ != std::nullopt) {
                 mouse_press_ = std::nullopt;
                 render_object_->InvalidatePaint();
@@ -203,7 +203,7 @@ void ScrollBar::InstallHandlers(controls::Control* control) {
 
     event_guard_ +=
         control->MouseMoveEvent()->Tunnel()->PrependShortCircuitHandler(
-            [this](event::MouseEventArgs& event) {
+            [this](events::MouseEventArgs& event) {
               if (move_thumb_start_) {
                 auto new_scroll_position = CalculateNewScrollPosition(
                     move_thumb_thumb_original_rect_,
@@ -249,7 +249,7 @@ void ScrollBar::InstallHandlers(controls::Control* control) {
 
     event_guard_ +=
         control->MouseLeaveEvent()->Tunnel()->PrependShortCircuitHandler(
-            [this](event::MouseEventArgs&) {
+            [this](events::MouseEventArgs&) {
               if (IsExpanded() && !move_thumb_start_) {
                 if (mouse_hover_ != std::nullopt) {
                   mouse_hover_ = std::nullopt;
diff --git a/src/ui/render/ScrollRenderObject.cpp b/src/ui/render/ScrollRenderObject.cpp
index 93472cdc..bd9b8559 100644
--- a/src/ui/render/ScrollRenderObject.cpp
+++ b/src/ui/render/ScrollRenderObject.cpp
@@ -211,7 +211,7 @@ void ScrollRenderObject::InstallMouseWheelHandler(controls::Control* control) {
 
   if (control != nullptr) {
     guard_ += control->MouseWheelEvent()->Bubble()->PrependShortCircuitHandler(
-        [this](event::MouseWheelEventArgs& args) {
+        [this](events::MouseWheelEventArgs& args) {
           auto delta = args.GetDelta();
 
           delta *= 24;