Rework hotkey registration for sharing hotkeys between objects.

Use colors for working, failing or unset hotkeys in HotkeySelector.

Business/KeyboardInput.cs

@@ -13,7 +13,7 @@ namespace SystemTrayMenu.Handler
 
     internal class KeyboardInput : IDisposable
     {
-        private GlobalHotkeys.HotkeyRegistrationHandle? hotkeyHandle;
+        private GlobalHotkeys.IHotkeyRegistration? hotkeyRegistration;
 
         private Menu? focussedMenu;
 
@@ -27,7 +27,7 @@ namespace SystemTrayMenu.Handler
 
         public void Dispose()
         {
-            GlobalHotkeys.Unregister(hotkeyHandle);
+            GlobalHotkeys.Unregister(hotkeyRegistration);
         }
 
         internal bool RegisterHotKey(string hotKeyString)
@@ -36,7 +36,7 @@ namespace SystemTrayMenu.Handler
             {
                 try
                 {
-                    hotkeyHandle = GlobalHotkeys.Register(hotKeyString);
+                    hotkeyRegistration = GlobalHotkeys.Register(hotKeyString);
                 }
                 catch (InvalidOperationException ex)
                 {
@@ -44,7 +44,7 @@ namespace SystemTrayMenu.Handler
                     return false;
                 }
 
-                hotkeyHandle.KeyPressed += (_) => HotKeyPressed?.Invoke();
+                hotkeyRegistration.KeyPressed += (_) => HotKeyPressed?.Invoke();
             }
 
             return true;

Helpers/GlobalHotkeys.cs

@@ -30,6 +30,15 @@ namespace SystemTrayMenu.Helpers
             HWnd.AddHook(Hook);
         }
 
+        internal interface IHotkeyRegistration
+        {
+            event Action<IHotkeyRegistration>? KeyPressed;
+
+            ModifierKeys GetModifierKeys();
+
+            Key GetKey();
+        }
+
         /// <summary>
         /// Registers a global hotkey.
         /// Function is thread safe.
@@ -38,8 +47,8 @@ namespace SystemTrayMenu.Helpers
         /// </summary>
         /// <param name="modifiers">Hotkey modifiers.</param>
         /// <param name="key">Hotkey major key.</param>
-        /// <returns>Handle of this registration.</returns>
-        internal static HotkeyRegistrationHandle Register(ModifierKeys modifiers, Key key)
+        /// <returns>Registration interface.</returns>
+        internal static IHotkeyRegistration Register(ModifierKeys modifiers, Key key)
         {
             int virtualKeyCode = KeyInterop.VirtualKeyFromKey(key);
             int id = 0;
@@ -61,14 +70,14 @@ namespace SystemTrayMenu.Helpers
                 }
             }
 
-            HotkeyRegistration regHandle = new()
+            HotkeyRegistration registration = new()
             {
                 Id = id,
                 Modifiers = modifiers,
                 Key = key,
             };
-            Registrations.Add(regHandle);
-            return regHandle;
+            Registrations.Add(registration);
+            return registration;
         }
 
         /// <summary>
@@ -78,8 +87,8 @@ namespace SystemTrayMenu.Helpers
         /// The caller needs to call UnregisterHotkey to free up ressources.
         /// </summary>
         /// <param name="hotKeyString">Hotkey string representation.</param>
-        /// <returns>Handle of this registration.</returns>
-        internal static HotkeyRegistrationHandle Register(string hotKeyString)
+        /// <returns>Registration interface.</returns>
+        internal static IHotkeyRegistration Register(string hotKeyString)
         {
             var (modifiers, key) = ParseKeysAndModifiersFromString(hotKeyString);
             return Register(modifiers, key);
@@ -89,11 +98,11 @@ namespace SystemTrayMenu.Helpers
         /// Unregisters a global hotkey in a thread safe manner.
         /// Function is thread safe.
         /// </summary>
-        /// <param name="regHandle">Handle of the registration.</param>
+        /// <param name="registration">Registration interface.</param>
         /// <returns>true: Success or false: Failure.</returns>
-        internal static bool Unregister(HotkeyRegistrationHandle? regHandle)
+        internal static bool Unregister(IHotkeyRegistration? registration)
         {
-            if (regHandle == null || regHandle is not HotkeyRegistration reg || Registrations.Contains(reg))
+            if (registration == null || registration is not HotkeyRegistration reg || Registrations.Contains(reg))
             {
                 return true;
             }
@@ -111,6 +120,26 @@ namespace SystemTrayMenu.Helpers
             return true;
         }
 
+        // TODO: Instead of searching for the registration, it should be passed to the caller instead.
+        //       Only this ensures caller and registrator are talking about the SAME registration.
+        internal static IHotkeyRegistration? FindRegistration(string hotKeyString)
+        {
+            var (modifiers, key) = ParseKeysAndModifiersFromString(hotKeyString);
+
+            lock (CriticalSectionLock)
+            {
+                foreach (var registration in Registrations)
+                {
+                    if (modifiers == registration.Modifiers && key == registration.Key)
+                    {
+                        return registration;
+                    }
+                }
+            }
+
+            return null;
+        }
+
         internal static ModifierKeys ModifierKeysFromString(string modifiersString)
         {
             ModifierKeys modifiers = ModifierKeys.None;
@@ -296,11 +325,11 @@ namespace SystemTrayMenu.Helpers
                 HotkeyRegistration? reg = null;
                 lock (CriticalSectionLock)
                 {
-                    foreach (var regHandle in Registrations)
+                    foreach (var registration in Registrations)
                     {
-                        if (modifiers == regHandle.Modifiers && key == regHandle.Key)
+                        if (modifiers == registration.Modifiers && key == registration.Key)
                         {
-                            reg = regHandle;
+                            reg = registration;
                             break;
                         }
                     }
@@ -313,22 +342,21 @@ namespace SystemTrayMenu.Helpers
             return IntPtr.Zero;
         }
 
-        internal abstract class HotkeyRegistrationHandle
+        private class HotkeyRegistration : IHotkeyRegistration
         {
-            internal event Action<HotkeyRegistrationHandle>? KeyPressed;
+            public event Action<IHotkeyRegistration>? KeyPressed;
 
-            protected void RiseKeyPressed() => KeyPressed?.Invoke(this);
-        }
-
-        private class HotkeyRegistration : HotkeyRegistrationHandle
-        {
             internal int Id { get; init; }
 
             internal ModifierKeys Modifiers { get; set; }
 
             internal Key Key { get; set; }
 
-            internal void OnKeyPressed() => RiseKeyPressed();
+            public ModifierKeys GetModifierKeys() => Modifiers;
+
+            public Key GetKey() => Key;
+
+            internal void OnKeyPressed() => KeyPressed?.Invoke(this);
         }
     }
 }

UserInterface/HotkeySelector.cs

@@ -9,10 +9,13 @@ namespace SystemTrayMenu.UserInterface
     using System;
     using System.Collections.Generic;
     using System.Text;
+    using System.Windows;
     using System.Windows.Controls;
     using System.Windows.Input;
+    using System.Windows.Media;
     using SystemTrayMenu.Helpers;
     using SystemTrayMenu.Utilities;
+    using static SystemTrayMenu.Helpers.GlobalHotkeys;
 
     public sealed class HotkeySelector : TextBox
     {
@@ -21,9 +24,8 @@ namespace SystemTrayMenu.UserInterface
         private readonly IList<int> needNonShiftModifier = new List<int>();
         private readonly IList<int> needNonAltGrModifier = new List<int>();
 
-        private GlobalHotkeys.HotkeyRegistrationHandle? hotkeyHandle;
-
         // These variables store the current hotkey and modifier(s)
+        private IHotkeyRegistration? hotkeyHandle;
         private Key hotkey = Key.None;
         private ModifierKeys modifiers = ModifierKeys.None;
         private Action? handler;
@@ -40,8 +42,6 @@ namespace SystemTrayMenu.UserInterface
                 IsEnabled = false,
             };
 
-            Text = string.Empty;
-
             // Handle events that occurs when keys are pressed
             KeyUp += HotkeyControl_KeyUp;
             KeyDown += HotkeyControl_KeyDown;
@@ -73,37 +73,7 @@ namespace SystemTrayMenu.UserInterface
             };
 
             PopulateModifierLists();
-        }
-
-        ~HotkeySelector()
-        {
-            GlobalHotkeys.Unregister(hotkeyHandle);
-        }
-
-        /// <summary>
-        /// Gets or sets used to get/set the hotkey (e.g. Key.A).
-        /// </summary>
-        public Key Hotkey
-        {
-            get => hotkey;
-            set
-            {
-                hotkey = value;
-                Redraw(true);
-            }
-        }
-
-        /// <summary>
-        /// Gets or sets used to get/set the modifier keys (e.g. Alt | Control).
-        /// </summary>
-        public ModifierKeys HotkeyModifiers
-        {
-            get => modifiers;
-            set
-            {
-                modifiers = value;
-                Redraw(true);
-            }
+            SetHotkeyRegistration((IHotkeyRegistration?)null);
         }
 
         internal bool Reassigning { get; private set; }
@@ -137,13 +107,43 @@ namespace SystemTrayMenu.UserInterface
         public override string ToString() => HotkeyToString(modifiers, hotkey);
 
         /// <summary>
-        /// Used to get/set the hotkey (e.g. Key.A).
+        /// Set the registration interface the control is working on.
         /// </summary>
-        /// <param name="hotkey">hotkey.</param>
-        public void SetHotkey(string hotkey)
+        /// <param name="registration">Registration interface.</param>
+        internal void SetHotkeyRegistration(IHotkeyRegistration? registration)
         {
-            this.hotkey = GlobalHotkeys.KeyFromString(hotkey);
-            modifiers = GlobalHotkeys.ModifierKeysFromString(hotkey);
+            hotkeyHandle = registration;
+            if (hotkeyHandle != null)
+            {
+                hotkey = hotkeyHandle.GetKey();
+                modifiers = hotkeyHandle.GetModifierKeys();
+                Background = Brushes.LightGreen;
+            }
+            else
+            {
+                hotkey = Key.None;
+                modifiers = ModifierKeys.None;
+                Background = SystemColors.ControlBrush;
+            }
+
+            Text = HotkeyToLocalizedString(modifiers, hotkey);
+        }
+
+        /// <summary>
+        /// Set the registration interface the control is working on.
+        /// The registration interface is looked up by given hotkey combination string.
+        /// </summary>
+        /// <param name="hotkeyString">Hotkey combination string.</param>
+        internal void SetHotkeyRegistration(string hotkeyString) => SetHotkeyRegistration(FindRegistration(hotkeyString));
+
+        /// <summary>
+        /// Change the hotkey to given combination.
+        /// </summary>
+        /// <param name="hotkeyString">Hotkey combination string.</param>
+        internal void ChangeHotkey(string hotkeyString)
+        {
+            hotkey = KeyFromString(hotkeyString);
+            modifiers = ModifierKeysFromString(hotkeyString);
             Redraw(true);
         }
 
@@ -154,25 +154,29 @@ namespace SystemTrayMenu.UserInterface
         /// <param name="key">The virtual key code.</param>
         /// <param name="handler">A HotKeyHandler, this will be called to handle the hotkey press.</param>
         /// <returns>the hotkey number, -1 if failed.</returns>
-        public int RegisterHotKey(ModifierKeys modifiers, Key key, Action handler)
+        internal int RegisterHotKey(ModifierKeys modifiers, Key key, Action handler)
         {
             if (key == Key.None)
             {
+                Background = SystemColors.ControlBrush;
                 return 0;
             }
 
             try
             {
-                hotkeyHandle = GlobalHotkeys.Register(modifiers, key);
+                hotkeyHandle = Register(modifiers, key);
             }
             catch (InvalidOperationException ex)
             {
+                Background = Brushes.IndianRed;
                 Log.Info($"Couldn't register hotkey modifier {modifiers} key {key} ex: " + ex.ToString());
                 return -1;
             }
 
             this.handler = handler;
             hotkeyHandle.KeyPressed += (_) => handler.Invoke();
+
+            Background = Brushes.LightGreen;
             return 1;
         }
 
@@ -186,7 +190,7 @@ namespace SystemTrayMenu.UserInterface
 
         private void UnregisterHotKey()
         {
-            GlobalHotkeys.Unregister(hotkeyHandle);
+            Unregister(hotkeyHandle);
             hotkeyHandle = null;
         }
 
@@ -283,7 +287,7 @@ namespace SystemTrayMenu.UserInterface
                 hotkey = Key.None;
             }
 
-            Text = GlobalHotkeys.HotkeyToLocalizedString(modifiers, hotkey);
+            Text = HotkeyToLocalizedString(modifiers, hotkey);
         }
 
         /// <summary>

UserInterface/SettingsWindow.xaml

@@ -50,7 +50,7 @@
                         </GroupBox>
                         <GroupBox Header="{u:Translate 'Hotkey'}">
                             <DockPanel LastChildFill="False">
-                                <local:HotkeySelector x:Name="textBoxHotkey" Text="None" AcceptsTab="False" MinWidth="200" VerticalAlignment="Center"/>
+                                <local:HotkeySelector x:Name="textBoxHotkey" AcceptsTab="False" MinWidth="200" VerticalAlignment="Center"/>
                                 <Button x:Name="buttonHotkeyDefault" DockPanel.Dock="Right" Content="{u:Translate 'Default'}" Margin="3" MinWidth="76" Click="ButtonHotkeyDefault_Click" VerticalAlignment="Center"/>
                             </DockPanel>
                         </GroupBox>

UserInterface/SettingsWindow.xaml.cs

@@ -86,7 +86,7 @@ namespace SystemTrayMenu.UserInterface
 
             checkBoxCheckForUpdates.IsChecked = Settings.Default.CheckForUpdates;
 
-            textBoxHotkey.SetHotkey(Settings.Default.HotKey);
+            textBoxHotkey.SetHotkeyRegistration(Settings.Default.HotKey);
 
             InitializeLanguage();
             void InitializeLanguage()
@@ -737,7 +737,7 @@ namespace SystemTrayMenu.UserInterface
 
         private void ButtonHotkeyDefault_Click(object sender, RoutedEventArgs e)
         {
-            textBoxHotkey.SetHotkey((string)Settings.Default.Properties["HotKey"].DefaultValue); // see Settings.Default.HotKey
+            textBoxHotkey.ChangeHotkey((string)Settings.Default.Properties["HotKey"].DefaultValue); // see Settings.Default.HotKey
         }
 
         private void ButtonGeneralDefault_Click(object sender, RoutedEventArgs e)