Add NHotkey library.

Wox/HotkeyControl.xaml.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Windows;
+using System.Windows.Data;
+using System.Windows.Documents;
+using System.Windows.Forms;
+using System.Windows.Input;
+using System.Windows.Media;
+using System.Windows.Media.Imaging;
+using System.Windows.Navigation;
+using System.Windows.Shapes;
+using Wox.Helper;
+using Wox.Plugin;
+using KeyEventArgs = System.Windows.Input.KeyEventArgs;
+using UserControl = System.Windows.Controls.UserControl;
+
+namespace Wox
+{
+    public partial class HotkeyControl : UserControl
+    {
+        public HotkeyControl()
+        {
+            InitializeComponent();
+        }
+
+        private void TbHotkey_OnPreviewKeyDown(object sender, KeyEventArgs e)
+        {
+            //when alt is pressed, the real key should be e.SystemKey
+            Key key = (e.Key == Key.System ? e.SystemKey : e.Key);
+
+            string text = string.Empty;
+            SpecialKeyState specialKeyState = new GloablHotkey().CheckModifiers();
+            if (specialKeyState.AltPressed)
+            {
+                text += "Alt ";
+            }
+            if (specialKeyState.CtrlPressed)
+            {
+                text += "Ctrl ";
+            }
+            if (specialKeyState.ShiftPressed)
+            {
+                text += "Shift ";
+            }
+            if (specialKeyState.WinPressed)
+            {
+                text += "Win ";
+            }
+            if(IsKeyAChar(key))
+            {
+                text += e.Key.ToString();
+            }
+            if (key == Key.Space)
+            {
+                text += "Space";
+            }
+
+            tbHotkey.Text = text;
+        }
+
+        private static bool IsKeyAChar(Key key)
+        {
+            return key >= Key.A && key <= Key.Z;
+        }
+    }
+}