KeyGesture.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / Input / Command / KeyGesture.cs / 1 / KeyGesture.cs
                        
                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: The KeyGesture class is used by the developer to create Keyboard Input Bindings 
//
//              See spec at : [....]/coreUI/Specs/Commanding%20--%20design.htm 
//
//* KeyGesture class serves the purpose of Input Bindings for Keyboard Device.
//* one will be passing the instance of this around with CommandLink to represent Accelerator Keys
// 
// History:
//  06/01/2003 : [....] - Created 
// 
//---------------------------------------------------------------------------
using System; 
using System.Globalization;
using System.Windows.Input;
using System.Windows;
using System.Windows.Markup; 
using System.ComponentModel;
using MS.Internal.PresentationCore; 
 
namespace System.Windows.Input
{ 
    /// 
    /// KeyGesture - Key and Modifier combination.
    ///              Can be set on properties of KeyBinding and RoutedCommand.
    ///  
    [TypeConverter(typeof(KeyGestureConverter))]
    [ValueSerializer(typeof(KeyGestureValueSerializer))] 
    public class KeyGesture : InputGesture 
    {
        //----------------------------------------------------- 
        //
        //  Constructors
        //
        //----------------------------------------------------- 
#region Constructors
        ///  
        ///  constructor 
        /// 
        /// key 
        public KeyGesture(Key key)
            : this(key, ModifierKeys.None)
        {
        } 

        ///  
        ///  constructor 
        /// 
        /// modifiers 
        /// key
        public KeyGesture(Key key, ModifierKeys modifiers)
            : this(key, modifiers, String.Empty, true)
        { 
        }
 
        ///  
        ///  constructor
        ///  
        /// modifiers
        /// key
        /// display string
        public KeyGesture(Key key, ModifierKeys modifiers, string displayString) 
            : this(key, modifiers, displayString, true)
        { 
        } 

 
        /// 
        /// Internal constructor used by KeyBinding to avoid key and modifier validation
        /// This allows setting KeyBinding.Key and KeyBinding.Modifiers without regard
        /// to order. 
        /// 
        /// Key 
        /// Modifiers 
        /// If true, throws an exception if the key and modifier are not valid
        internal KeyGesture(Key key, ModifierKeys modifiers, bool validateGesture) 
            : this(key, modifiers, String.Empty, validateGesture)
        {
        }
 
        /// 
        /// Private constructor that does the real work. 
        ///  
        /// Key
        /// Modifiers 
        /// display string
        /// If true, throws an exception if the key and modifier are not valid
        private KeyGesture(Key key, ModifierKeys modifiers, string displayString, bool validateGesture)
        { 
            if(!ModifierKeysConverter.IsDefinedModifierKeys(modifiers))
                throw new InvalidEnumArgumentException("modifiers", (int)modifiers, typeof(ModifierKeys)); 
 
            if(!IsDefinedKey(key))
                throw new InvalidEnumArgumentException("key", (int)key, typeof(Key)); 

            if (displayString == null)
                throw new ArgumentNullException("displayString");
 
            if(validateGesture && !IsValid(key, modifiers))
            { 
                throw new NotSupportedException(SR.Get(SRID.KeyGesture_Invalid, modifiers, key)); 
            }
 
            _modifiers = modifiers;
            _key = key;
            _displayString = displayString;
        } 
#endregion Constructors
 
        //------------------------------------------------------ 
        //
        //  Public Methods 
        //
        //-----------------------------------------------------
#region Public Methods
        ///  
        /// Modifier
        ///  
        public ModifierKeys Modifiers 
        {
            get 
            {
                return _modifiers;
            }
        } 

        ///  
        /// Key 
        /// 
        public Key Key 
        {
            get
            {
                return _key; 
            }
        } 
 
        /// 
        /// DisplayString 
        /// 
        public string DisplayString
        {
            get 
            {
                return _displayString; 
            } 
        }
 
        /// 
        /// Returns a string that can be used to display the KeyGesture.  If the
        /// DisplayString was set by the constructor, it is returned.  Otherwise
        /// a suitable string is created from the Key and Modifiers, with any 
        /// conversions being governed by the given CultureInfo.
        ///  
        /// the culture used when creating a string from Key and Modifiers 
        public string GetDisplayStringForCulture(CultureInfo culture)
        { 
            // return the DisplayString, if it was set by the ctor
            if (!String.IsNullOrEmpty(_displayString))
            {
                return _displayString; 
            }
 
            // otherwise use the type converter 
            return (string)_keyGestureConverter.ConvertTo(null, culture, this, typeof(string));
        } 

        /// 
        /// Compares InputEventArgs with current Input
        ///  
        /// the element to receive the command
        /// inputEventArgs to compare to 
        /// True - KeyGesture matches, false otherwise. 
        /// 
        public override bool Matches(object targetElement, InputEventArgs inputEventArgs) 
        {
            KeyEventArgs keyEventArgs = inputEventArgs as KeyEventArgs;
            if(keyEventArgs != null && IsDefinedKey(keyEventArgs.Key))
            { 
                return ( ( (int)Key == (int)keyEventArgs.RealKey ) && ( this.Modifiers == Keyboard.Modifiers ) );
            } 
            return false; 
        }
 
        // Check for Valid enum, as any int can be casted to the enum.
        internal static bool IsDefinedKey(Key key)
        {
            return (key >= Key.None && key <= Key.OemClear); 
        }
 
#endregion Public Methods 

        //------------------------------------------------------ 
        //
        //  Internal Methods
        //
        //------------------------------------------------------ 
#region Internal Methods
        /// 
        /// Is Valid Keyboard input to process for commands 
        ///
        internal static bool IsValid(Key key, ModifierKeys modifiers) 
        {
            //
            //  Don't enforce any rules on the Function keys or on the number pad keys.
            // 
            if(!( ( key >= Key.F1 && key <= Key.F24 ) || ( key >= Key.NumPad0 && key <= Key.Divide ) ))
            { 
                // 
                //  We check whether Control/Alt/Windows key is down for modifiers. We don't check
                //  for shift at this time as Shift with any combination is already covered in above check. 
                //  Shift alone as modifier case, we defer to the next condition to avoid conflicing with
                //  TextInput.

                if(( modifiers & ( ModifierKeys.Control | ModifierKeys.Alt | ModifierKeys.Windows ) ) != 0) 
                {
                    switch(key) 
                    { 
                        case Key.LeftCtrl:
                        case Key.RightCtrl: 
                        case Key.LeftAlt:
                        case Key.RightAlt:
                        case Key.LWin:
                        case Key.RWin: 
                            return false;
 
                        default: 
                            return true;
                    } 
                }
                else if(( key >= Key.D0 && key <= Key.D9 ) || ( key >= Key.A && key <= Key.Z ))
                {
                    return false; 
                }
            } 
            return true; 
        }
 
        /// 
        /// Decode the strings keyGestures and displayStrings, creating a sequence
        /// of KeyGestures.  Add each KeyGesture to the given InputGestureCollection.
        /// The two input strings typically come from a resource file. 
        /// 
        internal static void AddGesturesFromResourceStrings(string keyGestures, string displayStrings, InputGestureCollection gestures) 
        { 
            while (!String.IsNullOrEmpty(keyGestures))
            { 
                string keyGestureToken;
                string keyDisplayString;

                // break apart first gesture from the rest 
                int index = keyGestures.IndexOf(MULTIPLEGESTURE_DELIMITER, StringComparison.Ordinal);
                if (index >= 0) 
                {   // multiple gestures exist 
                    keyGestureToken  = keyGestures.Substring(0, index);
                    keyGestures   = keyGestures.Substring(index + 1); 
                }
                else
                {
                    keyGestureToken = keyGestures; 
                    keyGestures = String.Empty;
                } 
 
                // similarly, break apart first display string from the rest
                index = displayStrings.IndexOf(MULTIPLEGESTURE_DELIMITER, StringComparison.Ordinal); 
                if (index >= 0)
                {   // multiple display strings exist
                    keyDisplayString  = displayStrings.Substring(0, index);
                    displayStrings   = displayStrings.Substring(index + 1); 
                }
                else 
                { 
                    keyDisplayString = displayStrings;
                    displayStrings = String.Empty; 
                }

                KeyGesture keyGesture = CreateFromResourceStrings(keyGestureToken, keyDisplayString);
 
                if (keyGesture != null)
                { 
                    gestures.Add(keyGesture); 
                }
            } 
        }

        internal static KeyGesture CreateFromResourceStrings(string keyGestureToken, string keyDisplayString)
        { 
            // combine the gesture and the display string, producing a string
            // that the type converter will recognize 
            if (!String.IsNullOrEmpty(keyDisplayString)) 
            {
                keyGestureToken += KeyGestureConverter.DISPLAYSTRING_SEPARATOR + keyDisplayString; 
            }

            return _keyGestureConverter.ConvertFromInvariantString(keyGestureToken) as KeyGesture;
        } 

#endregion Internal Methods 
 
        //-----------------------------------------------------
        // 
        //   Private Fields
        //
        //------------------------------------------------------
#region Private Fields 
        private ModifierKeys   _modifiers = ModifierKeys.None;
        private Key            _key = Key.None; 
        private string         _displayString; 
        private const string MULTIPLEGESTURE_DELIMITER = ";";
        private static TypeConverter _keyGestureConverter = new KeyGestureConverter(); 
        //private static bool    _classRegistered = false;
#endregion Private Fields
    }
 } 


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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