HwndSourceKeyboardInputSite.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / InterOp / HwndSourceKeyboardInputSite.cs / 1407647 / HwndSourceKeyboardInputSite.cs
                        

                        
                            using System; 
using System.Windows.Input;
using System.Collections;
using MS.Win32;
using System.Windows.Media; 
using System.Windows.Threading;
 
using SR=MS.Internal.PresentationCore.SR; 
using SRID=MS.Internal.PresentationCore.SRID;
using System.Security ; 
using MS.Internal.PresentationCore;

namespace System.Windows.Interop
{ 
    internal class HwndSourceKeyboardInputSite : IKeyboardInputSite
    { 
        ///  
        /// Critical: satisfies a LinkDemand for 'UIPermissionAttribute' on method
        /// 'System.Windows.Interop.IKeyboardInputSink.set_KeyboardInputSite(System.Windows.Interop.IKeyboardInputSite)'. 
        /// 
        [SecurityCritical]
        public HwndSourceKeyboardInputSite(HwndSource source, IKeyboardInputSink sink)
        { 
            if(source == null)
            { 
                throw new ArgumentNullException("source"); 
            }
            if(sink == null) 
            {
                throw new ArgumentNullException("sink");
            }
            if(!(sink is UIElement)) 
            {
                throw new ArgumentException(SR.Get(SRID.KeyboardSinkMustBeAnElement), "sink"); 
            } 

            _source = source; 

            _sink = sink;
            _sink.KeyboardInputSite = this;
 
            _sinkElement = sink as UIElement;
        } 
 
#region IKeyboardInputSite
        ///  
        ///     Unregisters a child KeyboardInputSink from this sink.
        /// 
        /// 
        ///     Requires unmanaged code permission. 
        /// 
        /// 
        ///     Critical - calls CriticalUnregister. 
        ///     TreatAsSafe: - Interface declaration demands unrestricted UI permission
        /// 
        [ SecurityCritical,SecurityTreatAsSafe ]
        void IKeyboardInputSite.Unregister()
        {
            CriticalUnregister(); 
        }
 
        ///  
        ///     Unregisters a child KeyboardInputSink from this sink.
        ///  
        /// 
        ///     Critical - calls CriticalUnregisterKeyboardInputSink
        /// 
        [ SecurityCritical ] 
        internal void CriticalUnregister()
        { 
            if(_source != null && _sink != null) 
            {
                _source.CriticalUnregisterKeyboardInputSink(this); 
                _sink.KeyboardInputSite = null;
            }

            _source = null; 
            _sink = null;
        } 
        ///  
        ///     Returns the sink associated with this site (the "child", not
        ///     the "parent" sink that owns the site).  There's no way of 
        ///     getting from the site to the parent sink.
        /// 
        IKeyboardInputSink IKeyboardInputSite.Sink
        { 
            get
            { 
                return _sink; 
            }
        } 

        /// 
        ///     Components call this when they want to move focus ("tab") but
        ///     have nowhere further to tab within their own component.  Return 
        ///     value is true if the site moved focus, false if the calling
        ///     component still has focus and should wrap around. 
        ///  
        bool IKeyboardInputSite.OnNoMoreTabStops(TraversalRequest request)
        { 
            bool traversed = false;

            if(_sinkElement != null)
            { 
                traversed = _sinkElement.MoveFocus(request);
            } 
 
            return traversed;
        } 

#endregion IKeyboardInputSite

        private HwndSource _source; 
        private IKeyboardInputSink _sink;
        private UIElement _sinkElement; 
    } 
}

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

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