EventMap.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 / MS / Internal / Automation / EventMap.cs / 1606164 / EventMap.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// 
// Description: 
// Accessibility event map classes are used to determine if, and how many
// listeners there are for events and property changes. 
//
// History:
//  07/23/2003 : BrendanM Ported to WCP
// 
//---------------------------------------------------------------------------
 
using System; 
using System.Collections;
using System.Windows; 
using System.Windows.Automation;
using System.Windows.Automation.Peers;

using SR=MS.Internal.PresentationCore.SR; 
using SRID=MS.Internal.PresentationCore.SRID;
 
namespace MS.Internal.Automation 
{
    // Manages the event map that is used to determine if there are Automation 
    // clients interested in specific events.
    internal static class EventMap
    {
 
        private class EventInfo
        { 
            internal EventInfo() 
            {
                NumberOfListeners = 1; 
            }

            internal int NumberOfListeners;
        } 

        // Never inline, as we don't want to unnecessarily link the automation DLL. 
        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)] 
        private static bool IsKnownEvent(int id)
        { 
            if (    id == AutomationElementIdentifiers.ToolTipOpenedEvent.Id
                ||  id == AutomationElementIdentifiers.ToolTipClosedEvent.Id
                ||  id == AutomationElementIdentifiers.MenuOpenedEvent.Id
                ||  id == AutomationElementIdentifiers.MenuClosedEvent.Id 
                ||  id == AutomationElementIdentifiers.AutomationFocusChangedEvent.Id
                ||  id == InvokePatternIdentifiers.InvokedEvent.Id 
                ||  id == SelectionItemPatternIdentifiers.ElementAddedToSelectionEvent.Id 
                ||  id == SelectionItemPatternIdentifiers.ElementRemovedFromSelectionEvent.Id
                ||  id == SelectionItemPatternIdentifiers.ElementSelectedEvent.Id 
                ||  id == SelectionPatternIdentifiers.InvalidatedEvent.Id
                ||  id == TextPatternIdentifiers.TextSelectionChangedEvent.Id
                ||  id == TextPatternIdentifiers.TextChangedEvent.Id
                ||  id == AutomationElementIdentifiers.AsyncContentLoadedEvent.Id 
                ||  id == AutomationElementIdentifiers.AutomationPropertyChangedEvent.Id
                ||  id == AutomationElementIdentifiers.StructureChangedEvent.Id 
                ||  ((SynchronizedInputPatternIdentifiers.InputReachedTargetEvent != null) && (id == SynchronizedInputPatternIdentifiers.InputReachedTargetEvent.Id)) 
                ||  ((SynchronizedInputPatternIdentifiers.InputReachedOtherElementEvent != null) && (id == SynchronizedInputPatternIdentifiers.InputReachedOtherElementEvent.Id))
                ||  ((SynchronizedInputPatternIdentifiers.InputDiscardedEvent != null) && (id == SynchronizedInputPatternIdentifiers.InputDiscardedEvent.Id))) 
            {
                return true;
            }
 
            return false;
        } 
 
        // Never inline, as we don't want to unnecessarily link the automation DLL.
        [System.Runtime.CompilerServices.MethodImpl(System.Runtime.CompilerServices.MethodImplOptions.NoInlining)] 
        private static AutomationEvent GetRegisteredEventObjectHelper(AutomationEvents eventId)
        {
            AutomationEvent eventObject = null;
 
            switch(eventId)
            { 
                case AutomationEvents.ToolTipOpened:                                        eventObject = AutomationElementIdentifiers.ToolTipOpenedEvent; break; 
                case AutomationEvents.ToolTipClosed:                                        eventObject = AutomationElementIdentifiers.ToolTipClosedEvent; break;
                case AutomationEvents.MenuOpened:                                           eventObject = AutomationElementIdentifiers.MenuOpenedEvent; break; 
                case AutomationEvents.MenuClosed:                                           eventObject = AutomationElementIdentifiers.MenuClosedEvent; break;
                case AutomationEvents.AutomationFocusChanged:                               eventObject = AutomationElementIdentifiers.AutomationFocusChangedEvent; break;
                case AutomationEvents.InvokePatternOnInvoked:                               eventObject = InvokePatternIdentifiers.InvokedEvent; break;
                case AutomationEvents.SelectionItemPatternOnElementAddedToSelection:        eventObject = SelectionItemPatternIdentifiers.ElementAddedToSelectionEvent; break; 
                case AutomationEvents.SelectionItemPatternOnElementRemovedFromSelection:    eventObject = SelectionItemPatternIdentifiers.ElementRemovedFromSelectionEvent; break;
                case AutomationEvents.SelectionItemPatternOnElementSelected:                eventObject = SelectionItemPatternIdentifiers.ElementSelectedEvent; break; 
                case AutomationEvents.SelectionPatternOnInvalidated:                        eventObject = SelectionPatternIdentifiers.InvalidatedEvent; break; 
                case AutomationEvents.TextPatternOnTextSelectionChanged:                    eventObject = TextPatternIdentifiers.TextSelectionChangedEvent; break;
                case AutomationEvents.TextPatternOnTextChanged:                             eventObject = TextPatternIdentifiers.TextChangedEvent; break; 
                case AutomationEvents.AsyncContentLoaded:                                   eventObject = AutomationElementIdentifiers.AsyncContentLoadedEvent; break;
                case AutomationEvents.PropertyChanged:                                      eventObject = AutomationElementIdentifiers.AutomationPropertyChangedEvent; break;
                case AutomationEvents.StructureChanged:                                     eventObject = AutomationElementIdentifiers.StructureChangedEvent; break;
                case AutomationEvents.InputReachedTarget:                                   eventObject = SynchronizedInputPatternIdentifiers.InputReachedTargetEvent; break; 
                case AutomationEvents.InputReachedOtherElement:                             eventObject = SynchronizedInputPatternIdentifiers.InputReachedOtherElementEvent; break;
                case AutomationEvents.InputDiscarded:                                       eventObject = SynchronizedInputPatternIdentifiers.InputDiscardedEvent; break; 
 
                default:
                    throw new ArgumentException(SR.Get(SRID.Automation_InvalidEventId), "eventId"); 
            }

            if ((eventObject != null) && (!_eventsTable.ContainsKey(eventObject.Id)))
            { 
                eventObject = null;
            } 
 
            return (eventObject);
        } 

        internal static void AddEvent(int idEvent)
        {
            lock (_lock) 
            {
                if (_eventsTable == null) 
                    _eventsTable = new Hashtable(20, .1f); 

                if (_eventsTable.ContainsKey(idEvent)) 
                {
                    EventInfo info = (EventInfo)_eventsTable[idEvent];
                    info.NumberOfListeners++;
                } 
                //  to avoid unbound memory allocations,
                //  register only events that we recognize 
                else if (IsKnownEvent(idEvent)) 
                {
                    _eventsTable[idEvent] = new EventInfo(); 
                }
            }
        }
 
        internal static void RemoveEvent(int idEvent)
        { 
            lock (_lock) 
            {
                if (_eventsTable != null) 
                {
                    // Decrement the count of listeners for this event
                    if (_eventsTable.ContainsKey(idEvent))
                    { 
                        EventInfo info = (EventInfo)_eventsTable[idEvent];
 
                        // Update or remove the entry based on remaining listeners 
                        info.NumberOfListeners--;
                        if (info.NumberOfListeners <= 0) 
                        {
                            _eventsTable.Remove(idEvent);

                            // If no more entries exist kill the table 
                            if (_eventsTable.Count == 0)
                            { 
                                _eventsTable = null; 
                            }
                        } 
                    }
                }
            }
        } 

        //  Unlike GetRegisteredEvent below, 
        //  HasRegisteredEvent does NOT cause automation DLLs loading 
        internal static bool HasRegisteredEvent(AutomationEvents eventId)
        { 
            lock (_lock)
            {
                if (_eventsTable != null && _eventsTable.Count != 0)
                { 
                    return (GetRegisteredEventObjectHelper(eventId) != null);
                } 
            } 
            return (false);
        } 

        internal static AutomationEvent GetRegisteredEvent(AutomationEvents eventId)
        {
            lock (_lock) 
            {
                if (_eventsTable != null && _eventsTable.Count != 0) 
                { 
                    return (GetRegisteredEventObjectHelper(eventId));
                } 
            }

            return (null);
        } 

        private static Hashtable _eventsTable;        // key=event id, data=listener count 
        private readonly static object _lock = new object(); 
    }
} 

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

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