Code:
/ 4.0 / 4.0 / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / UIAutomation / UIAutomationClient / MS / Internal / Automation / InvokeHandlers.cs / 1305600 / InvokeHandlers.cs
//---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: class which defines the delegates used to invoke the client event handlers // // History: // 06/17/2003 : BrendanM Ported to WCP // //--------------------------------------------------------------------------- using System; using System.Windows.Automation; using System.ComponentModel; using System.Threading; using System.Diagnostics; namespace MS.Internal.Automation { // Temp class used to bundle focus event time along with the usual // focus change information. The InvokeHandler code below that dispatches // focus change events checks the time, and drops any events thta have // a timestamp that is earlier than the most recently dispatched event. // (This avoids race conditions from events from WinEvents and events from UIA, // which arrive on different threads, and which can drift during their processing, // since winevents get scope-checked - slow - as part of their processing before // being queued, whereas UIA events are just queued up. The key issue with any // timestamp checking is that it happens *after* the two streams of events have // been merged - otherwise they could just drift again. This is the case here, // since the InvokeHandler code is called by the callbackqueue, which services // both these types of events.) // // This code is "temp" - there's a work item to remove AsyncOperations, and // removing that should result in a cleaner solution to passing the eventTime // around, perhaps passing it directly to the InvokeHandlers method instead of // tunnelling it into a 'wrapped' AutomationFocusChangedEventArgs. internal class InternalAutomationFocusChangedEventArgs : AutomationFocusChangedEventArgs { internal AutomationFocusChangedEventArgs _args; internal uint _eventTime; internal InternalAutomationFocusChangedEventArgs(int idObject, int idChild, uint eventTime) : base(idObject, idChild) { _args = new AutomationFocusChangedEventArgs(idObject, idChild); _eventTime = eventTime; } }; // This class manages dispatching events to the different types of // UIA event delegates internal static class InvokeHandlers { //----------------------------------------------------- // // Internal Methods // //----------------------------------------------------- #region Internal Methods // The method that gets called from CallbackQueue's thread. Uses Post to invoke the callback on the proper thread. internal static void InvokeClientHandler(Delegate clientCallback, AutomationElement srcEl, AutomationEventArgs args) { try { if (args is AutomationPropertyChangedEventArgs) { ((AutomationPropertyChangedEventHandler)clientCallback)(srcEl, (AutomationPropertyChangedEventArgs)args); } else if (args is StructureChangedEventArgs) { ((StructureChangedEventHandler)clientCallback)(srcEl, (StructureChangedEventArgs)args); } else if (args is InternalAutomationFocusChangedEventArgs) { AutomationFocusChangedEventArgs realArgs = ((InternalAutomationFocusChangedEventArgs)args)._args; // For focus events, check that the event is actually more recent than the last one (see note at top of file). // Since the timestamps can wrap around, subtract and measure the delta instead of just comparing them. // Any events that appear to have taken place within the 5 seconds before the last event we got will be ignored. // (Because of wraparound, certain before- and after- time spans share the same deltas; 5000ms before has the // same value as MAXUINT-5000ms after. Since we're just trying to filter out very recent event race conditions, // confine this test to a small window, just the most recent 5 seconds. That means you'd have to wait a *very* // long time without any focus changes before getting a false positive here.) uint eventTime = ((InternalAutomationFocusChangedEventArgs)args)._eventTime; if (_lastFocusEventTime != 0) { uint delta = _lastFocusEventTime - eventTime; // Exclude events that happend before the last one, but do allow any that happened "at the same time", // (delta==0) since they likely actually happened after, but within the resolution of the event timer. if (delta < 5000 && delta != 0) { return; } } _lastFocusEventTime = eventTime; ((AutomationFocusChangedEventHandler)clientCallback)(srcEl, realArgs); } else { ((AutomationEventHandler)clientCallback)(srcEl, args); } } catch (Exception e) { if (Misc.IsCriticalException(e)) throw; // Since we can't predict what exceptions an outside client might throw intentionally ignore all } } #endregion Internal Methods //------------------------------------------------------ // // Internal Fields // //----------------------------------------------------- #region Internal Fields internal static uint _lastFocusEventTime; #endregion Internal Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved. //---------------------------------------------------------------------------- // //// Copyright (C) Microsoft Corporation. All rights reserved. // // // // Description: class which defines the delegates used to invoke the client event handlers // // History: // 06/17/2003 : BrendanM Ported to WCP // //--------------------------------------------------------------------------- using System; using System.Windows.Automation; using System.ComponentModel; using System.Threading; using System.Diagnostics; namespace MS.Internal.Automation { // Temp class used to bundle focus event time along with the usual // focus change information. The InvokeHandler code below that dispatches // focus change events checks the time, and drops any events thta have // a timestamp that is earlier than the most recently dispatched event. // (This avoids race conditions from events from WinEvents and events from UIA, // which arrive on different threads, and which can drift during their processing, // since winevents get scope-checked - slow - as part of their processing before // being queued, whereas UIA events are just queued up. The key issue with any // timestamp checking is that it happens *after* the two streams of events have // been merged - otherwise they could just drift again. This is the case here, // since the InvokeHandler code is called by the callbackqueue, which services // both these types of events.) // // This code is "temp" - there's a work item to remove AsyncOperations, and // removing that should result in a cleaner solution to passing the eventTime // around, perhaps passing it directly to the InvokeHandlers method instead of // tunnelling it into a 'wrapped' AutomationFocusChangedEventArgs. internal class InternalAutomationFocusChangedEventArgs : AutomationFocusChangedEventArgs { internal AutomationFocusChangedEventArgs _args; internal uint _eventTime; internal InternalAutomationFocusChangedEventArgs(int idObject, int idChild, uint eventTime) : base(idObject, idChild) { _args = new AutomationFocusChangedEventArgs(idObject, idChild); _eventTime = eventTime; } }; // This class manages dispatching events to the different types of // UIA event delegates internal static class InvokeHandlers { //----------------------------------------------------- // // Internal Methods // //----------------------------------------------------- #region Internal Methods // The method that gets called from CallbackQueue's thread. Uses Post to invoke the callback on the proper thread. internal static void InvokeClientHandler(Delegate clientCallback, AutomationElement srcEl, AutomationEventArgs args) { try { if (args is AutomationPropertyChangedEventArgs) { ((AutomationPropertyChangedEventHandler)clientCallback)(srcEl, (AutomationPropertyChangedEventArgs)args); } else if (args is StructureChangedEventArgs) { ((StructureChangedEventHandler)clientCallback)(srcEl, (StructureChangedEventArgs)args); } else if (args is InternalAutomationFocusChangedEventArgs) { AutomationFocusChangedEventArgs realArgs = ((InternalAutomationFocusChangedEventArgs)args)._args; // For focus events, check that the event is actually more recent than the last one (see note at top of file). // Since the timestamps can wrap around, subtract and measure the delta instead of just comparing them. // Any events that appear to have taken place within the 5 seconds before the last event we got will be ignored. // (Because of wraparound, certain before- and after- time spans share the same deltas; 5000ms before has the // same value as MAXUINT-5000ms after. Since we're just trying to filter out very recent event race conditions, // confine this test to a small window, just the most recent 5 seconds. That means you'd have to wait a *very* // long time without any focus changes before getting a false positive here.) uint eventTime = ((InternalAutomationFocusChangedEventArgs)args)._eventTime; if (_lastFocusEventTime != 0) { uint delta = _lastFocusEventTime - eventTime; // Exclude events that happend before the last one, but do allow any that happened "at the same time", // (delta==0) since they likely actually happened after, but within the resolution of the event timer. if (delta < 5000 && delta != 0) { return; } } _lastFocusEventTime = eventTime; ((AutomationFocusChangedEventHandler)clientCallback)(srcEl, realArgs); } else { ((AutomationEventHandler)clientCallback)(srcEl, args); } } catch (Exception e) { if (Misc.IsCriticalException(e)) throw; // Since we can't predict what exceptions an outside client might throw intentionally ignore all } } #endregion Internal Methods //------------------------------------------------------ // // Internal Fields // //----------------------------------------------------- #region Internal Fields internal static uint _lastFocusEventTime; #endregion Internal Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. All rights reserved.
Link Menu

This book is available now!
Buy at Amazon US or
Buy at Amazon UK
- DataGridViewEditingControlShowingEventArgs.cs
- DocumentPageView.cs
- Matrix3D.cs
- KeyToListMap.cs
- KeyGesture.cs
- ToolStripContainerDesigner.cs
- ConnectivityStatus.cs
- XmlQueryStaticData.cs
- HierarchicalDataBoundControl.cs
- DefaultExpression.cs
- XPathSingletonIterator.cs
- WebResourceUtil.cs
- FragmentQueryProcessor.cs
- SerializationException.cs
- MimeWriter.cs
- StreamReader.cs
- NotifyInputEventArgs.cs
- SelectionGlyphBase.cs
- CalendarDayButton.cs
- ScalarConstant.cs
- SingleAnimationBase.cs
- ParentQuery.cs
- DataGridViewRowConverter.cs
- latinshape.cs
- UnknownWrapper.cs
- EntityStoreSchemaGenerator.cs
- SettingsBindableAttribute.cs
- CleanUpVirtualizedItemEventArgs.cs
- HtmlShim.cs
- MemberDomainMap.cs
- BinarySerializer.cs
- RectIndependentAnimationStorage.cs
- RangeValueProviderWrapper.cs
- WindowsListViewItemCheckBox.cs
- SyndicationElementExtension.cs
- RecognizerBase.cs
- ItemType.cs
- RegistryKey.cs
- XmlMemberMapping.cs
- BaseValidatorDesigner.cs
- ActiveDocumentEvent.cs
- CodePropertyReferenceExpression.cs
- ConsoleTraceListener.cs
- invalidudtexception.cs
- PriorityQueue.cs
- SiteMapPath.cs
- DeclaredTypeElementCollection.cs
- LinkConverter.cs
- AnimationException.cs
- RepeaterItem.cs
- TextSchema.cs
- OpCodes.cs
- ShapeTypeface.cs
- Buffer.cs
- AccessorTable.cs
- PaintValueEventArgs.cs
- hebrewshape.cs
- Evaluator.cs
- HierarchicalDataBoundControl.cs
- Style.cs
- ArcSegment.cs
- X509CertificateChain.cs
- ServiceMemoryGates.cs
- ComboBoxRenderer.cs
- ToolStripTextBox.cs
- SQLInt32.cs
- ToolbarAUtomationPeer.cs
- AddIn.cs
- ExtensibleClassFactory.cs
- ClientEndpointLoader.cs
- CodeValidator.cs
- VideoDrawing.cs
- XmlSchemaChoice.cs
- MouseActionValueSerializer.cs
- ArgIterator.cs
- DataServiceException.cs
- SspiSecurityTokenParameters.cs
- ChannelRequirements.cs
- SafeProcessHandle.cs
- GCHandleCookieTable.cs
- KeyBinding.cs
- DataServiceProviderWrapper.cs
- MailDefinition.cs
- DelegateHelpers.cs
- HelpInfo.cs
- Lasso.cs
- GetLedgerRequest.cs
- SQLDouble.cs
- SecurityElementBase.cs
- RadioButtonPopupAdapter.cs
- Events.cs
- GenericParameterDataContract.cs
- TypeDelegator.cs
- ServicesUtilities.cs
- ApplicationException.cs
- SecurityDocument.cs
- RemotingAttributes.cs
- Keywords.cs
- XslVisitor.cs
- Rule.cs