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// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.
//
//
//
// Description: UIAutomation/Visual bridge
//
//
using System.Windows;
using System.Windows.Automation;
using System.Windows.Automation.Provider;
using System.Windows.Automation.Peers;
using System.Windows.Input;
using System.Windows.Threading;
namespace MS.Internal.Automation
{
// Automation Proxy for WCP elements - exposes WCP tree
// and properties to Automation.
//
// Currently builds tree based on Visual tree; many later incorporate
// parts of logical tree.
//
// Currently exposes just BoundingRectangle, ClassName, IsEnabled
// and IsKeyboardFocused properties.
internal class ElementProxy: IRawElementProviderFragmentRoot, IRawElementProviderAdviseEvents
{
//------------------------------------------------------
//
// Constructors
//
//------------------------------------------------------
#region Constructors
// private ctor - the Wrap() pseudo-ctor is used instead.
private ElementProxy(AutomationPeer peer)
{
if ((AutomationInteropReferenceType == ReferenceType.Weak) &&
(peer is UIElementAutomationPeer || peer is ContentElementAutomationPeer || peer is UIElement3DAutomationPeer))
{
_peer = new WeakReference(peer);
}
else
{
_peer = peer;
}
}
#endregion Constructors
//------------------------------------------------------
//
// Interface IRawElementProviderFragmentRoot
//
//------------ ------------------------------------------
#region Interface IRawElementProviderFragmentRoot
// Implementation of the interface that exposes this
// to UIAutomation.
//
// Interface IRawElementProviderFragmentRoot 'derives' from
// IRawElementProviderSimple and IRawElementProviderFragment,
// methods from those appear first below.
//
// Most of the interface methods on this interface need
// to get onto the Visual's context before they can access it,
// so use Dispatcher.Invoke to call a private method (in the
// private methods section of this class) that does the real work.
// IRawElementProviderSimple methods...
public object GetPatternProvider ( int pattern )
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return ElementUtil.Invoke(peer, new DispatcherOperationCallback( InContextGetPatternProvider ), pattern);
}
public object GetPropertyValue(int property)
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return ElementUtil.Invoke(peer, new DispatcherOperationCallback(InContextGetPropertyValue), property);
}
public ProviderOptions ProviderOptions
{
get
{
AutomationPeer peer = Peer;
if (peer == null)
{
return ProviderOptions.ServerSideProvider;
}
return (ProviderOptions)ElementUtil.Invoke(peer, state => ((ElementProxy)state).InContextGetProviderOptions(), this);
}
}
public IRawElementProviderSimple HostRawElementProvider
{
get
{
IRawElementProviderSimple host = null;
HostedWindowWrapper hwndWrapper = null;
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
hwndWrapper = (HostedWindowWrapper)ElementUtil.Invoke(
peer,
new DispatcherOperationCallback(InContextGetHostRawElementProvider),
null);
if(hwndWrapper != null)
host = GetHostHelper(hwndWrapper);
return host;
}
}
private IRawElementProviderSimple GetHostHelper(HostedWindowWrapper hwndWrapper)
{
return AutomationInteropProvider.HostProviderFromHandle(hwndWrapper.Handle);
}
// IRawElementProviderFragment methods...
public IRawElementProviderFragment Navigate( NavigateDirection direction )
{
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
return (IRawElementProviderFragment)ElementUtil.Invoke(peer, new DispatcherOperationCallback(InContextNavigate), direction);
}
public int [ ] GetRuntimeId()
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return (int []) ElementUtil.Invoke( peer, state => ((ElementProxy)state).InContextGetRuntimeId(), this);
}
public Rect BoundingRectangle
{
get
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return (Rect)ElementUtil.Invoke(peer, state => ((ElementProxy)state).InContextBoundingRectangle(), this);
}
}
public IRawElementProviderSimple [] GetEmbeddedFragmentRoots()
{
return null;
}
public void SetFocus()
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
ElementUtil.Invoke(peer, state => ((ElementProxy)state).InContextSetFocus(), this);
}
public IRawElementProviderFragmentRoot FragmentRoot
{
get
{
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
return (IRawElementProviderFragmentRoot) ElementUtil.Invoke( peer, state => ((ElementProxy)state).InContextFragmentRoot(), this);
}
}
// IRawElementProviderFragmentRoot methods..
public IRawElementProviderFragment ElementProviderFromPoint( double x, double y )
{
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
return (IRawElementProviderFragment) ElementUtil.Invoke( peer, new DispatcherOperationCallback( InContextElementProviderFromPoint ), new Point( x, y ) );
}
public IRawElementProviderFragment GetFocus()
{
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
return (IRawElementProviderFragment) ElementUtil.Invoke( peer, state => ((ElementProxy)state).InContextGetFocus(), this);
}
// Event support: EventMap is a static class and access is synchronized, so no need to access it in UI thread context.
// Directly add or remove the requested EventId from the EventMap from here.
// Note: We update the EventMap even if peer is not available that's because we still have to keep track of number of
// subscribers for the given event.
public void AdviseEventAdded(int eventID, int[] properties)
{
EventMap.AddEvent(eventID);
}
public void AdviseEventRemoved(int eventID, int[] properties)
{
EventMap.RemoveEvent(eventID);
}
#endregion Interface IRawElementProviderFragmentRoot
//------------------------------------------------------
//
// Internal Methods
//
//------------------------------------------------------
#region Internal Methods
// Wrap the found peer before shipping it over process boundary - static version for use outside ElementProxy.
internal static ElementProxy StaticWrap(AutomationPeer peer, AutomationPeer referencePeer)
{
ElementProxy result = null;
if (peer != null)
{
//referencePeer is well-connected, since UIA is asking us using it.
//However we are trying to return the peer that is possibly just created on some
//element in the middle of un-walked tree and we need to make sure it is fully
//"connected" or initialized before we return it to UIA.
//This method ensures it has the right _parent and other hookup.
peer = peer.ValidateConnected(referencePeer);
if (peer != null)
{
// Use the already created Wrapper proxy for peer if it is still alive
if(peer.ElementProxyWeakReference != null)
{
result = peer.ElementProxyWeakReference.Target as ElementProxy;
}
if(result == null)
{
result = new ElementProxy(peer);
peer.ElementProxyWeakReference = new WeakReference(result);
}
// If the peer corresponds to DataItem notify peer to add to storage to
// keep reference of peers going to the UIA Client
if(result != null)
{
if(peer.IsDataItemAutomationPeer())
{
peer.AddToParentProxyWeakRefCache();
}
}
}
}
return result;
}
// Needed to enable access from AutomationPeer.PeerFromProvider
internal AutomationPeer Peer
{
get
{
if (_peer is WeakReference)
{
AutomationPeer peer = (AutomationPeer)((WeakReference)_peer).Target;
return peer;
}
else
{
return (AutomationPeer)_peer;
}
}
}
#endregion Internal Methods
//------------------------------------------------------
//
// Private Methods
//
//------------------------------------------------------
#region Private Methods
// The signature of most of the folling methods is "object func( object arg )",
// since that's what the Conmtext.Invoke delegate requires.
// Return the element at specified coords.
private object InContextElementProviderFromPoint( object arg )
{
Point point = (Point)arg;
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
AutomationPeer peerFromPoint = peer.GetPeerFromPoint(point);
return StaticWrap(peerFromPoint, peer);
}
// Return proxy representing currently focused element (if any)
private object InContextGetFocus()
{
// Note: - what if a custom element - eg anchor in a text box - has focus?
// won't have a UIElement there, can we even find the host?
// If it implements Automation, can hand over to it, but if it doesn't,
// would like nearest item, drill in using visual tree?
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
AutomationPeer focusedPeer = AutomationPeer.AutomationPeerFromInputElement(Keyboard.FocusedElement);
return StaticWrap(focusedPeer, peer);
}
// redirect to AutomationPeer
private object InContextGetPatternProvider(object arg)
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return peer.GetWrappedPattern((int)arg);
}
// Return proxy representing element in specified direction (parent/next/firstchild/etc.)
private object InContextNavigate( object arg )
{
NavigateDirection direction = (NavigateDirection) arg;
AutomationPeer dest;
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
switch( direction )
{
case NavigateDirection.Parent:
dest = peer.GetParent();
break;
case NavigateDirection.FirstChild:
if (!peer.IsInteropPeer)
{
dest = peer.GetFirstChild();
}
else
{
return peer.GetInteropChild();
}
break;
case NavigateDirection.LastChild:
if (!peer.IsInteropPeer)
{
dest = peer.GetLastChild();
}
else
{
return peer.GetInteropChild();
}
break;
case NavigateDirection.NextSibling:
dest = peer.GetNextSibling();
break;
case NavigateDirection.PreviousSibling:
dest = peer.GetPreviousSibling();
break;
default:
dest = null;
break;
}
return StaticWrap(dest, peer);
}
// Return value for specified property; or null if not supported
private object InContextGetProviderOptions()
{
ProviderOptions options = ProviderOptions.ServerSideProvider;
AutomationPeer peer = Peer;
if (peer == null)
{
return options;
}
if (peer.IsHwndHost)
options |= ProviderOptions.OverrideProvider;
return options;
}
// Return value for specified property; or null if not supported
private object InContextGetPropertyValue ( object arg )
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return peer.GetPropertyValue((int)arg);
}
/// Returns whether this is the Root of the WCP tree or not
private object InContextGetHostRawElementProvider( object unused )
{
AutomationPeer peer = Peer;
if (peer == null)
{
return null;
}
return peer.GetHostRawElementProvider();
}
// Return unique ID for this element...
private object InContextGetRuntimeId()
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return peer.GetRuntimeId();
}
// Return bounding rectangle (screen coords) for this element...
private object InContextBoundingRectangle()
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
return peer.GetBoundingRectangle();
}
// Set focus to this element...
private object InContextSetFocus()
{
AutomationPeer peer = Peer;
if (peer == null)
{
throw new ElementNotAvailableException();
}
peer.SetFocus();
return null;
}
// Return proxy representing the root of this WCP tree...
private object InContextFragmentRoot()
{
AutomationPeer peer = Peer;
AutomationPeer root = peer;
if (root == null)
{
return null;
}
while(true)
{
AutomationPeer parent = root.GetParent();
if(parent == null) break;
root = parent;
}
return StaticWrap(root, peer);
}
#region disable switch for ElementProxy weak reference fix
internal enum ReferenceType
{
Strong,
Weak
}
// Returns RefrenceType.Strong if key AutomationWeakReferenceDisallow under
// "HKEY_LOCAL_MACHINE\Software\Microsoft\.NETFramework\Windows Presentation Foundation\Features"
// is set to 1 else returns ReferenceType.Weak. The registry key will be read only once.
internal static ReferenceType AutomationInteropReferenceType
{
get
{
if (_shouldCheckInTheRegistry)
{
if (RegistryKeys.ReadLocalMachineBool(RegistryKeys.WPF_Features, RegistryKeys.value_AutomationWeakReferenceDisallow))
{
_automationInteropReferenceType = ReferenceType.Strong;
}
_shouldCheckInTheRegistry = false;
}
return _automationInteropReferenceType;
}
}
private static ReferenceType _automationInteropReferenceType = ReferenceType.Weak;
private static bool _shouldCheckInTheRegistry = true;
#endregion
#endregion Private Methods
//------------------------------------------------------
//
// Private Fields
//
//------------------------------------------------------
#region Private Fields
private readonly object _peer;
#endregion Private Fields
}
}
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