UIElementAutomationPeer.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / Automation / Peers / UIElementAutomationPeer.cs / 3 / UIElementAutomationPeer.cs
                        
                        
                            using System; 
using System.Security;
using System.Windows;
using System.Windows.Input;
using System.Windows.Interop; 
using System.Windows.Media;
using System.Collections.Generic; 
 
using MS.Internal;
using SR=MS.Internal.PresentationCore.SR; 
using SRID=MS.Internal.PresentationCore.SRID;

namespace System.Windows.Automation.Peers
{ 

    /// 
    public class UIElementAutomationPeer: AutomationPeer 
    {
        /// 
        public UIElementAutomationPeer(UIElement owner)
        {
            if(owner == null)
            { 
                throw new ArgumentNullException("owner");
            } 
            _owner = owner; 
        }
 
        ///
        public UIElement Owner
        {
            get 
            {
                return _owner; 
            } 
        }
 
        ///
        /// This static helper creates an AutomationPeer for the specified element and
        /// caches it - that means the created peer is going to live long and shadow the
        /// element for its lifetime. The peer will be used by Automation to proxy the element, and 
        /// to fire events to the Automation when something happens with the element.
        /// The created peer is returned from this method and also from subsequent calls to this method 
        /// and . The type of the peer is determined by the 
        ///  virtual callback. If UIElement does not
        /// implement the callback, there will be no peer and this method will return 'null' (in other 
        /// words, there is no such thing as a 'default peer').
        ///
        public static AutomationPeer CreatePeerForElement(UIElement element)
        { 
            if(element == null)
            { 
                throw new ArgumentNullException("element"); 
            }
 
            return element.CreateAutomationPeer();
        }

        /// 
        public static AutomationPeer FromElement(UIElement element)
        { 
            if(element == null) 
            {
                throw new ArgumentNullException("element"); 
            }

            return element.GetAutomationPeer();
        } 

        /// 
        override protected List GetChildrenCore() 
        {
            List children = null; 

            iterate(_owner,
                    (IteratorCallback)delegate(AutomationPeer peer)
                    { 
                        if (children == null)
                            children = new List(); 
 
                        children.Add(peer);
                        return (false); 
                    });

            return children;
        } 

        /// 
        ///  
        ///     Critical - Calls critical AutomationPeer.Hwnd setter.
        ///  
        [SecurityCritical]
        internal static AutomationPeer GetRootAutomationPeer(Visual rootVisual, IntPtr hwnd)
        {
            AutomationPeer root = null; 

            iterate(rootVisual, 
                    (IteratorCallback)delegate(AutomationPeer peer) 
                    {
                        root = peer; 
                        return (true);
                    });

            if (root != null) 
            {
                root.Hwnd = hwnd; 
            } 

            return root; 
        }

        private delegate bool IteratorCallback(AutomationPeer peer);
 
        //
        private static bool iterate(DependencyObject parent, IteratorCallback callback) 
        { 
            bool done = false;
 
            if(parent != null)
            {
                AutomationPeer peer = null;
                int count = VisualTreeHelper.GetChildrenCount(parent); 
                for (int i = 0; i < count && !done; i++)
                { 
                    DependencyObject child = VisualTreeHelper.GetChild(parent, i); 

                    if(     child != null 
                        &&  child is UIElement
                        &&  (peer = CreatePeerForElement((UIElement)child)) != null  )
                    {
                        done = callback(peer); 
                    }
                    else if ( child != null 
                        &&    child is UIElement3D 
                        &&    (peer = UIElement3DAutomationPeer.CreatePeerForElement(((UIElement3D)child))) != null )
                    { 
                        done = callback(peer);
                    }
                    else
                    { 
                        done = iterate(child, callback);
                    } 
                } 
            }
 
            return done;
        }

        /// 
        override public object GetPattern(PatternInterface patternInterface)
        { 
            return null; 
        }
 

        //
        // P R O P E R T I E S
        // 

        /// 
        protected override AutomationControlType GetAutomationControlTypeCore() 
        {
            return AutomationControlType.Custom; 
        }

        ///
        protected override string GetAutomationIdCore() 
        {
            return (AutomationProperties.GetAutomationId(_owner)); 
        } 

        /// 
        protected override string GetNameCore()
        {
            return (AutomationProperties.GetName(_owner));
        } 

        /// 
        protected override string GetHelpTextCore() 
        {
            return (AutomationProperties.GetHelpText(_owner)); 
        }

        ///
        ///  
        ///     Critical    - Calls PresentationSource.CriticalFromVisual to get the source for this visual
        ///     TreatAsSafe - The returned PresenationSource object is not exposed and is only used for converting 
        ///                   co-ordinates to screen space. 
        /// 
        [SecurityCritical, SecurityTreatAsSafe] 
        override protected Rect GetBoundingRectangleCore()
        {
            PresentationSource presentationSource = PresentationSource.CriticalFromVisual(_owner);
 
            // If there's no source, the element is not visible, return empty rect
            if(presentationSource == null) 
                return Rect.Empty; 

            HwndSource hwndSource = presentationSource as HwndSource; 

            // If the source isn't an HwnSource, there's not much we can do, return empty rect
            if(hwndSource == null)
                return Rect.Empty; 

            Rect rectElement    = new Rect(new Point(0, 0), _owner.RenderSize); 
            Rect rectRoot       = PointUtil.ElementToRoot(rectElement, _owner, presentationSource); 
            Rect rectClient     = PointUtil.RootToClient(rectRoot, presentationSource);
            Rect rectScreen     = PointUtil.ClientToScreen(rectClient, hwndSource); 

            return rectScreen;
        }
 
        ///
        override protected bool IsOffscreenCore() 
        { 
            return !_owner.IsVisible;
        } 

        ///
        override protected AutomationOrientation GetOrientationCore()
        { 
            return (AutomationOrientation.None);
        } 
 
        ///
        override protected string GetItemTypeCore() 
        {
            return AutomationProperties.GetItemType(_owner);
        }
 
        ///
        override protected string GetClassNameCore() 
        { 
            return string.Empty;
        } 

        ///
        override protected string GetItemStatusCore()
        { 
            return AutomationProperties.GetItemStatus(_owner);
        } 
 
        ///
        override protected bool IsRequiredForFormCore() 
        {
            return AutomationProperties.GetIsRequiredForForm(_owner);
        }
 
        ///
        override protected bool IsKeyboardFocusableCore() 
        { 
            return Keyboard.IsFocusable(_owner);
        } 

        ///
        override protected bool HasKeyboardFocusCore()
        { 
            return _owner.IsKeyboardFocused;
        } 
 
        ///
        override protected bool IsEnabledCore() 
        {
            return _owner.IsEnabled;
        }
 
        ///
        override protected bool IsPasswordCore() 
        { 
            return false;
        } 

        ///
        override protected bool IsContentElementCore()
        { 
            return true;
        } 
 
        ///
        override protected bool IsControlElementCore() 
        {
            return true;
        }
 
        ///
        override protected AutomationPeer GetLabeledByCore() 
        { 
            UIElement element = AutomationProperties.GetLabeledBy(_owner);
            if (element != null) 
                return element.GetAutomationPeer();

            return null;
        } 

        /// 
        override protected string GetAcceleratorKeyCore() 
        {
            return AutomationProperties.GetAcceleratorKey(_owner); 
        }

        ///
        override protected string GetAccessKeyCore() 
        {
            string result = AutomationProperties.GetAccessKey(_owner); 
            if (string.IsNullOrEmpty(result)) 
                return AccessKeyManager.InternalGetAccessKeyCharacter(_owner);
 
            return string.Empty;
        }

        // 
        // M E T H O D S
        // 
 
        ///
        ///  
        ///     Critical    - Calls PresentationSource.CriticalFromVisual to get the source for this visual
        ///     TreatAsSafe - The returned PresenationSource object is not exposed and is only used for converting
        ///                   co-ordinates to screen space.
        ///  
        [SecurityCritical, SecurityTreatAsSafe]
        override protected Point GetClickablePointCore() 
        { 
            Point pt = new Point(double.NaN, double.NaN);
 
            PresentationSource presentationSource = PresentationSource.CriticalFromVisual(_owner);

            // If there's no source, the element is not visible, return (double.NaN, double.NaN) point
            if(presentationSource == null) 
                return pt;
 
            HwndSource hwndSource = presentationSource as HwndSource; 

            // If the source isn't an HwnSource, there's not much we can do, return (double.NaN, double.NaN) point 
            if(hwndSource == null)
                return pt;

            Rect rectElement    = new Rect(new Point(0, 0), _owner.RenderSize); 
            Rect rectRoot       = PointUtil.ElementToRoot(rectElement, _owner, presentationSource);
            Rect rectClient     = PointUtil.RootToClient(rectRoot, presentationSource); 
            Rect rectScreen     = PointUtil.ClientToScreen(rectClient, hwndSource); 

            pt = new Point(rectScreen.Left + rectScreen.Width * 0.5, rectScreen.Top + rectScreen.Height * 0.5); 

            return pt;
        }
 
        ///
        override protected void SetFocusCore() 
        { 
            if (!_owner.Focus())
                throw new InvalidOperationException(SR.Get(SRID.SetFocusFailed)); 
        }

        private UIElement _owner;
    } 
}
 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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UIElementAutomationPeer.cs source code in C# .NET

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