DependencyPropertyKind.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Base / MS / Internal / ComponentModel / DependencyPropertyKind.cs / 1 / DependencyPropertyKind.cs
                        

                        
                            namespace MS.Internal.ComponentModel
{
    using System;
    using System.Windows; 

    // 
    // Determines what kind of DP we are dealing with.  DependencyPropertyKind 
    // is associated with a target type and a DP.  It calculates IsAttached
    // and IsDirect on demand using the following rules: 
    //
    // IsAttached is true iff:
    //
    //      1.  The target type is not a registered owner of the DP, or 
    //          the target type is the DP's owner type.
    // 
    //      2.  The DP's owner type offers a public static Get method 
    //          with the same name as the DP.  The method must
    //          have the correct signature (one parameter that derives 
    //          from DependencyObject).
    //
    // IsDirect is true iff:
    // 
    //      1.  The target type is a registered owner of the DP.
    // 
    //      2.  The target type offers a public CLR property of the 
    //          same name as the DP.
    // 
    // If neither of these is true the property is assumed to be internal
    // and therefore inaccessible to anyone via reflection.
    //
    // A property cannot be both attached and direct.  If a property defines 
    // both accessors direct accessors take precidence.
    // 
    internal class DependencyPropertyKind 
    {
        //------------------------------------------------------ 
        //
        //  Internal Constructors
        //
        //----------------------------------------------------- 

        // 
        // Creates a new instance 
        //
        internal DependencyPropertyKind(DependencyProperty dp, Type targetType) 
        {
            _dp = dp;
            _targetType = targetType;
        } 

        //----------------------------------------------------- 
        // 
        //  Internal Properties
        // 
        //-----------------------------------------------------

        //
        // Returns true if the property is internal. 
        //
        internal bool IsInternal 
        { 
            get
            { 
                if (!_isInternalChecked)
                {
                    // The property is internal if it has no public
                    // static Get method or no public CLR accessor.  If we already 
                    // calculated it to be a direct or attached property, bail because
                    // it's clearly not internal. 
 
                    if (!_isAttached && !_isDirect)
                    { 
                        if (DependencyObjectPropertyDescriptor.GetAttachedPropertyMethod(_dp) == null &&
                            _dp.OwnerType.GetProperty(_dp.Name) == null)
                        {
                            _isInternal = true; 
                        }
                    } 
 
                    _isInternalChecked = true;
                } 

                return _isInternal;
            }
        } 

        // 
        // Returns true if the property is attached for the target type. 
        //
        internal bool IsAttached 
        {
            get
            {
                if (!_isAttachedChecked) 
                {
                    // A property cannot be both attached and direct, 
                    // so if this property is already direct we have our 
                    // answer.  Note that we check the IsDirect property
                    // here to force evaluation.  Direct takes precidence 
                    // over attached on the same object, so we need to
                    // force the check if it hasn't been done.

                    if (!IsDirect) 
                    {
                        // If the attached property is AddOwnered to this type, we 
                        // don't treat it as attached because, by definition, attached 
                        // properties can only have one owner, and any AddOwnered version
                        // beceomes a direct property. 

                        if (_dp.OwnerType == _targetType || _dp.OwnerType.IsAssignableFrom(_targetType) || DependencyProperty.FromName(_dp.Name, _targetType) != _dp)
                        {
                            if (DependencyObjectPropertyDescriptor.GetAttachedPropertyMethod(_dp) != null) 
                            {
                                _isAttached = true; 
                            } 
                        }
                    } 

                    _isAttachedChecked = true;
                }
 
                return _isAttached;
            } 
        } 

        // 
        // Returns true if the property is direct for the target type.
        //
        internal bool IsDirect
        { 
            get
            { 
                if (!_isDirectChecked) 
                {
                    // If we've already calculated attached, we 
                    // know the answer if _isAttached is true because
                    // a property cannot be both.

                    // No need to also check _isAttachedChecked since this will 
                    // only be true if the check has been done.
                    if (!_isAttached) 
                    { 
                        if (DependencyProperty.FromName(_dp.Name, _targetType) == _dp)
                        { 
                            if (_targetType.GetProperty(_dp.Name) != null)
                            {
                                _isDirect = true;
                                _isAttachedChecked = true; 
                            }
                        } 
                    } 

                    _isDirectChecked = true; 
                }

                return _isDirect;
            } 
        }
 
 
        //------------------------------------------------------
        // 
        //  Private Fields
        //
        //-----------------------------------------------------
 

        private readonly DependencyProperty _dp; 
        private readonly Type _targetType; 
        private bool _isAttached;
        private bool _isAttachedChecked; 
        private bool _isInternal;
        private bool _isInternalChecked;
        private bool _isDirect;
        private bool _isDirectChecked; 
    }
} 
 

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

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