namespace MS.Internal.ComponentModel
{
    using System;
    using System.Windows;
 
    /// <summary>
    ///     This attribute is synthesized by our DependencyObjectProvider
    ///     to relate a property descriptor back to a dependency property.
    /// </summary>
    [AttributeUsage(AttributeTargets.Method)]
    internal sealed class DependencyPropertyAttribute : Attribute 
    {
 
        //------------------------------------------------------
        //
        //  Constructors
        //
        //------------------------------------------------------
 
        #region Constructors
        
        /// <summary>
        ///     Creates a new DependencyPropertyAttribute for the given dependency property.
        /// </summary>
        internal DependencyPropertyAttribute(DependencyProperty dependencyProperty, bool isAttached) 
        {
            if (dependencyProperty == null) throw new ArgumentNullException("dependencyProperty");
 
            _dp = dependencyProperty;
            _isAttached = isAttached;
        }
 
        #endregion Constructors
 
        //------------------------------------------------------
        //
        //  Public Methods
        //
        //------------------------------------------------------
 
        #region Public Methods
        
        /// <summary>
        ///     Override of Object.Equals that returns true when the dependency
        ///     property contained within each attribute is the same.
        /// </summary>
        public override bool Equals(object value) 
        {
            DependencyPropertyAttribute da = value as DependencyPropertyAttribute;
 
            if (da != null && 
                object.ReferenceEquals(da._dp, _dp) && 
                da._isAttached == _isAttached) 
            {
                return true;
            }
 
            return false;
        }
 
        /// <summary>
        ///     Override of Object.GetHashCode();
        /// </summary>
        public override int GetHashCode() 
        {
            return _dp.GetHashCode();
        }
 
        #endregion Public Methods
        
        //------------------------------------------------------
        //
        //  Public Operators
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Public Properties
        //
        //------------------------------------------------------
 
        #region Public Properties
 
        /// <summary>
        ///     Overrides Attribute.TypeId to be unique with respect to
        ///     other dependency property attributes.c
        /// </summary>
        public override object TypeId 
        {
            get { return typeof(DependencyPropertyAttribute); }
        }
 
        #endregion Public Properties
 
 
        //------------------------------------------------------
        //
        //  Public Events
        //
        //------------------------------------------------------
 
        //------------------------------------------------------
        //
        //  Internal Properties
        //
        //------------------------------------------------------
 
        #region Internal Properties
        
        /// <summary>
        ///     Returns whether the dependency property is an attached
        ///     property.
        /// </summary>
        internal bool IsAttached
        {
            get { return _isAttached; }
        }
        
        /// <summary>
        ///     Returns the dependency property instance this attribute is
        ///     associated with.
        /// </summary>
        internal DependencyProperty DependencyProperty 
        {
            get { return _dp; }
        }
 
        #endregion Internal Properties
 
        //------------------------------------------------------
        //
        //  Private Fields
        //
        //------------------------------------------------------
 
        #region Private Fields
        
        private DependencyProperty _dp;
        private bool _isAttached;
 
        #endregion Private Fields
    }
}