Code:
/ 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Base / MS / Internal / ComponentModel / DependencyObjectProvider.cs / 1305600 / DependencyObjectProvider.cs
namespace MS.Internal.ComponentModel { using MS.Internal.ComponentModel; using System; using System.Collections; using System.Collections.Generic; using System.ComponentModel; using System.Diagnostics; using System.Reflection; using System.Windows; using System.Windows.Markup; using System.Text; ////// A type description provider provides metadata for types. It allows a type /// to define its own semantic layer for properties, events and attributes. /// /// Note: This class can stay internal. To utilize it, the following /// metadata attribute should be added to DependencyObject: /// /// [TypeDescriptionProvider(typeof(DependencyObjectProvider))] /// public class DependencyObject {} /// internal sealed class DependencyObjectProvider : TypeDescriptionProvider { //------------------------------------------------------ // // Constructors // //----------------------------------------------------- #region Constructors ////// The ctor for this class needs to be public because it is created /// by TypeDescriptor using reflection. /// public DependencyObjectProvider() : base(TypeDescriptor.GetProvider(typeof(DependencyObject))) { // We keep a lot of caches around. When TypeDescriptor gets a refresh // we clear our caches. We only need to do this if the refresh // contains type information, because we only keep static per-type // caches. TypeDescriptor.Refreshed += delegate(RefreshEventArgs args) { if (args.TypeChanged != null && typeof(DependencyObject).IsAssignableFrom(args.TypeChanged)) { ClearCache(); DependencyObjectPropertyDescriptor.ClearCache(); DPCustomTypeDescriptor.ClearCache(); DependencyPropertyDescriptor.ClearCache(); } }; } #endregion Constructors //----------------------------------------------------- // // Public Methods // //----------------------------------------------------- #region Public Methods ////// Returns a custom type descriptor suitable for querying about the /// given object type and instance. /// public override ICustomTypeDescriptor GetTypeDescriptor(Type objectType, object instance) { return new DPCustomTypeDescriptor(base.GetTypeDescriptor(objectType, instance), objectType, instance); } ////// Returns a custom type descriptor suitable for querying about "extended" /// properties. Extended properties are are attached properties in our world. /// public override ICustomTypeDescriptor GetExtendedTypeDescriptor(object instance) { ICustomTypeDescriptor descriptor = base.GetExtendedTypeDescriptor(instance); // It is possible that a Type object worked its way in here as an instance. // If it did, we don't need our own descriptor because we don't support // attached properties on type instances. if (instance != null && !(instance is Type)) { descriptor = new APCustomTypeDescriptor(descriptor, instance); } return descriptor; } ////// Returns a caching layer type descriptor will use to store /// computed metadata. /// public override IDictionary GetCache(object instance) { DependencyObject d = instance as DependencyObject; // This should never happen because we are bound only // to dependency object types. However, in case it // does, simply invoke the base and get out. if (d == null) { return base.GetCache(instance); } // The cache we return is used by TypeDescriptor to // store cached metadata information. We demand create // it here. // If the DependencyObject is Sealed we cannot store // the cache on it - if no cache exists already we // will return null. IDictionary cache = _cacheSlot.GetValue(d); if (cache == null && !d.IsSealed) { cache = new Hashtable(); _cacheSlot.SetValue(d, cache); } return cache; } #endregion Public Methods //------------------------------------------------------ // // Public Properties // //----------------------------------------------------- //------------------------------------------------------ // // Public Events // //------------------------------------------------------ //----------------------------------------------------- // // Private Methods // //------------------------------------------------------ #region Private Methods ////// This method is called when we should clear our cached state. The cache /// may become invalid if someone adds additional type description providers. /// private static void ClearCache() { lock (_propertyMap) { _propertyMap.Clear(); } lock(_propertyKindMap) { _propertyKindMap.Clear(); } lock(_attachInfoMap) { _attachInfoMap.Clear(); } } ////// This method calculates the attach rules defined on /// this dependency property. It always returns a valid /// AttachInfo, but the fields in AttachInfo may be null. /// internal static AttachInfo GetAttachInfo(DependencyProperty dp) { // Have we already seen this DP? AttachInfo info = (AttachInfo)_attachInfoMap[dp]; if (info == null) { info = new AttachInfo(dp); lock(_attachInfoMap) { _attachInfoMap[dp] = info; } } return info; } #endregion Private Methods //----------------------------------------------------- // // Internal Methods // //----------------------------------------------------- #region Internal Methods ////// This method returns an attached property descriptor for the given DP and target type. /// internal static DependencyObjectPropertyDescriptor GetAttachedPropertyDescriptor(DependencyProperty dp, Type targetType) { DependencyObjectPropertyDescriptor dpProp; PropertyKey key = new PropertyKey(targetType, dp); lock(_propertyMap) { if (!_propertyMap.TryGetValue(key, out dpProp)) { dpProp = new DependencyObjectPropertyDescriptor(dp, targetType); _propertyMap[key] = dpProp; } } return dpProp; } ////// This method returns a DependencyPropertyKind object which can /// be used to tell if a given DP / target type combination represents /// an attached or direct property. /// internal static DependencyPropertyKind GetDependencyPropertyKind(DependencyProperty dp, Type targetType) { DependencyPropertyKind kind; PropertyKey key = new PropertyKey(targetType, dp); lock(_propertyKindMap) { if (!_propertyKindMap.TryGetValue(key, out kind)) { kind = new DependencyPropertyKind(dp, targetType); _propertyKindMap[key] = kind; } } return kind; } #endregion Internal Methods //----------------------------------------------------- // // Private Fields // //------------------------------------------------------ #region Private Fields private static readonly UncommonField_cacheSlot = new UncommonField (null); // Synchronized by "_propertyMap" private static Dictionary _propertyMap = new Dictionary (); // Synchronized by "_propertyKindMap" private static Dictionary _propertyKindMap = new Dictionary (); // Synchronized by "_attachInfoMap" private static Hashtable _attachInfoMap = new Hashtable(); #endregion Private Fields } } // File provided for Reference Use Only by Microsoft Corporation (c) 2007. // Copyright (c) Microsoft Corporation. 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