StrokeCollectionDefaultValueFactory.cs source code in C# .NET

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Code:

/ Net / Net / 3.5.50727.3053 / DEVDIV / depot / DevDiv / releases / Orcas / SP / wpf / src / Framework / MS / Internal / Ink / StrokeCollectionDefaultValueFactory.cs / 1 / StrokeCollectionDefaultValueFactory.cs

                            //---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: DefaultValueFactory for StrokeCollection 
// 
// History:
//  2006/01/24 : waynezen - Created 
//
//---------------------------------------------------------------------------

using System; 
using System.Diagnostics;
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Ink;
 
namespace MS.Internal.Ink
{
    internal class StrokeCollectionDefaultValueFactory : DefaultValueFactory
    { 
        internal StrokeCollectionDefaultValueFactory()
        { 
        } 

        ///  
        ///     Returns an "immutable" default value. Since we can't make the default value
        ///     read only we'll return a new one every time.
        /// 
        internal override object DefaultValue 
        {
            get 
            { 
                return new StrokeCollection();
            } 
        }

        /// 
        ///     Creates a mutable default value 
        /// 
        internal override object CreateDefaultValue(DependencyObject owner, DependencyProperty property) 
        { 
            Debug.Assert(property.PropertyType == typeof(StrokeCollection),
                string.Format(System.Globalization.CultureInfo.InvariantCulture, "The DependencyProperty {0} has to be type of StrokeCollection.", property)); 

            // Instantiate our default value instance.
            StrokeCollection defaultValue = new StrokeCollection();
 
            // Add event handlers for tracking the changes on the default value instance.
            StrokeCollectionDefaultPromoter promoter = new StrokeCollectionDefaultPromoter(owner, property); 
 
            defaultValue.StrokesChanged +=
                new StrokeCollectionChangedEventHandler(promoter.OnStrokeCollectionChanged); 
            defaultValue.PropertyDataChanged +=
                new PropertyDataChangedEventHandler(promoter.OnStrokeCollectionChanged);

            return defaultValue; 
        }
 
        ///  
        /// A tracking class which monitors any changes on StrokeCollection
        ///  
        private class StrokeCollectionDefaultPromoter
        {
            /// 
            /// Constructor 
            /// 
            ///  
            ///  
            internal StrokeCollectionDefaultPromoter(DependencyObject owner, DependencyProperty property)
            { 
                _owner = owner;
                _dependencyProperty = property;
            }
 
            /// 
            /// A handler for both AttributeChanged and PropertyDataChanged. 
            ///  
            /// 
            ///  
            internal void OnStrokeCollectionChanged(object sender, TEventArgs e)
            {
                StrokeCollection value = (StrokeCollection)sender;
 
                // The current instance will be promoted to the local value other than the default value.
                // Then we could just remove our handlers to stop tracking. 
                value.StrokesChanged -= 
                    new StrokeCollectionChangedEventHandler(OnStrokeCollectionChanged);
                value.PropertyDataChanged -= 
                    new PropertyDataChangedEventHandler(OnStrokeCollectionChanged);

                // NTRAID#WINDOWS-1334059-2005/10/17-waynezen,
                // We only promote the value when there is no local value set yet. 
                if ( _owner.ReadLocalValue(_dependencyProperty) == DependencyProperty.UnsetValue )
                { 
                    // Promote the instance to the local value. 
                    _owner.SetValue(_dependencyProperty, value);
                } 

                // Remove this value from the DefaultValue cache so we stop
                // handing it out as the default value now that it has changed.
                PropertyMetadata metadata = _dependencyProperty.GetMetadata(_owner.DependencyObjectType); 
                metadata.ClearCachedDefaultValue(_owner, _dependencyProperty);
            } 
 
            private readonly DependencyObject   _owner;
            private readonly DependencyProperty _dependencyProperty; 
        }
    }
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
//---------------------------------------------------------------------------- 
//
// 
//    Copyright (C) Microsoft Corporation.  All rights reserved.
//  
//
// Description: DefaultValueFactory for StrokeCollection 
// 
// History:
//  2006/01/24 : waynezen - Created 
//
//---------------------------------------------------------------------------

using System; 
using System.Diagnostics;
using System.Windows; 
using System.Windows.Controls; 
using System.Windows.Ink;
 
namespace MS.Internal.Ink
{
    internal class StrokeCollectionDefaultValueFactory : DefaultValueFactory
    { 
        internal StrokeCollectionDefaultValueFactory()
        { 
        } 

        ///  
        ///     Returns an "immutable" default value. Since we can't make the default value
        ///     read only we'll return a new one every time.
        /// 
        internal override object DefaultValue 
        {
            get 
            { 
                return new StrokeCollection();
            } 
        }

        /// 
        ///     Creates a mutable default value 
        /// 
        internal override object CreateDefaultValue(DependencyObject owner, DependencyProperty property) 
        { 
            Debug.Assert(property.PropertyType == typeof(StrokeCollection),
                string.Format(System.Globalization.CultureInfo.InvariantCulture, "The DependencyProperty {0} has to be type of StrokeCollection.", property)); 

            // Instantiate our default value instance.
            StrokeCollection defaultValue = new StrokeCollection();
 
            // Add event handlers for tracking the changes on the default value instance.
            StrokeCollectionDefaultPromoter promoter = new StrokeCollectionDefaultPromoter(owner, property); 
 
            defaultValue.StrokesChanged +=
                new StrokeCollectionChangedEventHandler(promoter.OnStrokeCollectionChanged); 
            defaultValue.PropertyDataChanged +=
                new PropertyDataChangedEventHandler(promoter.OnStrokeCollectionChanged);

            return defaultValue; 
        }
 
        ///  
        /// A tracking class which monitors any changes on StrokeCollection
        ///  
        private class StrokeCollectionDefaultPromoter
        {
            /// 
            /// Constructor 
            /// 
            ///  
            ///  
            internal StrokeCollectionDefaultPromoter(DependencyObject owner, DependencyProperty property)
            { 
                _owner = owner;
                _dependencyProperty = property;
            }
 
            /// 
            /// A handler for both AttributeChanged and PropertyDataChanged. 
            ///  
            /// 
            ///  
            internal void OnStrokeCollectionChanged(object sender, TEventArgs e)
            {
                StrokeCollection value = (StrokeCollection)sender;
 
                // The current instance will be promoted to the local value other than the default value.
                // Then we could just remove our handlers to stop tracking. 
                value.StrokesChanged -= 
                    new StrokeCollectionChangedEventHandler(OnStrokeCollectionChanged);
                value.PropertyDataChanged -= 
                    new PropertyDataChangedEventHandler(OnStrokeCollectionChanged);

                // NTRAID#WINDOWS-1334059-2005/10/17-waynezen,
                // We only promote the value when there is no local value set yet. 
                if ( _owner.ReadLocalValue(_dependencyProperty) == DependencyProperty.UnsetValue )
                { 
                    // Promote the instance to the local value. 
                    _owner.SetValue(_dependencyProperty, value);
                } 

                // Remove this value from the DefaultValue cache so we stop
                // handing it out as the default value now that it has changed.
                PropertyMetadata metadata = _dependencyProperty.GetMetadata(_owner.DependencyObjectType); 
                metadata.ClearCachedDefaultValue(_owner, _dependencyProperty);
            } 
 
            private readonly DependencyObject   _owner;
            private readonly DependencyProperty _dependencyProperty; 
        }
    }
}

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

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