ModelPropertyImpl.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / Model / ModelPropertyImpl.cs / 1305376 / ModelPropertyImpl.cs
                        
                        
                            //------------------------------------------------------------------------------ 
// Copyright (c) Microsoft Corporation.  All rights reserved.
//-----------------------------------------------------------------------------

namespace System.Activities.Presentation.Model 
{
    using System.Collections.Generic; 
    using System.ComponentModel; 
    using System.Windows.Documents;
 
    // This class provides the implementation for a model property.
    // this intercepts sets /gets to the property and works with modeltreemanager
    // to keep the xaml in [....].
 
    class ModelPropertyImpl : ModelProperty
    { 
        object defaultValue; 
        ModelItem parent;
        PropertyDescriptor propertyDescriptor; 
        AttributeCollection attributes;
        bool isAttached = false;

        public ModelPropertyImpl(ModelItem parent, PropertyDescriptor propertyDescriptor, bool isAttached) 
        {
            this.parent = parent; 
            this.propertyDescriptor = propertyDescriptor; 

            // using this a marker to indicate this hasnt been computed yet. 
            this.defaultValue = this;
            this.isAttached = isAttached;
        }
 
        public override Type AttachedOwnerType
        { 
            get 
            {
                return this.parent.GetType(); 
            }
        }

        public override AttributeCollection Attributes 
        {
            get 
            { 
                if (this.attributes == null)
                { 
                    if (propertyDescriptor.ComponentType.IsGenericType)
                    {
                        List attributeList = new List(this.propertyDescriptor.Attributes.Count);
                        foreach (Attribute attr in this.propertyDescriptor.Attributes) 
                        {
                            attributeList.Add(attr); 
                        } 

                        // Merge propertyDescriptor.Attributes with generic type definition Attributes 
                        Type genericInstanceType = propertyDescriptor.ComponentType.GetGenericTypeDefinition();
                        PropertyDescriptor pd = TypeDescriptor.GetProvider(genericInstanceType).GetTypeDescriptor(genericInstanceType).GetProperties()[this.Name];
                        if (null != pd)
                        { 
                            foreach (Attribute attr in pd.Attributes)
                            { 
                                if (!attributeList.Contains(attr)) 
                                {
                                    attributeList.Add(attr); 
                                }
                            }
                        }
                        this.attributes = new AttributeCollection(attributeList.ToArray()); 
                    }
                    else 
                    { 
                        this.attributes = propertyDescriptor.Attributes;
                    } 
                }
                return this.attributes;
            }
        } 

        public override ModelItemCollection Collection 
        { 
            get
            { 
                return this.Value as ModelItemCollection;
            }
        }
 
        public override object ComputedValue
        { 
            get 
            {
                object computedValue = null; 
                if (this.Value != null)
                {
                    computedValue = Value.GetCurrentValue();
                } 
                return computedValue;
            } 
            set 
            {
                SetValue(value); 
            }
        }

        public override System.ComponentModel.TypeConverter Converter 
        {
            get 
            { 
                return new ModelTypeConverter(((IModelTreeItem)this.Parent).ModelTreeManager, propertyDescriptor.Converter);
            } 
        }

        public override object DefaultValue
        { 
            get
            { 
                if (Object.ReferenceEquals(this.defaultValue, this)) 
                {
                    DefaultValueAttribute defaultValueAttribute = this.propertyDescriptor.Attributes[typeof(DefaultValueAttribute)] as DefaultValueAttribute; 
                    this.defaultValue = (defaultValueAttribute == null) ? null : defaultValueAttribute.Value;
                }
                return this.defaultValue;
            } 
        }
 
        public override ModelItemDictionary Dictionary 
        {
            get 
            {
                return Value as ModelItemDictionary;
            }
        } 

        public override bool IsAttached 
        { 
            get
            { 
                return this.isAttached;
            }
        }
 
        public override bool IsBrowsable
        { 
            get 
            {
                return propertyDescriptor.IsBrowsable; 
            }
        }

        public override bool IsCollection 
        {
            get { return this.Value is ModelItemCollection; } 
        } 

        public override bool IsDictionary 
        {
            get { return this.Value is ModelItemDictionary; }
        }
 
        public override bool IsReadOnly
        { 
            get 
            {
                return propertyDescriptor.IsReadOnly; 
            }
        }

        public override bool IsSet 
        {
            get 
            { 
                return this.Value != null;
            } 
        }

        public override string Name
        { 
            get
            { 
                return propertyDescriptor.Name; 
            }
        } 

        public override ModelItem Parent
        {
            get 
            {
                return parent; 
            } 
        }
 
        public override Type PropertyType
        {
            get
            { 
                return propertyDescriptor.PropertyType;
            } 
        } 

        public override ModelItem Value 
        {
            get
            {
                return ((IModelTreeItem)parent).ModelTreeManager.GetValue(this); 
            }
        } 
 
        internal PropertyDescriptor PropertyDescriptor
        { 
            get
            {
                return propertyDescriptor;
            } 
        }
 
        public override void ClearValue() 
        {
            if (!this.IsReadOnly) 
            {
                ((IModelTreeItem)parent).ModelTreeManager.ClearValue(this);
            }
        } 

        public override ModelItem SetValue(object value) 
        { 
            return ((IModelTreeItem)parent).ModelTreeManager.SetValue(this, value);
        } 

        internal object SetValueCore(ModelItem newValueModelItem)
        {
            object newValueInstance = (newValueModelItem == null) ? null : newValueModelItem.GetCurrentValue(); 
            ModelItem oldValueModelItem = this.Value;
            IModelTreeItem parent = (IModelTreeItem)this.Parent; 
 
            // try update the instance
            this.PropertyDescriptor.SetValue(this.Parent.GetCurrentValue(), newValueInstance); 

            // if old value is not null remove parent/source from it and release it
            if (oldValueModelItem != null)
            { 
                ((IModelTreeItem)oldValueModelItem).RemoveSource(this);
                parent.ModelTreeManager.ReleaseModelItem(oldValueModelItem, this.Parent); 
            } 

            // if new value is non null, update parent/source for it. 
            if (newValueModelItem != null)
            {
                parent.ModelTreeManager.ReAddModelItemToModelTree(newValueModelItem);
                parent.ModelPropertyStore[this.Name] = newValueModelItem; 
                ((IModelTreeItem)newValueModelItem).SetSource(this);
            } 
            else 
            {
                parent.ModelPropertyStore.Remove(this.Name); 
            }

            // notify observers
            ((IModelTreeItem)this.Parent).OnPropertyChanged(this.Name); 
            return newValueInstance;
        } 
    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
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ModelPropertyImpl.cs source code in C# .NET

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