ModelProperty.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / ndp / cdf / src / NetFx40 / Tools / System.Activities.Presentation / System / Activities / Presentation / Base / Interaction / Model / ModelProperty.cs / 1305376 / ModelProperty.cs
                        

                        
                            //------------------------------------------------------------------------------ 
// 
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// 
//----------------------------------------------------------------------------- 

namespace System.Activities.Presentation.Model { 
 
    using System.Activities.Presentation.Internal.Properties;
    using System; 
    using System.ComponentModel;
    using System.Diagnostics.CodeAnalysis;
    using System.Globalization;
    using System.Runtime; 

    ///  
    /// An ModelProperty represents a property on an item.  ModelProperties are 
    /// associated with an instance of an item, which allows them to have simple
    /// Value get/set properties instead of the more cumbersome GetValue/SetValue 
    /// mechanism of PropertyDescriptor.
    ///
    /// A ModelProperty�s value may come from a locally set value, or it may be
    /// inherited from somewhere higher up in the property mechanism.  Because 
    /// all items in the tree contain Source properties, you can
    /// easily find out the real source of a property value simply using the 
    /// following code: 
    ///
    ///     Console.WriteLine(property.Value.Source); 
    ///
    /// Value will return null if the property is not set anywhere in the hierarchy.
    ///
    /// Type converters and editors defined on the underlying data model are 
    /// wrapped so that they accept ModelItems as parameters.
    ///  
    public abstract class ModelProperty { 

        ///  
        /// Creates a new ModelProperty.
        /// 
        protected ModelProperty() { }
 
        /// 
        /// Returns the attributes declared on this property. 
        ///  
        public abstract AttributeCollection Attributes { get; }
 
        /// 
        /// Returns Value cast as a ModelItemCollection.  This property allows you to
        /// access collection properties easily without cluttering your code with casts:
        /// 
        ///     Property.Collection.Add(myItem);
        /// 
        /// If the property value is not a collection, this property will return null. 
        /// 
        [Fx.Tag.KnownXamlExternalAttribute] 
        public abstract ModelItemCollection Collection { get; }

        /// 
        /// Returns the currently computed value for this property.  Setting a value 
        /// on this property is the same as calling SetValue, but can be used in
        /// data binding expressions. 
        ///  
        public abstract object ComputedValue { get; set; }
 
        /// 
        /// Returns the type converter to use with this property.  Underlying type
        /// converters are all wrapped so they accept Item objects.  When performing
        /// a conversion to a particular value, the type converter�s return type is 
        /// not wrapped.  Type converters which return standard values also return
        /// values as Item objects. 
        ///  
        public abstract TypeConverter Converter { get; }
 
        /// 
        /// Returns the type which defines this property if IsAttached returns true.
        /// Otherwhise, returns null.
        ///  
        public abstract Type AttachedOwnerType { get; }
 
        ///  
        /// Returns the default value for this property.  If the property does not
        /// define a default value this will return null. 
        /// 
        public abstract object DefaultValue { get; }

        ///  
        /// Returns Value cast as a ItemDictionary.  This property allows you to
        /// access dictionary properties easily without cluttering your code with casts: 
        /// 
        ///     Property.Dictionary[key] = value;
        /// 
        /// If the property value is not a dictionary, this property will return null.
        /// 
        [Fx.Tag.KnownXamlExternalAttribute]
        public abstract ModelItemDictionary Dictionary { get; } 

        ///  
        /// Returns true if the property can be shown in a property window. 
        /// 
        public abstract bool IsBrowsable { get; } 

        /// 
        /// Returns true if the value contained in the property is a ItemCollection.
        ///  
        public abstract bool IsCollection { get; }
 
        ///  
        /// Returns true if the value contained in the property is a ItemDictionary.
        ///  
        public abstract bool IsDictionary { get; }

        /// 
        /// Returns true if the property is read only. 
        /// 
        public abstract bool IsReadOnly { get; } 
 
        /// 
        /// Returns true if the property�s value is set locally. 
        /// 
        public abstract bool IsSet { get; }

        ///  
        /// Returns true if the property represents an attached property from a different type.
        ///  
        public abstract bool IsAttached { get; } 

        ///  
        /// Returns the value set into this property.  A property may return a
        /// value that is inherited further up the element hierarchy, in which
        /// case this property will return a value whose source != this.
        /// If no value has ever been set for the property Value will return null. 
        /// 
        public abstract ModelItem Value { get; } 
 
        /// 
        /// Returns the name of this property. 
        /// 
        public abstract string Name { get; }

        ///  
        /// Returns the parent of this property.  All properties have
        /// parents, so this never returns null. 
        ///  
        public abstract ModelItem Parent { get; }
 
        /// 
        /// The data type of the property.
        /// 
        public abstract Type PropertyType { get; } 

        ///  
        /// Clears the local value for the property. 
        /// 
        public abstract void ClearValue(); 

        /// 
        /// Sets a local value on a property.  If this value is already
        /// a ModelItem, it will be used directly.  If it isn�t, a ModelItem 
        /// will be created.  Setting null into a property is valid, but
        /// this is not the same as calling ClearValue(). 
        ///  
        /// 
        /// The new value to set. 
        /// 
        /// 
        /// The input value, if the value is already a ModelItem, or a newly
        /// created ModelItem wrapping the value. 
        /// 
        public abstract ModelItem SetValue(object value); 
 
        /// 
        /// Equality operator. 
        /// 
        // FXCop: args are validated; fxcop does not seem to understand ReferenceEquals.

        public static bool operator ==(ModelProperty first, ModelProperty second) { 
            if (object.ReferenceEquals(first, second)) return true;
            if (object.ReferenceEquals(first, null) || object.ReferenceEquals(second, null)) return false; 
            return (first.Parent == second.Parent && first.Name.Equals(second.Name)); 
        }
 
        /// 
        /// Inequality operator.
        /// 
        // FXCop: args are validated; fxcop does not seem to understand ReferenceEquals. 

        public static bool operator !=(ModelProperty first, ModelProperty second) { 
            if (object.ReferenceEquals(first, second)) return false; 
            if (object.ReferenceEquals(first, null) || object.ReferenceEquals(second, null)) return true;
            return (first.Parent != second.Parent || !first.Name.Equals(second.Name)); 
        }

        /// 
        /// Equality for properties.  Properties are equal if 
        /// they have the same name and parent.
        ///  
        ///  
        /// 
        public override bool Equals(object obj) { 
            if (object.ReferenceEquals(obj, this)) return true;
            ModelProperty prop = obj as ModelProperty;
            if (object.ReferenceEquals(prop, null)) return false;
            if (prop.Parent != Parent) return false; 
            return prop.Name.Equals(Name);
        } 
 
        /// 
        /// Standard hashcode implementation. 
        /// 
        /// 
        public override int GetHashCode() {
            return Parent.GetHashCode() ^ Name.GetHashCode(); 
        }
    } 
} 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.

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